3. nbsp;nbsp;nbsp;Lower Cretaceous flora of the Black Hills, other than cyeadean

ILLUSTRATIONS.

CLXIX. Taxaceous and dicotyledonous plants, and plants of uncertain systematic position, from the Lower Cretaceous

122. nbsp;nbsp;nbsp;General section of the strata occurring in the Hay Creek coal field.

THE CRETACEOUS FORMATION OF THE BLACK HIT.I.S AS INDICATED BY THE FOSSIL PLANTS.

The Black Hills are au object lesson in geology. An isolated spur or outlier of the Rocky Mountains, but separated from the main rangenbsp;by valleys and plains of considerable vidth, they seem to stand alonenbsp;as a landmark of the Great Plains, presenting from a distance a darknbsp;and frowning aspect, which has given them their name. Their ellipticalnbsp;form, the granitic nucleus of the central portion, and the series of successively higher formations that concentrically surround this nucleus,nbsp;imbricated over one another and stretching away in all directions withnbsp;diminishing dip, have been too often described to require redescriptionnbsp;here.

The history of the discovery of the Black Hills has also often been written and need not be rejieated, and we are therefore in condition tonbsp;proceed directly to the consideration of the specific problems in hand,nbsp;and may confine our attention almost exclusively to the one formationnbsp;named in the title of this paper, viz, the Cretaceous. Indeed, the limitations of our subject enable us to leave out of account that part ofnbsp;the Cretaceous formation itself which has received the largest amountnbsp;of attention from other writers, viz, the marine shell-bearing depositsnbsp;which occupy its upper portion. These, not having thus far yielded anynbsp;fossil plants, will be treated in this paper only in relation to the lowernbsp;beds, and we are restricted to those deposits which lie between the Portnbsp;Benton shales above and the marine shell-bearing Jurassic formationnbsp;below.

The great exploring expeditions of Lewis and Clark, 1804-1806; of Maximilian, Prince of Reuwied, 1832; of Nicollet, 1839; and of Audubon, 1843, which so enriched our knowledge of the Great Northwest,nbsp;all followed the valley of the Missouri River so closely as not to penetrate the Black Hills, and only vague mentions are to be found in the

reports of these expeditions of a dark object looming- up in the distance. But it was otherwise with the important expedition with which thenbsp;name of John Jacob Astor is so intimately connected and which hasnbsp;been made famous by the eloquent pen of Washington Irving.^ Thisnbsp;expedition was made in 1811, under the immediate direction of Mr.nbsp;Wilson P. Hunt. Its object was entirely mercantile and not at allnbsp;scientific, yet many of the facts that were recorded iu Mr. Hunt�snbsp;notebook aTid by other members of the party and worked into the narrative twenty-five years afterwards, have a true scientific value�evennbsp;to some extent a geological value. It is at least true that the exploringnbsp;party left the Missouri River at the mouth of the Cheyenne, followednbsp;that river up some distance, crossed over to the valley of the Littlenbsp;Missouri, and from there skirted the northern limits of the Black Hillsnbsp;proper, and passed on to the Big Horn region. The greater part of thenbsp;narative is taken up with descriptions of the jnountains, the nativenbsp;Indians, and the wild animals that were met with. But soon afternbsp;leaving the Missouri Eiver the party encountered a fossil forest, whichnbsp;is described in the following terms:

These plains, however, had not always been equally destitute of wood, as was evident from the trirnks of trees which the travellers repeatedly met with, some still standing, others lying about iu broken fragments, but all in a fossil state, havingnbsp;flourished in times long past. In these singular remains the original grain of thenbsp;wood was still so distinct that they could be ascertained to be the ruins of oak trees.nbsp;Several pieces of the fossil wood were selected by the men to serve as whetstones.^

There is no probability that these fossil trunks belonged to the Cretaceous formation, certainly not to the Lower Cretaceous, and they were probably the same as those now known to exist iu the valley of thenbsp;Little Missouri, especially in the vicinity of Gladstone, which are usuallynbsp;referred to the Fort Union groiip.

The apiiroach of the party to the Black Hills is graphically described? but there is so much that is fanciful in the description that the scientificnbsp;man must depend upon his own judgment as to what the facts werenbsp;upon which these high sounding accounts were based. To those whonbsp;arc acquainted with that country now it is not difficult to do this, andnbsp;therefore the following description, perhaps the first that was ever madenbsp;of the Black Hills, still possesses a scientific interest independent ofnbsp;the classic language iu which it is couched:

The Black Hills are chiefly composed of sandstone, and in many places are broken into savage clifls and precipices, and present the most singular and fantastic forms;nbsp;sometimes resembling towns and castellated fortresses. The ignorant inhabitants ofnbsp;plains are prone to clothe the mountains that bound their horizon with fanciful andnbsp;superstitious attributes. Thus the wandering tribes of the prairies, who often beholdnbsp;clouds gathering round the summits of these hills, and lightning flashing, and th)in-dor pealing from them, when all the neighboring plains are serene and snnny, consider them the abode of the genii or thunder spirits, who fabricate storms and

� Astoria, or Anecodotes of an Enterprise beyond the Itocky Mountains, by Washington Irving, in two volumes, Pbiladelpliia, 1836.

tempests. On entering their defiles, therefore, they often hang offerings on the trees or place them on the rocks, to propitiate the invisible �lords of the mountains,� andnbsp;procure good weather and successful hunting; and they attach nunsnal significancenbsp;to the echoes which haunt the precipices. This superstition may also have arisen,nbsp;in part, from a natural phenomenon of a singular nature. In the most calm andnbsp;serene weather, and at all times of the day or night, successive reports are now andnbsp;then heard among those mountains resembling the discharge of several pieces ofnbsp;artillery. Similar reports -were heard by Messrs. Lewis and Clarke in the Rockynbsp;Mountains, which they say were attributed by the Indians to the bursting of thenbsp;rich mines of silver contained in the bosom of the mountains.^

There is probably considerable literature relating to the Black Hills which antedates the middle of the present century, resulting from vari-ons hunting and trapping expeditions and to some extent from earlynbsp;attempts at settlement of the country around their base; also fromnbsp;occasional gold hunting and jirospecting parties that penetrated somenbsp;distance into the interior. But such literature, if it exists, must benbsp;contained in the poimlar journals and newspapers and could scarcelynbsp;be found by the most systematic search. The only mention that I havenbsp;met with belonging to this class is one which very intimately concernsnbsp;the subject of this paper, and is, upon the whole, somewhat remarkable. It is contained in the prose writings of Edgar Allen Poe, andnbsp;occurs in The Thousand-and-Second Tale of Scheherazade. The poet,nbsp;as all know, was in the habit of supjjorting much of his imagerynbsp;by means of footnotes, purporting to be drawn from facts, and oftennbsp;embodying true scientific information. In this characteristic xiroduc-tion occurs the following paragraph:

Leaving this island, we came to another where the forests were of solid stone, and BO hard that they shivered to pieces the finest-tempered axes witli which we endeavored to cut them down.

To this statement he appends a somewhat elaborate footnote, describing three fossil forests. One of these is in Texas, and the description is credited to Kennedy; another is the celebrated fossil forest nearnbsp;Cairo, in Egypt, of which he takes a rather extended account from thenbsp;Asiatic Magazine. Following the first of these accounts by Kennedynbsp;and preceding the longer one relative to the Egyptian forest, he interpolates the following brief but highly significant paragraph:

This account, at first discredited, has since been corroborated by the discovery of a completely petrified forest near the head waters of the Chayenne, or Chiennenbsp;River, which has its source in the Black Hills of the Rocky chain.�

It may never be known when, where, or how Poe came into possession of the data for this statement, but it seems altogether certain that thenbsp;fossil forest referred to is none other than the one that I visited in 1893,nbsp;in company with Professor and Mrs. Jenney, and from which the specimens of wood were collected which are further mentioned in this papernbsp;(infra, pp. 552, 042).

2 The Works of the late Edgar Allan Poe, with Notices of Hi.s Life and Genius,by N. P. Willis, J. E. Lowell, and E. W. Griswold; in two volumes; Vol. I, Tales, New York, 1850, p. 139.

Our knowledge of the Black Hills, in so far as it is based on scientific reports, all bears a later date than any hitherto quoted. The importantnbsp;expedition of Lieutenant Warren, made in the year 1855, did not reachnbsp;the Hills proper, for, as he says, �The routes traversed led over thenbsp;Great Plains between the Missouri, the Platte, and the Shyenne, andnbsp;nowhere entered the mountains.� But the party was in full view of thenbsp;Black Hills, and Lieutenant Warren makes the following remark withnbsp;regard to them: � The Black Hills of �Tebraska are believed to be composed of primitive rock, and are the eastern portion of the greatnbsp;monntaiii belt.� Dr. Hayden accompanied this expedition, and hisnbsp;report follows that of Lieutenant Warren.^ A map accompanies thenbsp;report, showing mnch more fully than had any earlier map the numerous streams that have their origin in the Black Hills. Many fossilsnbsp;were collected on this expedition, some of them Cretaceous, which werenbsp;fully described by Hall and Meek.'*

This was the first of a series of similiar expeditions conducted by the United States Army, each of which made new inroads into thenbsp;nnexplored country. The report of the Secretary of War in 1858 contains Lieutenant Warren�s later results, including eximditions in 1856nbsp;and 1857.�� In these reports Lieutenant Warren gives a historicalnbsp;account of the whole country explored. The Black Hills were penetrated from the south as far as Inyankara, where the expedition wasnbsp;obliged to return on account of hostile Indians and insufficient force.nbsp;Besides giving a tolerably clear description of the geographical position of the Black Hills, Lieutenant Warren makes a number of allusionsnbsp;to the geology, in which the Cretaceous formation is recognized.

Dr. Hayden accompanied each of the expeditions, and his report (pp. 676-747) constitutes the first really scientific contribntion to thenbsp;geology and natural history of the Black Hills. The sectiou of thenbsp;Cretaceous, however, given on page 681, does not come from the Blacknbsp;Hills, but from points near the Missouri Kiver. Nevertheless, in viewnbsp;of its early date, it may be worth while to quote so much of it as refersnbsp;to formation No. 1, afterwards known as the Dakota group:

YellowisR and reddiali friable sandstone, with alternations of dark and wbitish. clays. Seams and beds of impure lignite, fossil wood, impressions of dicotyledonousnbsp;leaves; Solen, Pectunoulus, Cyprina, etc., Lower Cretaceous.

The reference to fossil wood and lignite is significant, as is also the expression �Lower Cretaceous.�

Fossil plants were collected from this horizon and referred tc Dr. Newberry, who did not, however, determine them specifically, butnbsp;referred them to thirteen genera, several of which are extinct. Two

gt;Explorations in tlie Dacota Country in tlie Year 1855, by Lieut. Gr. K. Warren; Washington, 1856. Senate Ex. Doc. No. 76, Thirty-fourth Congress, first session.

sMes.sage from the President of the Dnited States to the two Houses of Congress at the Commence-luent of the Second Session of the Thirty-fifth Congress; Vol. II; Washington, 1858. House of Eepresentatives, Ex. Doc. 170.2, pp. 620ff, 671ff.

of these genera, Oredneria and Ettingsliansenia, are characteristic of the Cenomanian of Europe, and from these and other facts Dr. �Tew-berry argues that the beds can not be Triassic, but must be Cretaceousnbsp;(see pp. 683-684).

By permission of the Secretary of War Dr. Hayden published certain of these results in the Proceedings of the Academy of ISTatural Sciences of Philadelphia for 1857,^ and with the assistance of Mr. F. B.nbsp;Meek, who determined the molluscan remains, he considerably extendednbsp;these observations in a paper immediately following the last.quot;

In the first of these papers, speaking of formation Ho. 1, as seen near the mouth of the Judith Eiver, Dr. Hayden says:

Although the formation of which I am about to speak has already revealed many important facts, the organic contents of its strata differ so materially from those ofnbsp;any other with which I am acquainted in the Northwest, that we are unable to fixnbsp;with certainty its position in the geological scale (p. 116),

The second paper contains considerable introductory matter of a geological character, with sections of the various strata in which thenbsp;fossils were found. On page 128 is given a vertical section of the entirenbsp;region, from the Carboniferous to the Miocene. The description of Cretaceous Ho. 1 is identical with the one already quoted, except that innbsp;place of the words �Lower Cretaceous� the following is substituted:nbsp;� This bed is not positively known to belong to the Cretaceous system.�

On page 125 the authors make the following important statement relative to their formation Ho. 1 �

The deposits above alluded to fat the mouth of Judith River) as probably on a parallel with beds seen near the mouth of Big Sioux River on the Missouri�forming No. 1 of the Nebraska section�are characterized, as stated in one of our formernbsp;papers, by a group of fossils remarkably distinct from those occurring in any of thenbsp;higher Northwestern formations, and there remains some doubt as to whether or notnbsp;they are older than Cretaceous. The presence of the genus Baculites would seem tonbsp;establish the fact that they belong to the Cretaceous epoch j while the occurrence innbsp;the same hand specimens with these remains of Baculites, of a species of Hettangia�nbsp;a genus of bivalves, not known to occur in the Old World in newer formations thannbsp;the Lias�would, on the other hand, indicate that these beds are older than Cretaceous. For the present, however, we express no decided opinion on this point, butnbsp;content ourselves with the remark that we are inclined to think that they hold anbsp;position near the base of the Cretaceous system and are probably on a parallel withnbsp;the Neocomian of the Old World, though they may be older.

�Engineer Department. U. S. Army. Preliminary Report of Explorations in Nebraska and Dakota, in the Years 1855-�56^�57, by Lieut. G.K. Warren. Reprint. Washington, 1875, pp. 1-125, 1 map.

^Explorations under the War Department: notes explanatory of a map and section illustrating the geological structure of the eountry bordering on the Missouri River, from the mouth of thenbsp;Platte River to Fort Benton, in lat. 47� 30' N., long. 110� 30' W., by F. V. Hayden: Proe. Acad. Nat.nbsp;Sci., Phil., Vol. IX, 1857, Philadelphia, 1858, pp. 109-116.

^Descriptions of New Species and Genera of Fossils, collected by Dr. F. Y. Hayden in Nebraska Territory, under the direction of Lieut. G. K. �Yarren, H. S. topograpbical engineer; with somenbsp;remarks on the Tertiary and Cretaceous formations of the Northwest, and the parallelism of the latternbsp;with those of other portions of the United States and Territories, by F. B. Meek and F. V. Hayden;nbsp;loc. cit., pp. 117-118.

Although the weight of evidence thus far favors the conclusion that this lower series is of the age of the lower Green Sand, or Neocomian of the Old World, we yetnbsp;want j)osilire evidence that portions of it may not he older than any part of the Cretaceous system.

In a subsequent paper, published one year later,' the same authors extend these considerations to include their researches in the Blacknbsp;Hills, and this may be regarded as the first scientific treatment of thenbsp;geology of the Black Hills. Relative to their formation Ho. 1, they saynbsp;in this paper:

It will he remembered, we have in all our published papers, when speaking of that portion of the Nebraska section composing No. 1, expressed doubts respecting its age.nbsp;We placed it provisionally as the basis formation of the Cretaceous series, but at thenbsp;same time stated it was not positively known to belong to the Cretaceous systemnbsp;(p.44).

Although we have little direct additiomil evidence at this time in regard to the age of this series, as wo have always understood it, we now know that from beneathnbsp;its lower beds, around the base of the Black Hills, there rises a series of very similarnbsp;strata, as may be seen by the foregoing section, separated from its base by no well-marked line of demarcation, and containing many fossils closely similar to thosenbsp;considered characteristic of the Jurassic system of the Old World. At the samenbsp;time we have failed to recognize amongst these fossils any forms peculiar to thenbsp;Cretaceous epoch, or even very nearly analogous to species common in rocks of thatnbsp;age. .nbsp;nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;.

Inasmuch, however, as numerous leaves beyond a doubt belonging to dicotyledonous trees, closely analogous to the oaks, willows, and other existing forest trees, are known to occur in No. 1 along the Missouri, near the Big Sioux, and in northeasternnbsp;Kansas, and we have a BacuUte from similar beds, apparently of the same age, nearnbsp;the mouth of Judith River, ou the upper Missouri�while we also learn from thenbsp;letters and notes of our deceased friend, Mr. Henry Pratten, that he saw a speciesnbsp;of BaculiU in formations presenting the same characters, and seeming to occupy thenbsp;same position, along the Platte above Fort Laramie, we think we hazard little innbsp;viewing at least a considerable portion of No. 1 as belonging to the Cretaceousnbsp;system.

Another fact favoring the opinion that No. 1, even down as lorv as we have provisionally carried it in the Black Hills section, probably belongs to the Lower Cretaceous, is the occurrence at its base of a bed containing Ammonites and Ostrea, along with Unio, Planorhis, and Paludina-, an association of fossils which, in thatnbsp;position, carries the mind rather to the Wealden than to older formations.

The occurrence of these forms at this horizon also leads us to suspect that a considerable portion of the estuary beds at the mouth of Judith River, above Fort Union, in regard to the age of which we have been so much puzzled, may be, asnbsp;first suggested by Dr. Leidy, a representative of the Wealden, and, as we were thennbsp;inclined to suppose, belong to our No. 1.nbsp;nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;.

1 Descriptions of New Organic Ileniains collected in Nebraska Territory in the year 1857, by Dr. F. V. Hayden, Geologist to the Exploring Expedition under the command of Lieut. G. K. Warren.nbsp;Top. Eng. U. S. Army-, together with some rem.arks on the Geology of the Black Hills and portionsnbsp;of the surrounding country, by F. B. Meek and F. V. Hayden, ibid., Vol. X, Philadelphia, 1859,nbsp;pp. 41-59.

now uiKlerstand it^ near tlie Illack Hills, containing a mingling of fresR-water and. marine fossils, althongh we are not sure any of them are specifically identical withnbsp;those found near the Judith, we me inclined to thinlr our first views iu re**'ard tonbsp;these Judith River formations will prove to be correct, or in other words the bedsnbsp;from which the saurian remains described by Dr. Leidy were obtained will yetnbsp;prove to be a part of the series we include iu No. 1 of the Black Hills section. Thisnbsp;view receives additional support, too, from the fact that the Judith River fresh-waternbsp;or estuary formations were often seen much upheaved and distorted, while aroundnbsp;the Black Hills the Tertiary deposits appear to lie undisturbed upon�the upheavednbsp;older rocks, in such a manner as to indicate that the last period of disturbancenbsp;among the strata of this region occurred after the close of the Cretaceous epochnbsp;but previous to the deposition of the Tertiary (pp. 45, 46).nbsp;nbsp;nbsp;nbsp;�

From all this it is perfectly clear that both Meek and Hayden originally regarded the Dakota group as true Lower Cretaceous, i. e. as lying below the Cenomanian of Europe. Their argument seems tonbsp;have been in the main in the direction of proving that it could not benbsp;lower than Cretaceous, i. e., that it could not be Jurassic or Triassic.nbsp;It is true that the fossil plants, as already indicated by l^ewberry,nbsp;pointed to a Middle Cretaceous age, and not long afterwards quitenbsp;large collections of plants were made and studied by Heer and others,nbsp;who were disposed to place the beds still higher.

But it is also true that the determinations of Meek, Hayden, and Leidy, based entirely on the scanty animal remains, and pointing to thenbsp;Lower Cretaceous, Neocomiau, or VVealden, related to beds in whichnbsp;there were very few if any vegetable remains, and which lay below thenbsp;plant bearing horizon. The plant beds consist of dark brown, highlynbsp;ferruginous sandstone, often becoming clay ironstone, and these stillnbsp;constitute the typical Dakota sandstone. iN^ow the lower beds holdingnbsp;the animal remains do not conform to this description, but are rathernbsp;light colored, coarse sandstones with only occasional yellow ferruginousnbsp;bands. They have a considerable thickness, and there is no antecedentnbsp;improbability in their belonging to a lower horizon.

The next important paper was published four years later by Dr. Hayden,^ but was read July 19, 1861, and is little more than a reelaboration of the subjects treated iu the papers already quotednbsp;from. In this, paper Dr. Hayden continues to refer to No. 1 as Lowernbsp;Cretaceous.

Dr. Hayden accompanied, as geologist, the expedition in charge of Col. William F. Raynolds to explore the head waters of the Yellowstonenbsp;and Missouri rivers, in the years 1859 and 1860. His report was longnbsp;delayed, but appeared in 1869.^ This exjjedition did not, of course, purport to explore the Black Hills, nevertheless they were entered at various points and are dealt with more or less extensively in this report.

'On the Geology and Natural History of the Upper Missouri; Trans. Am. Phil. Soc., Vol. XII, Dew series; Philadelphia, 1863, pp. 1-218, 1 map.

^Geological Keport of the Exploration of the Yellowstone and Missouri rivers, by Dr. F. V. Hayden, assistant, under the direction of Oapt. (now Lieut. Col. and Pvt. Brig. Gen.) \V. F. Kaynolds, Corpsnbsp;of Engineers, 1859-�60; Washington, 1869.

One paragraph relates exclusively to Dakota No. 1, and has more than usual interest iu the present connection;

In the vicinity of the Black Hills, as well as in several other localities, which will he alluded to hereafter in their proper places, are a series of doubtful beds, betweennbsp;the well-marked Jurassic and the Cretaceous, These rocks are quite variable innbsp;their character, sometimes composed, for the most part, of a loose material, clays andnbsp;grits; again of compact concretionary sand or limestones. But few organic remainsnbsp;have as yet been found iu these beds, although the most diligent search has beennbsp;made, and those are quite uncharacteristic, so that their position remains in doubt.nbsp;I have therefore ventured to call them beds of transition, or passage between thenbsp;close of the Jurassic period and the dawn of animal life in the Cretaceous. Thenbsp;locality where the following section of these doubtful beds was taken is near thenbsp;source of the Little Missouri, upon the northeastern side of the Black Hills (pp. 45-46).

Dr. Hayden continued his explorations during the subsequent years, and in 1867 was begun the series of official reports made by him asnbsp;Geologist in Charge of the United States Geological Survey of the Territories. The first of these annual reports, which related to the Territory then embraced in Nebraska, was for the year 1807. Only a smallnbsp;edition of this report was published at the time, and the same is truenbsp;of the two subsequent ones for 1868 and 1809; but in 1873 these threenbsp;reports were republished in a small volume, and it is in this form thatnbsp;they are now usually quoted.' In the first of these reports the Black Hillsnbsp;are scarcely treated, but the general section is reproduced unchangednbsp;from earlier publications. In the report for 1808 the Black Hills receivenbsp;special treatment; their geographical position is carefully indicated, andnbsp;their topographic features described. The geology is also dealt with,nbsp;and the following passages should be siiecially noted:

Tbe geological structure of the Black Hills may be mentioned briefly in this connection. The nucleus or central portion is composed of red feldspathic granite, with a series of metamorphic slates and schists superimposed, and thence upon eachnbsp;side of the axis of elevation the various fossiliferous formations of this region follownbsp;in their order to the summits of the Cretaceous, the whole inclining against thenbsp;granitoid rocks at a greater or less angle. There seems to be no nnconformabilitynbsp;in these fossiliferous rocks from the Potsdam inclusive to the top of the Cretaceous.

From these facts we draw the inference that prior to the elevation of the Black Hills, which must have occurred after the deposition of the Cretaceous rocks, allnbsp;these formations presented an unbroken continuity over the whole area occupied bynbsp;these mountains. This is an important conclusion, and we shall hereafter see itsnbsp;application to other ranges, and also to the Rocky Mountain Range taken in thenbsp;aggregate (pp. 69-70).

Iu tbe report for 1809 Dr. Hayden goes more fully into tbe geological formation, and this report throws great light on the position of thenbsp;low^est Cretaceous beds:

I believe that a thin remnant of this belt extends far south to New Mexico, but it is often so obscured, or so easily concealed, that I have been continually in doubt in

1 First, Second, and Third Annual Reports of the United States Geological Survey of the Territories for the Years 1867,1868, and 1869, under the Department of the Interior; Washington, 1873.

regard to its existence. Coextensive with all the mountain ranges is a large series of beds above the Jurassic belt which belong to the Cretaceous period, the uppernbsp;and middle portions of which are everywhere indicated by characteristic fossilnbsp;remains, as seen on the Missouri River, where they were first studied by Mr. E. B.nbsp;Meek and the writer. The Cretaceous rocks present five well-marked divisions,nbsp;Nos l, 2, 3,4, and 5, or Dakota group. Fort Benton group, Niobrara division. Fortnbsp;Pierre group, and Fox Hill beds. On the Lower Missouri No. 1, or Dakota group, isnbsp;characterized by several species of marine shells and a profusion of impressions ofnbsp;deciduous leaves; but along the margins of the mountain elevations I have nevernbsp;been able to discover a single specimen of organic remains that would establish thenbsp;age of the rocks, I only know that there is a series of beds of remarkable persistency all along the margin of the mountain ranges, holding a position between well-defined Cretaceous No. 2 and Jurassic beds, and in my previous reports I have callednbsp;them transition beds, or No. 1. They consist of a series of layers of yellow and gray,nbsp;more or less fine-grained sandstones and pudding stones, with some intercalated layers of arenaceous clays. In almost all cases there is associated with these beds anbsp;thin series of carbonaceous clays, which sometimes becomes impure coal, and contains masses of silioified wood, etc. On the west side of the Black Hills they assumenbsp;a singularly massive appearance, nearly horizontal, 200 to 250 feet thick, and arenbsp;called Fortification Rocks. Here also occurs a thin bed of carbonaceous clay. Onnbsp;the eastern slope of the Big Horn Mountains I observed this same series of beds innbsp;the summer of 1859, holding a position between Cretaceous No. 2 and the Jurassicnbsp;marls, with a considerable thickness of earthy lignite, large quantities of petrifiednbsp;wood, and numerous large uncharacteristic bones, which Dr. Leidy regarded asnbsp;belonging to some huge saurian.

There are very few points of resemblance between these beds and those which form the Dakota group, as seen in Kansas and Nebraska.

All the evidence therefore that I have had to guide me in regard to these beds along the margin of the mountain ranges has been their position (j)p. 113-114).

Dr. Haj^den�s reports for the years 1870-187-3 relate chiefly to the Great Plains and other parts of the Western country, and we find nonbsp;additional matter bearing directly upon the Black Hills until thenbsp;appearance of Captain Ludlow�s report of the military expedition ofnbsp;1874, which again penetrated this region. The geologist of thisnbsp;expedition was Dr. Isl. H. Winched, and his report follows immediatelynbsp;that of Captain Ludlow.*

Professor Winched gives numerous sections of the strata of the Black Hills at different points, but is very cautious with regard to their correlation with other beds, and I find no indication that he differs fromnbsp;the views expressed by Dr. Hayden with regard to the position of thenbsp;Cretaceous strata, but he does not make use of the sections of Meeknbsp;and Hayden. The legend of the map does not contain any of the general geological terms, such, for example, as Cretaceous, and the bedsnbsp;which were referred to the Dakota group by other authors are herenbsp;simply called � Dakota sandstone.� They are not represented asnbsp;extending entirely around the hills, but are put down in patches alongnbsp;the eastern and western sides and at the southern extremity, with

J Eeport of a Eeconiiaisaance of the Black mils of Dakota, made in the summer of 1874, by �William Ludlow, Captain ot Engineers, Bvt. Lieut. Col., U. S. Army, Chief Engineer, Department of Dakota.nbsp;Washington, 1875. Geological Report, by N. H. Wiuchell, State Geologist of Minnesota, pp. 21-66,nbsp;1 map.

large intervals of uncolored regions. It is evident that Professor Winchell did not observe any subdivision of these beds.

This brings us, in chronologic sequence, to the most important geological survey that has been made of the Black Hills, even down to this date, viz, that of Newton and Jenney, in 1875, the geologicalnbsp;part of which was, unfortunately, not published until 1880.'

The manuscript of this report was iirepared somewhat promptly, and Professor Jenney�s portion, relating to the mineral resources, wasnbsp;published by Congress in 1876, as Senate Executive Document No. 51,nbsp;of the first session of the Forty-fourth Congress, but the geologicalnbsp;report and the rest of the manuscript remained unpublished for fournbsp;years, when it appeared as above, having been revised and edited bynbsp;Mr. C. K. Gilbert. In the biographical notice of Dr. J. S. Newberrynbsp;the origin of the expedition is stated in the following language:

In 1875 tlie Secretary of the Interior applied to Professor Henry, the head of the Smithsonian InstitTition, requesting him to suggest a geologist to take charge of annbsp;exploration of the Black Hills, Dakota, for the purpose of ascertaining the extentnbsp;and value of the gold deposits discovered there. This request was, hy Professornbsp;Henry, referred to me, and in accordance with my nominations Mr. W. P. Jenney wasnbsp;appointed geologist and Mr. 11. Newton his assistant. The purely geological worknbsp;of the expedition was for the most part performed hy Mr. Newton, and the reportnbsp;now committed to you for publication is the result.

Professor Newton�s report on the geology had long been completed and appears to have been in nearly perfect form at the time of his deathnbsp;in 1877. It forms the first part of the volume, occupying 220 pages,nbsp;and the report is accompanied by an atlas containing three maps. Thenbsp;colored geological map is far more complete than any previous map ofnbsp;the Black Hills and shows, as none of the former ones had done, thenbsp;remarkably symmetrical character of their geological relations. Itnbsp;shows first that there is a narrow ring of Potsdam sandstone, then anbsp;wide belt of Carboniferous limestone; next an encircling trough, aptlynbsp;compared by Professor Newton to a moat, of red sandy gypsiferousnbsp;clays, in which is included a purple limestone terrace, all of which isnbsp;supposed to be Triassic, and to be the equivalent of the Eed Beds � ofnbsp;more southern regions. Skirting this is a very narrow border of highlynbsp;fossiliferous light-colored Jurassic clays or marls. Then come the foothills, which consist of Cretaceous sandstones and shales referred by Professor Newton to the Dakota No. 1 of Meek and Hayden�s section.nbsp;These slope back to the dark shales of the Fort Benton group, whichnbsp;are succeeded by higher Cretaceous beds that extend to the plains andnbsp;pass under the Bad Lands of the White Eiver formation.

We are of course concerned here only with the Cretaceous, and strictly speaking only with the lowest member recognized by Professor Newton.nbsp;In his report he takes up the several subdivisions of the Cretaceous in

iReiiort on the Geology and Resources of the Black Hills of Dakota, with Atlas, by Henry Newton and Walter P. Jenney. Dept. lut., U. S. Geog. and Geol. Surv. Rocky Mountain Region, J. W. Powellnbsp;in Charge. Washington, 1880.

their descending order, but nses the numbers of Meek and Hayden. He therefore begins with Ko. 5 (the Fox Hills group), and deals respectively with this, with Ho. 4 (the Fort Pierre group). No. 3 (the Niobraranbsp;group), and No. 2 (the Fort Benton group), concluding with No. 1 (thenbsp;Dakota group), under which he includes all that series of rocks whichnbsp;lie between the black shales of the Fort Benton and the Jurassic beds.

The description of this formation is taken almost literally from the numerous memoirs and reports previously published by Meek and Hayden, and is as follows:

Yellowish, reddish, and occasionally white sandstone, with at places alternations of various-colored clays and beds and seams of impure lignite; also silicified woodnbsp;and great numbers of leaves of the higher types of dicotyledonous trees, with castsnbsp;of rharellaf Dakotensis, Trigonarca Siou2censis, etc. (p. 174).

It will be observed that under localities quoted Professor Newton does not even mention the Black Hills, but proceeds immediately tonbsp;characterize the formation as observed in the Black Hills in the following language:

Black Hills.�Prominently developed, forming the capping rock to the foothills that surround the Hills on all sides, appears with its characteristic composition�nbsp;coarse yellow or red sandstones with discontinuous variegated clays. At places anbsp;considerable thickness of very soft and fine white sandstone appears at the base.nbsp;Elsewhere considerable portions are of hard, dense quartzite. No animal fossilsnbsp;were found, but many remnants of plants�in no case more than mere coaly fragments.

The run of Cretaceous strata which encircles the Hills dips outward on all sides or away from the .axis of upheaval. The strata begin with the foothills that bordernbsp;the outer edge of the valley. The Dakota sandstone, resting conformably uponnbsp;the Jura, forms the capping rock of the foothill ridge, and dips outward at variousnbsp;angles from 10'^ to 40�. Just as the Cretaceous encircles the outcrop of the underlying Jura and Trias, so the different overlying groups of the Cretaceoms�the Fortnbsp;Benton, the Niobrara, the Fort Pierre, and the Fox Hills�succeed each other iu regular order, forming a series of concentric ridges that decrease in altitude as the distance from the Hills increases (p. 175).

Taking up the groups now iu order, the first to describe is the Dakota. Typically it is a coarse sandstone, generally conglomeratic, yellowish in color, and stained red in places by the oxidation of the iron contained in its nodules. Sometimes thenbsp;sandstone is white in color and uniform and fine in texture, and in several placesnbsp;large portions of the formation consist of intensely hard, glassy, and compact quartzite, white or brownish in color, and having the density, toughness, sharjjness, andnbsp;conchoidal fracture of typical flint. The quartzitic development was especiallynbsp;observed at the southern end of the Hills, where the Dakota expaiids into a plateau,nbsp;and in the region north of Warren Teaks, but it is not confined to those localitiesnbsp;(p. 176).

The general relation of these beds to those underlying them in the Black Hills is admirably shown in two sections on pages 140 and 141nbsp;of that volume, which are reproduced below as figs. 117 and 118.

Upon the geological map accompanying this report have been based ail subsequent ones, and very few additions have been made, it isnbsp;reproduced here with very little change except as regards towns, railroads, etc., resulting from the settlement of the country since thatnbsp;date, and may serve as a general index map of that region (seenbsp;PI. Bill).

After the appearance of this report a long interval elapsed before any further special discussion of the geology of tlie Black Hills tooknbsp;place, during which time the country was being rapidly settled and thenbsp;more important locations wei�e being seized iiimn as sites for towns,nbsp;while an agricultural population was gradually encroaching from without. A State school of mines was established at Eapid City and, innbsp;addition to mining interests, some local attention was being paid tonbsp;geology.

In the year 1888 two paj)ers, by P. B. Carpenter and W. O. Crosby, appeared on the geology of the Black Hills, the priority of which 1 liavenbsp;not been able to determine.^

Each of these papers is an important contribution, and that of Mr. Carpenter contains a map in which the drainage and all the important

1 Amphibious Creek is the name given in the (Jeology of the Black Hills to the stream now called Beaver Creek, which in cutting through the rim forms the canyon known as Buffalo Gap. It is unfortunate that the name should have been changed, aa there are several other Beaver Creeks in, thenbsp;Black Hills, and the Board on Geographic Names would do well to restore it.

^Notes on the Geology of the Black Hills, by Franklin R. Carpenter; Preliminary Report of the Dakota School of Mines upon the Geology, Mineral Resources, and Mills of the Black Hills of Dakota.nbsp;Rapid City, 1888, pp. 11-52.

Geology of the Black Hills of Dakota, by W. O. Crosby: Proo. Bost. Soc. Nat. Hist., Yol. XXIII, pp. 488-517. Read March 7, 1888.

towns are shown, as well as the general geology. Some considerable advance as made in the knowledge of the geological formations, but itnbsp;relates principally to the lower beds. The Cretaceous assumes importance only in connection with the discussion of the age of the upliftnbsp;which was formerly supposed to be entirely post-Cretaceous- but evi�nbsp;dence is adduced in these papers to show that much of the materialnbsp;even of the lowest Cretaceous, is derived from the older and more cen�nbsp;tral deposits, which must therefore have been elevated at an earliernbsp;date, ifothing is here said about subdividing the Dakota group ofnbsp;ISTewton, and the matter remained in all respects in its original form

In the summer of 1889 Professor Van Hise, of the U. S Geological Survey, and Mr. C. W. Hall made a �vacation trip into the Black Hillsnbsp;of South Dakota,� and at the meeting of the Minnesota Academy ofnbsp;Natural Sciences on December 3 of that year Mr. Hall read a papernbsp;before that academy, an abstract of which appeared in its proceedLo-snbsp;of that date.' So far as this abstract shows their investigations werenbsp;confined almost exclusively to pre-Cambrian strata, and the Cretaceousnbsp;is not mentioned.

In this rapid survey of the history of the discovery of tlie Cretaceous in the Black Hills and of the Dakota group in general, I have beennbsp;obliged to leave out of account a series of events connected with thenbsp;subject in a general way, but without relation to the Black Hills consisting in the tracing of the Dakota group across the plains from�Min-nesota to Kansas, the discovery of an immense flora and its elaborationnbsp;at the hands of Heer,^ Newberry,= and Lesquereux,-' accompanied bynbsp;an animated discussion as to the age of the Dakota group.

After numerous mistakes, due to conclusions drawn from insufficient material, to the infancy of the science of fossil plants, and to preconceptions based upon Old World geology, a general consensus was at

last reached which placed the Dakota group into substantial correlation with the Cetioinanian of Europe. This view, based almost exclusivelynbsp;on the fossil plants, had become so firmly established that it resultednbsp;in a general feeling that Dr. Hayden, Mr. Meek, and others had madenbsp;a great mistake in referring any of the beds embraced in their �reta-ceous No. 1 to the Lower Cretaceous in any sense other than that theynbsp;were the lowest Cretaceous beds represented in North American geology, and the opinion had come to prevail that there was no Lower Cretaceous in the Eocky Mountain region.

But simultaneously with the latter part of this period investigations in British America, on the Queen Charlotte Islands, in California, innbsp;Texas, and in Virginia had led to the certainty of the existence of truenbsp;Lower Cretaceous beds in each of those regions, and had brought tonbsp;light the Kootanie, the Queen Charlotte group, the Shasta group, thenbsp;Comanche series, and the Potomac formation. I had myself beennbsp;engaged in the study of the Lower Cretaceous flora of the Unitednbsp;States, and especially of the Potomac formation, since the year 1885,nbsp;and had examined a number of the Lower Cretaceous areas in othernbsp;parts of the country. In 1883 I visited the Great Falls of the Missourinbsp;in company with Dr. C. A. White, and I observed that the rocks innbsp;that region which Dr. White, in harmony with the tradition of thenbsp;time, referred to the Dakota group were entirely different in characternbsp;from the well-known brown sandstone which yields the flora of thatnbsp;group, and I even dared to suspect that such a vast thickness of thesenbsp;beds as is displayed on the Upper Missouri could scarcely all belong tonbsp;the Dakota group. In 1888, or thereabouts, Mr. E. S. Williams madenbsp;a collection of fossil plants at the town of Great Falls, which werenbsp;referred to Dr. Newberry for determination and were described by himnbsp;in the year 1891.' He found them to agree in all essential respectsnbsp;with forms of the Kootanie, as made known by Sir William Dawson,nbsp;and thus was established the true Lower Cretaceous age of thesenbsp;deposits. Subsequent discoveries have oidy confirmed this conclusion,nbsp;and considerable additional evidence has been brought to light. Collections made by Knowlton, Peale, and Weed were elaborated by Professor Fontaine,* and in 1895 I visited -the region myself and made anbsp;much larger collection than any of the previous ones, chiefly from Cascade County, some 25 miles southeast of Great Falls, between thenbsp;Little Belt and High Wood Mountains, from coal mines in the samenbsp;formation. This collection has also been studied and reported upon bynbsp;Professor Fontaine, but his report is not yet xmblished. Suffice it tonbsp;say that all this material agrees in supporting the conclusion reachednbsp;by Dr. Newberry as to the substantial identity of this flora with thatnbsp;of the Kootanie beds of British America.

�The flora of tho Great Falls coalfield, Montana, by J. S. Newberry: Am. Jour. Sci., 3d series, Vol. XLI, March, 1891, pp. 191-201, pi. xiv.

* Description of some fossil plants from the Great Falls coal field of Montana, by William M. Fontaine : Proc. U. S. Nat. Mus., Vol. XV, Washington, 1892, pp. 487-495, pis. Ixxxii-lxxxiv,

A somewhat careful study of the flora of the Amboy clays aud of beds of practically the same age on the shores of the Chesapeake Baynbsp;and across the State of Maryland to the Potomac had led me to thenbsp;conclusion that these deposits also lie below the line which shouldnbsp;properly separate the Upper from the Lower Cretaceous. Investigations in Alabama and other Southern States had further shown thenbsp;virtual identity in age of the Tuscaloosa formation and the Amboynbsp;clays. The Comanche series had yielded a few fossil plants, whichnbsp;proved to be at least as old as the oldest Potomac beds.' All thesenbsp;results, taken together, had led me to believe that the true Lower Cretaceous was really very widespread, and that it would be found innbsp;many parts of the West where it had not hitherto been suspected tonbsp;exist.

In the investigation of the Potomac formation in Maryland the subject of fossil cycads had necessarily become prominent, and I arrived at the conclusion that all the trunks of this character that had beennbsp;discovered in Maryland are derived from the older beds, which I callnbsp;the Basal Potomac. Professor Cragin had obtained a fragment fromnbsp;Kansas which certainly belongs to a cycad trunk and which henbsp;described as Cyeadeoidea niunita in 1892.2 He supposed that this fragment came from the Cheyenne sandstone, but after having visited thenbsp;locality I am satisfied that this could not have been the case, and,nbsp;taking all the evidence into account, I am inclined to believe that itnbsp;had weathered out from the base of the true Dakota group, perhapsnbsp;from the Eeeder sandstone.quot;

I mention the cycadean trunks because it was through these that my interest was first attracted to the Black Hills. In Pebruary, 1893, thenbsp;Smithsonian Institution received a letter from Mr. F. H. Cole, at Hotnbsp;Springs, South Dakota, a dealer in specimens, inclosing photographsnbsp;of certain petrifactions found in that vicinity, which he said had beennbsp;called �cycads.� The letter and photographs were referred to me onnbsp;the presumption that these objects were of vegetable origin. I at oncenbsp;perceived that they were fossil cycadean trunks closely resembling �nbsp;those collected by Tyson in 18C0 in the iron-ore clays of Maryland audnbsp;named by Professor Fontaine Tysonia marylandica, and, therefore, alsonbsp;similar to the forms found by Mautell and others in the early part ofnbsp;the century in the Purbeck beds on the Isle of Portland and at othernbsp;points in the south of England. Being greatly interested in the discovery, I recommended that the owner of the fossils be requested tonbsp;send on a specimen for examination. The request was complied with,nbsp;and the specimens proved to be all that I had expected. I thereforenbsp;made the further recommendation that negotiations be entered into

� Notes on some fossil plants from the Trinity division of the Comanche series of Texas, hy William M. Fontaine; Proc. U. S. Nat. Mus., Vol. XVI, Washington, 1893, pp. -261-282, pi. xxxvi-xliii.

2Contributions to the patoontology of the Plains, No. 1, hy F. W. Cragin: Bull. Washburn College Lab. N-at. Hist., Topeka, Vol. II, No. 10,1889, i)p. 65-68.

2 See Mr. C. N. Gould�s paper in Am. Jour. Sci., 4th series, Vol, V, March, 1898, pp. 173,174.

witli a view to the iiurchase of the collection of six specimens, which were offered for sale. This recommendation was also adopted; thenbsp;collection was purchas�d, and arrived in May, 1893.'

Hot Springs is located on the Eed Beds in the valley of the Min-nekahta Creek, or Fall River, and it would have been natural to suppose that the cycad trunks had come either from these or from the Jurassic which borders it had it not been stated that they were fonndnbsp;�on a high hill.� My interest was, of course, strongly aroused to knownbsp;the stratigraphical position of the beds in which they occurred, andnbsp;therefore early in September I made an expedition to the region for thenbsp;purpose of determining it if possible. I had previously correspondednbsp;with Mr. F. H. Cole, of Hot Springs, from whom the specimens hadnbsp;been purchased. I had also written to Professor Jenney, who was thennbsp;at Headwood, and who kindly consented to join me on my arrival andnbsp;aid me in the investigation. After considerable^search and some difficulty the locality was at length found. The details of this expeditionnbsp;are given below (p. 552).

The general resemblance of these cycad trunks to those that have been discovered in various parts of the world in beds below the Middlenbsp;Cretaceous raised the suspicion in my mind that these deposits mightnbsp;be older than the plant-bearing Dakota. I learned while there thatnbsp;Professor McBride had been in that region studying the cycads, andnbsp;that he had collected some and taken them to the State University ofnbsp;Iowa, at Iowa City. In October of that same year he published anbsp;description of a species which he called Bennettites dacotensis.^ Professor McBride, and also Professor Calvin, State geologist of Iowa,nbsp;who had examined the region, presented papers on this subject beforenbsp;the Iowa Academy of Sciences in December, 1893, the latter esj)eciallynbsp;discussing the geological position of the cycads.^ Professor Calvinnbsp;shortly after published the results of his investigations in a communication to the American G-eologist.'* Professor Calvin�s principal objectnbsp;seems to have been to fix the position of the cycad beds relatively tonbsp;the well-recognized formations above and below, and it was not, ofnbsp;course, difficult for him to show that they lay between the Fort Bentonnbsp;shales and the marine Jurassic. The idea that this thick formation,nbsp;amounting in some places to 400 feet, should itself be susceptible tonbsp;subdivision does not seem to have occurred to him, and after considerable discussion of these more general relations, in which he seems tonbsp;realize that he is giving a great breadth to the subject, he concludes innbsp;the following language:

Returning finally to tlie main object for whicb tliese observations were undertaken, it is clear that Bennettites dacotensis McBride belongs to the Cretaceous period,

2A now cycad, by T. H. McBride; Am, Geologist, Vol. XII, October, 1893, pp. 248-250, pi. xi. Reprinted in Bull. Lab. Nat. Hist., State Univ. Iowa, Vol. II, No. 4,1893, pp. 391-393, j)!. xii.

^ Am. Geologist, Vol. XIII, No. 2, February, 1894, pp. 79-84; also published in the Proc. Iowa A.cad. Sci. for 1893, Vol. I, pt. 4; Des Moines, 1894, pp. 18-22.

and the evidence is practically conclusive that the exact horizon at which the individuals of the species were imbedded is represented by the uppermost layers ofnbsp;the Dakota sandstone.

I was wholly unaware of the work that Professors McBride and Calvin were doing, and had overlooked the article of the former in thenbsp;American Geologist for October. On my return from the Black Hillsnbsp;I proceeded to elaborate the results that I had reached, but havingnbsp;much else to do I did not complete the paper until after the middle ofnbsp;February, 1894, when I sent it on to the Journal of Geology, in which itnbsp;soon after appeared.' The substance of that paper will be given undernbsp;the next head.

In all that I said in this paper Professor Jenney concurred, as we were together during the entire investigation, and I sent him thenbsp;manuscript when completed. The sections were made after mutualnbsp;consultation, and in the field, and were reproduced in the article without change. The diagrammatic sections are my own, and are basednbsp;upon the data collected. As stated in that article, we were not satisfiednbsp;with the evidence furnished by the cycads alone or by the cycads andnbsp;the fossil wood, but proceeded to discover beds containing fossil plants,nbsp;both in the lower portion and also in the upper. These two classes ofnbsp;plant-bearing beds differ fundamentally, and the nature of the plantsnbsp;from the lower beds made it practically certain at a glance that theynbsp;could not belong to the plant-bearing Dakota group. But I was notnbsp;satisfied to rest the case upon my own judgment as to these plants. Inbsp;therefore referred them to Professor Fontaine, Avhose thorough familiarity with the older Potomac flora and Mesozoic plants in generalnbsp;has made him the leading authority on the subject. His report uponnbsp;the collection is published in this article, pp. 259-200. The concludingnbsp;paragraph of that report is as follows:

It Avill be seen from this account that the plants, so far as one can judge from such imperfect material, indicate a Lower Cretaceous and Neocomian age, withnbsp;rather more resemhance to the Rome than Potomac phase or grouping, but it is bynbsp;no means certain that the Potomac grouping is not nearest to that here shown.

T also referred the fossil wood to Professor Knowlton, and his report immediately follows tliat of Professor Fontaine, and is in entire harmony with it as regards the Lower Cretaceous age of the specimens.nbsp;Indeed it would naturally seem to point to a still earlier period,nbsp;although it can not be said to prove this.

The specimens from the upper beds were indeutifled by myself, and are fully described and figured below (p. 702-709, Pis. OLX-CLXXII).nbsp;There is no reason to suppose that they do not represent the truenbsp;Dakota group, and the line between the Ujrper and Lower Cretaceousnbsp;must fall somewhere between the cycad beds and the upper plant beds

1 The Cretaceous rim ot the Black Hills, Jour. Geol., Vol. II, Ho. 3; Chicago, April-May, 1894, pp. 250-266.

above the quarry sandstone. Nothing has happened since that paper was published to modify the following statements which it contained:

It thus appears that the flora of the beds above Evans quarrj� is distinctly that of the Dakota group, while all the plants found below that horizon as distinctlynbsp;indicate a Lower Cretaceous age. The force of this evidence is to my mind irresistible, and it is safe to predict that if any other paleontological evidence is evernbsp;found it will confirm this conclusion. The question' still remains as to where thenbsp;dividing line is to be drawn. Between the cycad and fossil wood horizon and thatnbsp;of the Dakota leaves there are some hundred feet of sandstones and shales. Sixtynbsp;to seventy-five feet of this consists of the massive or heavy-bedded building stone,nbsp;which in places becomes flinty and very hard. As the thin shaly layer whichnbsp;separates this from the leaf bed may be safely put with the latter into the Dakotanbsp;proper, and there seems no reason for separating the similarly constituted layer thatnbsp;intervenes between the cycad horizon and the base of the sandstone from the onenbsp;upon which it rests, the question is narrowed down to that of the position of thenbsp;quarry sandstone. That question I will leave to the stratigrax)hical geologistsnbsp;(p. 263).

Professor Todd, State geologist of South Dakota, in 1894 still continued to place the Dakota group between the Jurassic and the Fort Benton, and to indicate the earlier Cretaceous as � absent.� ^ He doesnbsp;not do this in ignorance of the results at which I had arrived, butnbsp;reproduces my sections (pp. 63-71), speaking of one of them as �particularly valuable both for its completeness, and the careful discrimination and measurement of the strata.� Commenting on these sections.nbsp;Professor Todd says:

A point of special interest should be mentioned here, namely, that numerous specimens of cycad trunks have been found at various points. Those which have been quite carefully studied and described by Mr. L. F. Ward (Journal of Geology, 1891),nbsp;of the United States Geological Survey, and Professor McBride (American Geologist,nbsp;1894), of the Iowa State University, were collected in the southern part of the Hills,nbsp;southwest of Minnekahta and southeast of Hot Springs. Specimens also have beennbsp;found several miles north of Rapid City, and in a ravine southwest of that place.nbsp;They all seem to be traceable to the lower layers of the Dakota sandstone, and Mr.nbsp;Ward, partly for this reason, strongly suspects that the lower layers of the so-callednbsp;Dakota formation may be older than that period (pp. 71-72).

This is certainly a very mild statement of my position; and my lan-gui'.ge was intended to express something much more than a strong suspicion as to the Lower Cretaceous age .of these deposits.

But whatever doubts there may have been then, they have all been set completely at rest by subsequent events. During the summer ofnbsp;1894 Professor Jenuey, while operating in the coal-mining district ofnbsp;Hay Creek, Crook County, Wyoming, in the nortliwest portion of thenbsp;Black Hills, but within the Cretaceous rim, found fossil plants in greatnbsp;abundance associated with the coal. True to his instincts as the typenbsp;of a scientific collector, he proceeded to collect these plants, and, as anbsp;pure labor of love, he obtained during the summer and sent to Washington by official mail oueof the finest collections that has thus far been

preliminary report on the geology of South Dakota, by J. E. Todd, State Geologist: South Dakota Geological Survey, Bulletin No. 1, Sioux Falls, 1894, j). 22.

made from any part of the West. They were sent direct to me, and my interest lu them, as may well be imagined, was intense. I receivednbsp;them for the United States Geological Survey, and when they had allnbsp;been unpacked and duly recorded I sent them to Professor Fontainenbsp;for determination. He gave them his painstaking attention, andnbsp;prepared the able report which I embody in this memoir fnn �45-700nbsp;Pis. CLX-OLXIX).nbsp;nbsp;nbsp;nbsp;�

It is needless to anticipate this report further than to say that the plants completely demonstrate the Lower Cretaceous age of the Haynbsp;Creek coal field. Professor Jenney was good enough to make a carefulnbsp;study of the stratigraphical relations of the numerous beds in whichnbsp;the plants occur, representing a large number of horizons, which werenbsp;fully shown in careful sections. At my request Professor Jenney hasnbsp;furnished extensive notes upon his work there, which are embodiednbsp;in this paper, and he has also kindly furnished a map of that region.nbsp;All these data together will, I trust, render the whole subject clear tonbsp;the geologist.

In a revision, which I made in 1894, of the genus Oycadeoidea of Bucklaud, which genus probably embraces all the fossil cycadean trunksnbsp;thus far found in America, I described from notes and sketches madenbsp;by Professor Jenney a new species of that genus, which I called Cnbsp;Jenneyana.^ The description there given was of course very meager�nbsp;and is completed m this paper (pp, 627-632, Pis. CXXI-CXXXII' �

This species was made known to me by Professor Penney, who^�had long been aware of the existence of the two large trunks at the Statenbsp;School of Mines at Rapid City. He had been to the pains to inquirenbsp;into the source of these and had learned that they were collectednbsp;many years before, about 10 miles northwest of Rapid City, by a gentleman named Leedy. Being exceedingly anxious to ascertain whethernbsp;this locality also lies in the Cretaceous rim of the Hills, I went tonbsp;Rapid City early in August, 1895, where I joined Professor Jenneynbsp;and we proceeded to the locality and made a thorough examination ofnbsp;the general region. A more complete account will be found uuder thenbsp;description of the Blackhawk region (infra, pp. 560-563), and I neednbsp;only say here that, as we expected, the beds yielding this specimen lienbsp;above the Jurassic, and the cycads were associated with thj heavynbsp;sandstones which constitute the lowest Cretaceous deposits. Thesenbsp;beds are therefore substantially the same,' in their stratigraphicalnbsp;relations, as those yielding the other cycads and fossil plants alreadynbsp;referred to. Xumerous other specimens had been collected and carriednbsp;away by persons who desired to profit by them, and not one could benbsp;found by our party. Some of these, as will be shown, were subsequently obtained by purchase. A great amount of fossil wood occursnbsp;in that locality, a good collection of which was made.

1 Fossil cycadean trunks of North America, with a revision of the genus Oycadeoidea Bucklaud: Proc. Bjol. Soc- Washington, Vol. IX, Aprii 9,1894, pp, 75-88, (O. Jenneyana is described on p. 87 )

From Kapid City I proceeded to Hot Spriugs, where I obtaiued considerable additional material, some of it from localities already described, but the remarkable trunk which I call Gycadeoidea excelsa, and which isnbsp;described below (p. 037), was collected in an entirely different locality,nbsp;which is fully indicated in connection with the description of the species,nbsp;and its location on the map is given as exactly as the data will permit.

In both my visits to the Black Hills, in 1893 and 1895, I saw large numbers of fossil cycads at various places, mostly in the hands ofnbsp;dealers in specimens, who held them for sale, often at moderate jirices,nbsp;but others were seen in heaps of stones along with specimens of ore, coal,nbsp;building stone, and other products of the country, often symmetrically arranged in iiyramidal forms, at railroad stations and elsewhere.

As the funds at my disposal were limited, I was able to purchase only such as ajipeared to me to represent distinct species, although I wasnbsp;aware that, not having as yet described the species, I might easily benbsp;mistaken in the matter, and that doubtless many new species existednbsp;which could have been easily obtained by anyone who had the means.

Well knowing the fate of most of such material, which usually gets into the hands of private individuals making no pretensions to sciencenbsp;and who wish such specimens merely as curiosities, but who hold themnbsp;in high esteem and are unwilling to part with them, or in most casesnbsp;are so situated that no scientific man ever sees the specimens again, Inbsp;was glad to learn that Professor McBride had himself secured a largenbsp;number of specimens for the State University of Iowa, where I hopednbsp;they would soon be taken up and submitted to thorough scientific study.

But even after he had secured all he desired great numbers remained, and when, the following year. Prof. O. 0. Marsh approached me on thenbsp;subject and manifested a special interest in these objects, I gladlynbsp;imparted to him all the information in my possession relative to the bestnbsp;means of securing them, including the names and addresses of dealersnbsp;who had them for sale, the prices at which they were held, and thenbsp;localities from which they had been collected, so far as these werenbsp;known to me. I greatly hoped that with the resources at his command,nbsp;Professor Marsh would rescue from oblivion and insure to sciencenbsp;many of these interesting paleontological treasures.

I heard nothing further from Professor Marsh until on March 18, 1898, I received a letter from him stating that he had obtained anbsp;large collection of cycads from the Black Hills and requesting me tonbsp;come to Hew Haven and describe them. As the present paper wasnbsp;then already in an advanced stage of preparation and the descrijitionsnbsp;of those in my hands were already written and would be included in it,nbsp;it seemed to me that the opportunity should not be lost of embracingnbsp;under the same head all the new material that might be accessible. Inbsp;therefore immediately consulted with the Director on the subject andnbsp;received orders to proceed at once to New Haven and take all necessarynbsp;notes on Professor Marsh�s collection.

collection consisted of 87 specimens, and notes were taken upon each of these and the more important of them were fully described. Havingnbsp;with me the descriptions of all the other cycads, I paid special attentionnbsp;to characters which could not be observed in the specimens alreadynbsp;described, either because these were too perfect to show any internalnbsp;structure or from defectiveness of any kind. All variations that thenbsp;new material indicated from the specimens previously taken as typesnbsp;of species already identified were also carefully noted, with a view tonbsp;the correction and expansion of the characters. All the new speciesnbsp;were of course very carefully dealt with.

In addition to these notes Professor Marsh placed a photographer at my disposal and all the more important specimens were photographed,nbsp;often from various points of view, for purposes of illustration. Allnbsp;these notes and illustrations appear in their proper places, embodiednbsp;ill the descriptions of the species.

While at New Haven, engaged on this collection. Professor Marsh informed me that two additional invoices were soon expected from thenbsp;Black Hills, and that he wished me to include these also, if possible,nbsp;when they arrived. But I could not then wait for them and returnednbsp;to Washington. On May 20 he telegraphed me that the first invoicenbsp;had arrived, and on May 31 he similarly notified me of the arrival ofnbsp;the second invoice. The two invoices contained 39 specimens, which,nbsp;added to the 87 specimens previously received, constitutes a collectionnbsp;of 12G cycadeaii trunks and fragments.

As nearly all of the first large collection had been obtained from the Miunekahta region, very close to where the original types were discovered, and as these two new invoices were from the Blaekhawk region,nbsp;from which so few cycads had been thus far made known, it wasnbsp;especially important that these should be included in this report, andnbsp;therefore, at a risk of considerable delay, I undertook their elaboration,nbsp;which was accomplished in a little over a week, viz, from June 6 tonbsp;Juue 13, and this included the work of photographing the importantnbsp;specimens. All the data thus secured are embodied in the descriptionsnbsp;below and constitute a very material increase in our knowledge of thenbsp;cyoadean vegetation of the Black Hills Cretaceous.

Nearly all the specimens in the Yale collection were reported either from the Minnekahta region or from the Blaekhawk region, and butnbsp;very little additional information accompanied the collections. Thenbsp;last invoice from the Blaekhawk region was accompanied by data specifying the location of the specimens somewhat in detail, giving distances and direction from Black�s ranch, but this embraced comparatively few specimens. The first invoice contained one specimen whichnbsp;was said to have been found between 2 and 3 miles west of Sturgis,nbsp;South Dakota, a wholly new locality.

With the exception of a small collection obtained by Professor Marsh from Mr. Stillwell, in Deadwood, and reported by him from the Minnekahta region, all of these large collections which Professor Marsh

secured wer� made by Mr. Heury F. Wells, of Sturgis, one of Professor Marsh�s trusted collectors of fossil vertebrates, who bad been induced tonbsp;turn bis attention to a search for cycads, and whose skill as a collectornbsp;readily enabled him to locate the cycad beds and obtain quantities ofnbsp;specimens which had been overlooked by more superficial observers. Inbsp;was certain that Mr. Wells must have covered a considerable area innbsp;his explorations beyond that which I had myself seen or that othernbsp;collectors had visited, and as the work of determining the species proceeded I was more and more imjiressed with the importance of a freshnbsp;survey of the cycad regions, with a view to more exact correlation ofnbsp;the different beds with each other, and a more satisfactory determination of the stratigraphical position of the cycad beds in general. I feltnbsp;that if I could secure the guidance of Mr. Wells to all these localitiesnbsp;this result could be accomplished, and I corresxionded with him uponnbsp;this subject. He expressed a willingness to accompany me to all thenbsp;localities at any time that I might designate.

1 was unable to bring this about until the early part of October, 1898, when, by iirevious arrangement, I met Mr. Wells at Sturgis, and wenbsp;devoted eight days to this work, with very satisfactory results. Wenbsp;first visited the new locality between two and three miles west ofnbsp;Sturgis, where specimen No. 1 of the Yale collection was obtained bynbsp;Mr. Wells. He had found it on a low spur of the foothills, which hadnbsp;dropped or slipped down from the high cliffs to the westward, and wasnbsp;entirely out of position. A second imperfect specimen had been foundnbsp;by him near the same sjmt, and still lay on the surface. Mr. Wellsnbsp;stated that he had explored the cliffs from which these materials hadnbsp;fallen, but had thus far been unable to find any cycads in jmsition.nbsp;We then proceeded to the Blackhawk region and went over all thenbsp;ground covered by his explorations, and later to the Minnekahta region,nbsp;which was examined in the same way.

The more special results of this expedition, including geological sections, will be given under the Minnekahta and Blackhawk regions, resjjectively, but some of the general conclusions arrived at from thisnbsp;examination, which was much more thorough than any that I had previously given to the question, may properly be stated here. It is wellnbsp;known that these Cretaceous sandstones form the foothills surroundingnbsp;the Black Hills, and that they present more or less of an escarpmentnbsp;facing the central core of the hills and separated from the higher andnbsp;more interior uplift by a broad valley occupied by the Bed Beds, whichnbsp;surround the Hills. As a matter of fact, however, the lower part ofnbsp;the escarpment is almost always occupied by beds that are lower thannbsp;the Cretaceous, the base itself consisting of a greater or less thicknessnbsp;of the Bed Beds themselves, succeeded by the whole thickness of thenbsp;Jurassic, which may amount to 150 feet. Upon tins lie the Cretaceousnbsp;sandstones, which, should they be all represented, would form a cliffnbsp;more than 300 feet higher, sometimes making a total of nearly 600 feetnbsp;above the lowest part of the broad encirliug valley.

At one time, of course, alf these materials extended over the area now occupied bj this valley and they have been carried away by the generalnbsp;process of denudation. This process, however, was somewhat peculiarnbsp;in consequence of the large amount of gypsum contained in the Eednbsp;Beds which, as soon as exposed, rapidly disappeared, resulting in anbsp;systematic undermining, as it were, of the cliffs, which gave way alongnbsp;an irregular border and either sank or slipped down so as to occupy atnbsp;different periods positions much lower than that from which they came.nbsp;The further influence of lateral denudation, forming deep canyons in thenbsp;sides of the external wall, resulted in the final formation of a large number of narrow spurs or low sloping ridges, often containing the remainsnbsp;of the original cliffs, practically unchanged, after having sunk down tonbsp;lower positions and still remaining easily identifiable with the cliffs fromnbsp;which they had fallen. The present position of these cliffs, therefore, isnbsp;no indication of their true position, and although this can usually benbsp;determined where large masses have held together, this can not be donenbsp;in case of loose materials that cover the slopes. Here rocks from allnbsp;positions in the Cretaceous series lie mingled together and cover thenbsp;ground to considerable depth, occupying horizons topographically muchnbsp;lower than the base of the Cretaceous. Sometimes these spurs arenbsp;reduced to small mounds, isolated in the red valley, and cycadean trunksnbsp;have been found far out in the middle of the valley on such mounds andnbsp;ridges. Being of a character much more durable than even the hardestnbsp;of the sandstones, they reiuain inta(!t wherever they may happen to be,nbsp;and some have been found lying on top of the Eed Beds themselves, allnbsp;traces of their original matrix having disappeared.

This accounts for a fact that had long puzzled me, viz, the occurrence on many of the cycad trunks of a coating of lime or calcareous matter,nbsp;often turning one side of them pure white aud beiug very firmly cementednbsp;to the rock and difficult to remove. This had led some to suppose thatnbsp;the cycads came oat of the calcareous limestone of the Jurassic. As anbsp;matter of fact it proves nothing, since the greater part of the cycadsnbsp;that have thus far been found have lain iu a position many feet below thenbsp;base of the Cretaceous, often upon the Jurassic limestone, but usuallynbsp;associated with vast quantities of sand rock, which had accompaniednbsp;them in the general settling down of the strata to which they belonged.

It is easy to see from all this how very difficult it is to determine the true position of the cycad beds, especially as they are never foundnbsp;adhering in a natural way to the rock in which they were originallynbsp;embedded, but are always washed out aud found lying in all i)ositions,nbsp;indicative of more or less transportation, or at least local displacement. This is not affected by the fact that nearly all the specimensnbsp;that Mr. Wells has found that were overlooked by other collectors werenbsp;more or less buried iu the ground, only small parts projecting sufficiently for him to recognize their character. The materials iu whichnbsp;they were buried were as heterogeneous as those on the surface, and it

would ofteu require many feet of excavation to reach the original bed upon which these loose materials rested.

There are, however, a few facts which may be taken as constituting evidence as to the position of the cycads.

First, a few specimens have been found, if not actually in xgt;lace or precisely where they grew, at least high up on the original elilF, and itnbsp;is clear that their position must have been at least as high as that innbsp;which they lay.

Second, the cycads and the fossil wood are almost always closely associated, although the latter is much more abundant. Both beingnbsp;silicified, the conditions which would preserve the one would also preserve the other, and therefore it seems probable that both occur atnbsp;pretty much the same horizon. There are a few cases in which the fossil wood has actually been found in place; that is, as erect trunks innbsp;position and prostrate logs projecting from the original cliffs. Thenbsp;fossil wood is not found at all horizons, but only within a certain limitnbsp;of elevation, and it is not believed that the cycads have a wider vertical range than the wood.

Third, both the fossil wood and the cycads, even on the lowest slopes at which they occur, and however far below their original position, arenbsp;usually associated with a certain general class of rocks whose characternbsp;is, sufficiently distinct to make it possible to ascertain their originalnbsp;position, and this is the same class of rocks in which the fossil wood isnbsp;found when seen in place.

All three of these classes of evidence combine and harmonize in fixing the position of the cycad bed, which is always the next important series of rocks that underlie the hard quartzitic sandstones thatnbsp;occupy the uppermost strata, with a thickness of from 75 to 100 feet.nbsp;The cycad and fossil wood bed consists of softer sandstones separatednbsp;by thin beds of shale and is not usually over 50 feet in thickness, butnbsp;may possibly be 75 or 100 feet at some localities.

It may be as well to mention here that on this expedition I took considerable pains to examine the relation of the Cretaceous to the Jurassic, and especially to the uppermost member of the latter, which contains the � Atlautosaurus beds.� I visited the original bed fromnbsp;which bones were first taken, at the foot of Piedmont Butte, and wasnbsp;fortunate in finding Mr. George E. Wieland engaged in taking up thenbsp;bones of a large animal. This spot is 1 mile due east of the town ofnbsp;Piedmont. I measured the bed and found it 54 feet in thickness, andnbsp;the particular horizon at which thebones were then beingexcavated, andnbsp;which had itself a thickness of about C feet, was about 40 feet belownbsp;the top of the Jurassic or base of the Cretaceous. It is a dark claynbsp;shale and at this point rests upon heavy beds of white sandstone. Itnbsp;was impossible to decide, either here or at any other point I examined,nbsp;whether there is unconformity between the Cretaceous and the Jurassic. The particular bed in que.stion is about 100 feet above the bed ofnbsp;Elk Creek and has an elevation above sea level of about 3,400 feet.

As will be seen later, tins bed is therefore about 300 feet below the cycad horizon, and cycads actually occur 4 miles southeast of thatnbsp;place.

The Atlantosaurusbeds, as thus described, are exceediimlv character isticofthe Jurassic of the Black Hills. In my first paper in the Journalnbsp;of Geology� they were accurately described as occupying the unnernbsp;most 50 feet of the Jurassic, although at that time I had no idea thatnbsp;these constituted the Atlantosaurns beds. During the present exnenbsp;dition I examined them at every point where the cycad beds werenbsp;studied and never failed to find them, with almost exactly the san enbsp;character and nearly the same thickness. In many places fossil woodnbsp;occurs in a very fine state of preservation near the summit of thesenbsp;beds and m contact with the Oretaceous, while lignite is the form takennbsp;by the wood when it is preserved in the clay shales immediately belownbsp;They are the same as Xo. 5 of Professor Jenney�s section of the Haynbsp;Creek region, the Beulah clays, of which he gives a full account in hisnbsp;notes published in this paper (infra, pp. 568-593), and many of the feanbsp;tures which I have here mentioned were observed and recorded by himnbsp;When all the facts above stated are taken into consideration thenbsp;difficulties in the way of measuring sections in this region becomenbsp;apparent. It is obviously impossible to reach any reliable conclusionsnbsp;by attempting to make sections of the fallen and disturbed materialsnbsp;that occupy the slopes on the sides toward the broad valleys. Innbsp;most cases it is impossible to say where the Bed Beds end and thenbsp;Jurassic begins or to find the line between the latter and the Cretacenbsp;ous. In order to measure a section in such a region it is thereforenbsp;necessary to find a slope which is not adjacent to a broad valley thatnbsp;is to say, to find some deep canyon a cross section of which will' havenbsp;the form of the letter V and upon the sides of which there has been nonbsp;opportunity for the slow undermining of the cliffs and the resultantnbsp;covering up of the slopes by the materials that have come down fromnbsp;above, but in which there has been a rapid and natural denudation atnbsp;all stages of which the materials liberated have been carried awaynbsp;leaying the surfaces exposed. Such exposures are not easy to find andnbsp;often are not deep enough to embrace the entire thickness of the bedsnbsp;which it is desirable to measure. The section measured by Professornbsp;Jenney and myself in 1893, on the slope of Bed Canyon, was an unusunbsp;ally favorable one, and as will be seen, I was able on this occasion in anbsp;few cases, to find other suitable places and to make sections illustratingnbsp;each of the general regions.nbsp;nbsp;nbsp;nbsp;�

As it was this region which yielded the first cycads, through which my attention was drawn to the general subject, it seems natural to treatnbsp;It first. I include in it all the southern portion of the Black Hills whichnbsp;has thus far yielded any fossil plants, and this is embraced in a rectan-

� Jour, ot Geol., Vol. II, No. 3, ApOl-ilay, 1894, P^S�^cIN^of seotionNoTl,)

gular area having Edgemont for its soutliwestern corner and extending eastward to the Evans quarry, which lies near the middle of the areanbsp;north and south. The accompanying map of this region (PI. LIV),nbsp;which I have had expressly prepared, embraces townshiiis 7 and 8 S.,nbsp;range 3-0 E., lying wholly in Pall Eiver County.

It nearly all lies within the valley of the Minnekahta Eiver, or, as it is now more commonly called. Fall Eiver. The immediate area withinnbsp;which the first cycads were found is very near the divide between thisnbsp;stream and Eed Canyon, while the actual slope on which the most ofnbsp;them occurred is that of a small tributary of Chilsou Creek which fallsnbsp;into the Cheyenne between Edgemont and Cascade Springs.

When I visited this region in 1893 for the purpose of determining the exact location of the cycads purchased of Mr. Cole, as above describednbsp;(p. 512), I proceeded directly to Hot Springs and arrived there on thenbsp;5th of September. Professor Jenney met me there from Deadwood, bynbsp;arrangement. I also found Mr. Cole and arranged with him to accompany us to the locality. An outfit was secured and the 6th and 7th werenbsp;occupied in making this investigation. The locality itself was on ornbsp;near the horse ranch of Messrs. Payne and Arnold, and we securednbsp;the services of Mr. Payne, who was perfectly conversant with all thatnbsp;region, and he took us immediately to the spot. It is about 3 milesnbsp;southwest of Minnekahta Station on the Burlington and Missouri Eail-road, about 1^ miles west of the bed of the small stream abovm mentioned, on the foothills formed by the Cretaceous sandstones. Wenbsp;made a somewhat extended examination of the country round about.nbsp;A mile or more to the northwest of the cycad locality we found thenbsp;divide between that stream and Eed Canyon. Another branch of thenbsp;first-mentioned stream comes into it from the west, and lies to the southnbsp;of our area, which is therefore on a southeast slope and near an abruptnbsp;descent into a canyon. From this point northwest to near the crest ofnbsp;the divide, the highest iioint of which is called Matties Peak on thenbsp;township plat of the General Land Office, the slope is moderate andnbsp;nearly uniform. At the foot of this crest and about miles northwest of the cycad locality occurs an extensive fossil forest. The woodnbsp;is all completely silicified, and consists of prostrate trunks of variousnbsp;sizes and lengths and an abundance of smaller fragments, many ofnbsp;which are scattered about on the sloping plain a long distance belownbsp;the actual horizon at which they were petrified. At tliat horizon manynbsp;still remain, apparently undisturbed, and in one jilace a trunk over 20nbsp;centimeters in diameter was seen projecting several feet from beneathnbsp;the massive sandstone ledge.

To the south of Matties Peak is a saddle, beyond which the crest of the divide is lower, and here the forest is seen to the best advantage.nbsp;The most prominent object is a silicified log over 75 centimeters in diameter and 25 meters long, lying where it fell, which may not have been atnbsp;a very remote date. It had broken away from its roots at the surface ofnbsp;the ground, leaving portions of the stump still exjiosed, and the entire

root could probably be exhumed. Over the area of ground beyond the present trunk, where the upper limbs and branches would naturally havenbsp;been, great numbers of fragments and splinters were scattered clearlynbsp;indicating that many of these branches must have remained attachednbsp;when the tree fell.

It will be noted that all this is within the drainage of the Chevenne Eiver, and therefore it corresponds perfectly with the location of thenbsp;petrified forest described by Edgar Allen Poe, as quoted above (p 509]nbsp;viz, �Near the head waters of the Chayenue, or Chienne Eiver wldchnbsp;has its source in the Black Hills of the Eocky chain.� Of course it isnbsp;possible that there are other fossil forests that would answer thisnbsp;description, but I know of none, and the chances of its being this idennbsp;tical spot are increased by the necessity that it should occur in a geological formation in which petrified forests are to be looked for.^ Itnbsp;could not, therefore, have been in the Bed Beds below nor in the Fortnbsp;Benton above, and the area is restricted to the Lower Pretaceous. Itnbsp;is therefore scarcely possible that he could have referred to any othernbsp;than the forest under consideration. A large amount of silicifled woodnbsp;also occurs at the cycad locality itself, and there is reason to supposenbsp;that the horizon is practically the same. The whole of this reo-iounbsp;including the entire crest of the divide and the area extending to thenbsp;bottom of the canyon of the cycad bed and far to the southeast, consistsnbsp;of the series of hard sandstone that were treated in the Black Hillsnbsp;report as constituting the Dakota group.

The great improbability that the cycads could have lived in Dakota time, or contemporaneously with the flora of the Dakota group led menbsp;to suspect that these beds were below that horizon, and I resolved not tonbsp;leave the field until all the evidence on this point that was attainable hadnbsp;been examined. In the immediate vicinity of the fossil forest and cycadnbsp;bed there were no evidences of plant remains of any other class. Thenbsp;crest above the fossil forest consists of hard, chiefly massive sandstonesnbsp;which may be traced far around the Hills, and form the upper part of thenbsp;abrupt escarpment above the soft Jurassic and the Eed Beds. On thenbsp;inner face of this escarpment it was therefore possible to observe anbsp;great thickness of the Cretaceous in a limited area; and passing overnbsp;this crest a little to the southwest of the fossil forest we entered thenbsp;first lateral canyon which leads into Eed Canyon on the west, so namednbsp;because in it the Eed Beds are well exposed. The escarpment here isnbsp;more or less overgrown with timber, and although the slope is imrynbsp;steep it was possible to work on any part of it. From the summit ofnbsp;Matties Peak to the bottom of the valley was, by careful measurement,nbsp;over 500 feet, but considerably over 200 feet of this was occupied by thenbsp;Jurassic, distinctly marked off from the Cretaceous, while at the verynbsp;bottom the Eed Beds were reached. Above the Jurassic there were aboutnbsp;275 feet of Cretaceous deposits, and on different parts of this slope goodnbsp;exposures occurred, showing considerable variety. It was in thesenbsp;exposures that the search for fossil plants was made, and in one of

CRETACEOUS FORMATION OF THE BLACK HILLS.

them it was successful. This occurred 60 to 75 feet above the Jurassic, and in a number of places imperfect plant remains were found, chieflynbsp;in a soft pink and gray sandstone.

Matties Peak rises some 75 feet above the fossil-forest horizon, and the plant bed now under consideration is about 125 feet below that ofnbsp;the fossil forest. The plants occurred partly in shales and partly innbsp;hard sandstone. They consist chiefly of ferns, and have a facies totallynbsp;different from that of the well-known flora of the Dakota group. Theynbsp;are all carefully described and figured below, and their afiinities wouldnbsp;of themselves be sufficient to make the Lower Cretaceous age of thenbsp;bed that yielded them altogether certain, and it was upon these morenbsp;than upon the cycads or fossil wood that I rested the case in the articlenbsp;above quoted.

The following is the section measured at this place, with a brief description of each bed, giving its thickness in feet. The diagramnbsp;which follows will serve to make the matter still clearer.

As already stated, this region lies very near the divide between the Minnekahta Valley and the Red Canyon, but is really on the slope ofnbsp;Chilson Creek, which makes down into the Cheyenne River a long waynbsp;to the east. At the time I visited this place in 1893 I was under thenbsp;impression that the valley to the east of the eycad beds drained northward into the Minnekahta Valley, and so stated in my article. Butnbsp;this is a mistake, for it is not until we reach the Minnekahta station, atnbsp;the junction of the two railroads, that we find the beginning of thenbsp;Minnekahta drainage. A number of small streams from the west,nbsp;north, and south unite a little way to the eastward and form the Minnekahta or Pall River, whose course is nearly eastward to near Hotnbsp;Springs, a distance of about 15 miles. It flows chiefly over the Rednbsp;Beds, and the Cretaceous escarpment lies to the south, forming a conspicuous east-and-west ridge, with a high point at its western endnbsp;known as Parkers Peak.

On my visit to this region in October, 1898, in company with Mr. Wells, I went carefully over all the ground on which he had obtainednbsp;his sjiecimens. They all came from a region surrounding the originalnbsp;spot which I examined in 1893, and from which so many of the earliernbsp;specimens had been obtained, but Mr. Wells found that there was annbsp;area, irregular in outline and more than a half mile square, over whichnbsp;cycads were strewn, though by no means evenly, as they occurred innbsp;groups at different points, more or less separated from one another.nbsp;This area is all within what is called Bradleys Plat and occupies mostnbsp;of the eastern portion of it. There are three spur ridges running outnbsp;in a southeasterly direction from the main axis, parallel to the line ofnbsp;ray section. The central one is that on which the original cycad bednbsp;is situated, and cycads were found over nearly the whole surface of thisnbsp;ridge, but chiefly on its southwestern slope, a larger number havingnbsp;been obtained from above the original locality than anywhere else.nbsp;The most southwesterly ridge yielded cycads only on its northeasternnbsp;slope, i. e., facing the principal localities of the central ridge. On thenbsp;most northeasterly ridge cycads were more rare, but were sparinglynbsp;distributed over the whole of its lower portion, and it was on this ridgenbsp;that they extended farthest up the slope to the northwest, i. e., in thenbsp;direction of the main axis.

It was evident from a careful examination of these ridges, especially along the slopes of the deep ravines that separate them, that thisnbsp;whole area must be regarded as out of place geologically and as occu-liying its xiresent low j)osition by reason of having settled down in thenbsp;general xirooess of denudation. The disturbance, however, was not sonbsp;great as in most cases of the kind, and many of the rocks seem still tonbsp;remain adhering together in a broad sheet, with occasional ledges innbsp;which relatively they have never been disturbed, and even outcrops ofnbsp;the hard quartzitic masses belonging at the top of the highest ridgesnbsp;were found normally overlying the softer sandstones in the same relative position in which they may be seen on the crest of the divide IJ

miles farther to the northwest. In tlie diagrammatic section, Fig. 119, the dip is purposely exaggerated to represent this late tilting of thenbsp;strata.

I had long been aware that fossil cycads had been found on the south side of the broad valley to the southeast of Minnekahta station. Anbsp;specimen which I saw in a pile of stones at the station was said tonbsp;have come from this region, and I was told that others had been foundnbsp;there. Mr. Wells, learning these facts, had explored the country innbsp;that direction and had obtained a considerable number of specimens,nbsp;one of which is Ho. 5 of the Yale collection, which differs from allnbsp;others in being completely turned to white flint (see infra, p. 603). Thenbsp;various localities at which Mr. Wells secured the specimens werenbsp;visited by me, in company with him, and proved to be of exceptionalnbsp;interest from a geological point of view. The south side of the generalnbsp;Red Bed valley, extending a distance of 6 or 8 miles from Parkersnbsp;Peak eastward, consists of a series of high hills, separated by deepnbsp;ravines, opening into the valley from the south. Toward the westernnbsp;end of this series these canyons have a more and more northwesterlynbsp;course, the last one opening out at the north end of Parkers Peak,nbsp;which is nearly 100 feet higher than the rest and is crowned by thenbsp;quartzitic rocks that overlie the softer sandstones. Ho cycads havenbsp;been found, to my knowledge, on or around Parkers Peak, but at thenbsp;foot of several of the high ridges to the east of it they occur and thenbsp;localities were carefully examined by me. The greater number of thenbsp;cycads of this region, however, were not found near the base of thesenbsp;high ridges but at a considerable distance to the north of them, eithernbsp;on very low ridges extending out into the plain, or on isolated knollsnbsp;that occur at intervals over a considerable part of the broad valleynbsp;itself. These knolls consist of the same soft sandstones that belong atnbsp;the top of the highest hills on the south, and are merely remnantsnbsp;of the materials that were carried away by the process of denudationnbsp;when the valley was excavated. They are all, therefore, entirely outnbsp;of place and their position can only be judged by tlie nature of thenbsp;rocks with which they are associated. In fact, it was here that a considerable number of specimens were found embedded in the red soil atnbsp;the bottom of the valley, in the general vicinity of which there werenbsp;scarcely any remains of the sand rock. Others were deeply entombednbsp;in the imre white sand of the Jurassic, and still others lay upon thenbsp;white calcareous shell rock of that formation and were incrusted withnbsp;a coating of lime.

It seems probable that these heavy cycad trunks may not have been transxmrted any great distance, and the theory that they have rollednbsp;down the slopes of the adjacent hills, at least within any recent period,nbsp;is completely disproved by the great distances at which they occurnbsp;from the foot of the hills, often with lateral ridges between. In allnbsp;probability their original position was not far from vertically over their

present one. It is certain that they belonged to the southern range of hills, because they occur much nearer to the south than to the northnbsp;side of the valley. It must therefore be supposed that the hills andnbsp;chffs along the south side formerly extended over the spot where thenbsp;cycads now occur, and as some of them were found quite close to thenbsp;foot of these hills this whole region may be regarded as a cycad-beariug area. This area occupies a position to the east and southeastnbsp;of Minnekahta, distant from 1 to 3 miles from the station, and covers anbsp;space of nearly two miles square.

The second of the high spurs to the east of Parkers Peak seems to have furnished the larger number of specimens, and they were foundnbsp;on three sides of this hill around its base. I was therefore speciallynbsp;desirous of making a section of this hill, but owing to the difficultiesnbsp;which I have already explained (supra, p. 549), it was impossible to lindnbsp;any point on the north or northwest sides at which this could be done.nbsp;It was clear that the Eed Beds occupied the lower part and that thenbsp;whole of the Jurassic was to be found on the slope, but the sandstonesnbsp;from above so deeply covered the flanks of the ridges that the relativenbsp;thickness of these beds could not be determined. Fortunately, however, a deep gorge had been cut into the side of this projecting ridge,nbsp;having a southwesterly course and opening out into the canyon betweennbsp;this and the next one on the west. This gorge furnished much betternbsp;conditions for the measurement of a section, and this was accomplishednbsp;with considerable success. The bard quartzitic sandstone which formsnbsp;the highest bed is not present on these ridges and the softer sandstonesnbsp;extend entirely to the summit. The following is the section:

7. Rounded summit and slopes at top of ridge, consisting chiedy of soft yellowish or reddish sandstones and thinner sandstone and clay shales, with abundance of fossil wood. This is probably the source of the cycads iihso...nbsp;nbsp;nbsp;nbsp;88

.................................................................

Parkers Peak is the only one of this range of hills which retains the cap of quartzitic sandstones, and it accordingly rises about 100 feetnbsp;above the summits of the several more eastern ridges. Its top formsnbsp;a sort of mesa or elongated table with a north and south trend, and itsnbsp;western face rises directly above the sources of Chilsou Creek and is

nearly in line between the very similar ridge called Matties Peak 4 miles to the westward, which forms the divide between this valley andnbsp;Red Canyon, aad which was the subject of my first section. The greatnbsp;cycad beds of the Minuekahta region lie between these two high points,nbsp;and I therefore thought it very desirable to obtain a section of Parkersnbsp;Peak. This was attended with mauy difliculties and the section is notnbsp;as satisfactory as could be desired, but is as nearly aceurate as it wasnbsp;possible to make it.

Some 10 miles east of Minuekahta station the broad Bed Bed valley gradually closes in to form a canyon narrowing eastward, through whichnbsp;the small stream known as Hot Brook, having its source in numerousnbsp;thermal springs, passes. This at length unites with several othernbsp;branches and forms what is there known as Fall River, on which thenbsp;town of Hot Springs is located. Here the course of the drainage bendsnbsp;southward and breaks through the high ridge on the south, forming anbsp;�gap� through the foothills nearly parallel to Buffalo Gap, 1.1 milesnbsp;northeast of that point. Its course is here southeast, and where itnbsp;enters the hills and forms a deep canyon it affords an excellent secticfunbsp;through the Cretaceous sandstones, with a length of some 4 miles, tonbsp;where it enters the Port Benton clays and ultimately emerges upon thenbsp;plain and joins the Cheyenne River,

The electric-light plant for the town of Hot Springs, some 5 miles distant from it, marks the termination of the Dakota strata, and Evansnbsp;quarry, which is just above this point on the left bank of the stream,nbsp;yields very fine building stone from a massive stratum nearly 60 feetnbsp;thick, containing no organic remains. But immediately over thisnbsp;building-stone stratum occur shales and sandstones in which dicotyledonous leaves had previously been found by Professor Jeuney. It wasnbsp;in consequence of this that he had assumed that the cycads were fromnbsp;the true Dakota group yielding dicotyledonous leaves. But it soonnbsp;became apparent, on visiting the region, that this was not the case andnbsp;that the equivalent of the cycad bed was some distance below the quarry

saudstone wliioh is virtually the equivalent of the massive sandstone forming the crest above the fossil forests.

We made a careful measurement of this section and it was published in my article. In my second visit, in 1895, I could tiud no rea.sou fornbsp;auy essential modifications in that section, and I therefore reproduce itnbsp;here without change. The quarry sandstone dips very rapidly to thenbsp;southeast so as to come down to the bed of the stream at the electric-li^-ht plant and to constitute the rock over which a fine cataract flow�snbsp;at this iioiut and through which the water has worn deep longitudinalnbsp;grooves. Immediately over these rocks there is a bed, some 6 or 8 feetnbsp;in thickness, of dark clay and argillaceous saudstone shales, with carbonaceous matter and some impure coal. In this bed was found a greatnbsp;abundance of more or less comminuted vegetable matter, with shortnbsp;fragments of culms of reed-like plants, which it has not been possible tonbsp;determine. There also occur, iu certain of the shales, a few tolerablynbsp;well-preserved dicotyledonous leaves, some of which have been determined and were sufficient to prove beyond a reasonable doubt that thisnbsp;stratum belqngs to the true Dakota group. A small collection wasnbsp;made near the cataract over the hard sandstone on the right bank ofnbsp;the stream, above the electric-light plant.

This bed was easily followed to the quarry, where it constitutes the overlying mass which it is necessary to remove in order to uncover thenbsp;workable sandstone below. At this point the bed also contains layersnbsp;of soft white sandstone of considerable thickness. Large blocks of thisnbsp;had been thrown down and lay strewn at the foot of the quarry. Onnbsp;the surfaces of these, and more or less scattered through their mass,nbsp;were impressions of dicotyledonous leaves of Dakota types. The shalesnbsp;were also found iu place above the quarry, and some of these yieldednbsp;very good specimens. �Io fossil plants were found in any bed belownbsp;this layer. For a long distance on both sides of the canyon the quarrynbsp;sandstone forms the crest of the ridge, constituting a more or less abruptnbsp;escarpment of from 25 to 75 feet.

Higher up the stream the beds below the quarry sandstone come into view, consisting of softer sandstones, argillaceous shales, and car-bouaceous layers, with impure coal seams, all highly charged withnbsp;guiu. These finally come down to the bed of the stream and arenbsp;ultimately seen restiug upou the Jurassic clays, which in turn overlienbsp;the lied Beds. Some distance below Hot Springs the Cretaceous cannbsp;be seen at the summit of the cliffs with the whole thickness of thenbsp;Jurassic below them and the lied Beds at the base. These latter, atnbsp;and about Hot Spriugs, are overlain by heavy beds of conglomerate,nbsp;probably of Pleistocene age.

11 Grayish black clays with layers of ferruginous concretions, extending to the south fork of the Cheyenne River�contact conformable.

7. Clay shales and sandstones, the latter sometimes white, all plant bearing, much comminuted vegetable matter, matted beds of swamp plants, and

1. Olive-gray, drab, or bluish clays with reddish and yellowish sandstones, to base.

It will be seen by a comparison of these sections that they are in substantial agreement, although no effort was made to make them so.nbsp;The upper member, No. 13, in the section of Matties Peak (supra, p.nbsp;554) probably represents the quarry sandstone of this section, whichnbsp;was considerably thicker at that point, 15 feet more being found, exclusive of erosion; but these rocks were often much harder, and no quartz-itic rocks were seen in the quarry. On account of the debris thrownnbsp;down from the quarry and other obstructions, it was not possible tonbsp;examine the next member below with as much care as was desirable innbsp;view of the fact that it seems to be the equivalent of the cycad andnbsp;fossil-forest horizon; i. e.. No. 12 of that section corresponds to thenbsp;upper 30 feet of No. 4 of the present oue.

in. THE BEACKIIAWK llEGION.

Ill a letter which I received from Professor Jemiey, dated August 28,1893, he gave me the �rst iutimatioii that cy'cadeaii trunks had beennbsp;found in other parts of the Black Hills than the Minnekahta region.nbsp;In that letter he says :

I learned from Professor Carpenter, formerly of the School of Mines at Rapid City, that there is a fine cycad in the collection of that institution. The specimen was

found lying on the surface near Piedmont, South Dakota, a small station on the Fremont and Elkhorn Railroad, some 18 miles north of Rapid City and nearly 50nbsp;miles northeast of Hot Springs. Professor Carpenter tells me that this cycad maynbsp;have been derived from either the .Jurassic or Dakota. Near by are the �Atlanto-saurus� beds in the Jurassic, from which Prof. O. C. Marsh obtained many bones of anbsp;new species of �Atlantosanrus.� Fossil bones, Professor Carpenter (who first discovered these fossils) tells me, are very abundant in the Piedmont locality. Itnbsp;would appear that the cycad-bearing beds, whatever age they may be, encircle thenbsp;Black Hills, so it is probable that other specimens may be found.

Being much interested in this statement, I wrote him at once with regard to it, and his next letter, dated September 22, 1893, containednbsp;the following additional information:

I find that the two specimens of cycads at the School of Mines are in all prob.ability of a different species from those found at Hot Springs. The specimens may belong tonbsp;one individual. One is the dome-shaped termination of a trunk about 15 inches innbsp;diameter; the other appears to be a fragment of the trunk. Compared with the Hotnbsp;Springs variety, the trunk of this is taller, more cylindrical, and the markings of thenbsp;leafstalks rudely pentagonal, seven-eighths to 1 inch in diameter, sometimes irregularly four-sided, not rhombic like those we found. I can not learn the exact horizonnbsp;at which these cycads were found. Some person brought them to Rapid City, wherenbsp;for months they remained in a vacant lot until noticed b.y the dean, who removednbsp;them to the School of Mines. So it is not at all certain that they were originallynbsp;derived from the same or equivalent beds as those yielding cycads at Hot Springs.

In a third communication, dated October 8,1893, on the same subject, after having examined the specimens at the School of Mines and madenbsp;outline sketches of their general form and also of the form and size ofnbsp;the leaf scars, which he kindly inclosed to me. Professor Jenney furthernbsp;states :

Now about the cycad specimens at the School of Mines. After some detective work I have learned that the man who found them is now living in Florida. I have writtennbsp;him to ascertain the exact locality. I hope in a few weeks to have a camera and willnbsp;then photograph the specimens. I inclose a rude outline sketch with measurementsnbsp;of these specimens at the School that will show you the shape; also a sketch showingnbsp;the variations in shape in the leafstalk cells. These specimens differ from the Hotnbsp;Springs species in having a more cylindrical and much taller trunk, free fron excrescences or branches, and in the shape and arrangement of the leafstalks, which arenbsp;in the School specimens imperfectly trigonal, quadrilateral, or pentagonal, andnbsp;frequently strongly winged on two opposite angles. The arrangement of the leafstalk pits on the trunk is not so symmetrical in the concentric spiral lines as exhibited in the Hot Springs species. The leafstalks in the School specimens can be seennbsp;passing entirely through the outer bark of the cycad, a distance of 5 to 6 inches,nbsp;terminating at the pith-like core. It would be possible to break them out in prismatic pieces of flint, the exact cast (?) of the original leafstalk.

I have continued my detective work on the cycad specimens at the School of Mines and have at last traced them back to the man that found them, now at Keuka,nbsp;Florida. In 1877 Mr. J. M. Leedy, of Rapid City, found the cycads in the foothillsnbsp;some 6 or 8 miles north of Rapid City. They remained at his ranch for a long timenbsp;and were taken to Rapid City for exhibition at a fair held in Liberty Hall; were notnbsp;returned, but at the conclusion of the fair were thrown out in a v^acant lot near thenbsp;hall, remaining there several years until removed to the School of Mines. Mr.

Leedy states that he found the specimens north of Box Elder Creek, on the divide between that stream and Elk Creek, and east of the railway (Fremont and Elk-horn), so they would he much nearer Rapid City than Piedmont. I will visit thenbsp;locality soon and try to find more specimens at the same horizon.

Some negotiations were entered into for the loan of the specimens to the United States National Museum, but Professor Jeuney�s connectionnbsp;with the State School of Mines terminated about that time, and as Inbsp;intended to visit tlie Hills again I did not press the matter further then.

As already stated (supra, p. 545), I stopped at Eapid City in the summer of 1895, when on my way to Oregon, Montana, and California,nbsp;arrriving there August 19. I proceeded on the same day to the Statenbsp;School of Mines in company with Professor Jeuney, and through thenbsp;kindness of Dr.V. T. M�Gillycuddy, president of the State School ofnbsp;Mines, I was permitted to examine the specimens about which so muchnbsp;had been said. In the meantime I had described the species* andnbsp;named it Oycadeoidea Jenneyana for Professor Jeimey, my descriptionnbsp;being based on his notes. President M�Gillycuddy very generouslynbsp;consented to the loan of the specimens to the United States Nationalnbsp;Museum, and arrangements were made for their shipment to Washington, where they arrived in due course of events and were here on mynbsp;return from California in the fall. They are thoroughly described andnbsp;illustrated below (pp. G27, 628, Pis. CXXI-CXXV).

The problem was to ascertain the exact locality from which these specimens had been taken, and we spent the rest of the day in makingnbsp;careful inquiries of the citizens of Rapid City and of all persons in thatnbsp;vicinity who were in possession of any information on the subject. Wenbsp;succeeded at length in finding Mr. Gilbert Getchell, a citizen of Eapidnbsp;City, who, although he does not seem to have first found the specimens,nbsp;stated that he accompanied Mr. Leedy at the time that the specimensnbsp;were brought in, visited the spot with him, and assisted him in loadingnbsp;them into the wagon. He offered to accompany us as our guide andnbsp;felt sure that he could show us the exact s^iot. On the next day anbsp;party consisting of Professor and Mrs. Jenney, Mr. Getchell, and myselfnbsp;proceeded to Blackhawk, a station on the Fremont and Elkhoru Eail-road, 7 miles northwest of Eapid City, and there obtained a conveyancenbsp;in which our party visited Black�s ranch, about 2 miles nearly due northnbsp;of the station. It was less than half a mile north of the house onnbsp;Black�s ranch where the cycads lay when Mr. Getchell first saw them.nbsp;Not only this spot but the whole region to the north and northeast wasnbsp;thoroughly explored. No cycads were found, every fragment havingnbsp;been carefully gleaned by other parties, as explained above, but annbsp;abundance of silicified wood, occurred at nearly all points and even atnbsp;the place where the cycads were.

The locality is on the left bank of a ravine which has a southward course and runs past the ranch house. It is a little level opening

below a wooded hill On the hillside, immediately above, fossil wood was more abundant than at any other point. The rocks consist ofnbsp;brown sandstones similar in all essential respects to those of the cvcadnbsp;locality in the Minnekahta region. The level area on which the cvcadsnbsp;lay IS far below the top of the Jurassic, and the sandstones have allnbsp;settled down through erosion of the looser materials from a cousidnbsp;erably higher position.

The above is all that was known of the occurrence of cycads in the Blackhawk region prior to Mr. Wells�s discoveries. His last two innbsp;voices to Professor Marsh contained 39 specimens from that re-vinnnbsp;viz, Kos. 88-126 of the Yale collection, and these were described by m�nbsp;in June, 1898. In the National Museum there are 4 specimens fromnbsp;there. If to these we add the two large trunks that belon�- to the'nbsp;State School of Mines, South Dakota, we have a total of 45 spednbsp;mens from the Blackhawk region, which are treated in this papernbsp;� As, on the occasion of my visit to Black�s ranch in 1895, none of mynbsp;party had been able to discover any additional specimens I wasnbsp;exceedingly curious to know where Mr. Wells had obtained so� lar-e anbsp;number. The labels on the specimens showed nothing beyond \henbsp;fact that they had been found in the Blackhawk region. Professornbsp;Marsh had, however, at my suggestion, impressed Mr. Wells with thenbsp;importance of giving more specific localities for the cycads but sonbsp;late in the day that it was only in case of the last and smallest�invoicenbsp;containing 14 specimens. Nos. 113-126, that Mr. Wells had undertake^nbsp;to be more exact m this matter. All this emphasized the importancenbsp;of my visiting the region again, and under his guidance, minutelynbsp;examining each of the localities. This is what was done in Octobernbsp;1898. A few of the specimens found by him were not far from th�nbsp;locality pointed out by Mr. Getchell as that of the original specimensnbsp;but were somewhat farther up a small ravine, which has a due southnbsp;course and opens into the larger ravine having a southeasterly coursenbsp;that passes by the ranch house. By following up this ravine still farnbsp;ther, we passed over a large number of additional localities and thesenbsp;extended entirely over the divide to the north and northeast All ofnbsp;these specimens occurred out of their natural position, amo�g loosenbsp;rocks that had slipped down from the higher cliffs, and the same isnbsp;true for most of the specimens from the localities farther to the northnbsp;east on comparatively low ground. They had, therefore, no geologicalnbsp;significance and there was no possibility of measuring a section to indinbsp;cate their geologmal position. It was of the utmost importance, however, that a section should be made, and in order to do this I wasnbsp;obliged to explore the high hills to the north, which are in theirnbsp;original position.

About 3 miles due north of Blackhawk and 4 miles southeast of' Piedmont there is a peculiar conformation of the surface, consistingnbsp;of what seems to be, from whatever side it is viewed, a high plateau

rising 300 feet above the valley through which the railroad ]iasses and having a length nearly north and south of about 3 miles and a widthnbsp;of nearly 2 miles. But when one reaches the summit of this highnbsp;hill, one finds that it consists in reality of a sort of gulf or amphitheater,nbsp;not shown on the topograiihic map, with a depth of between 200 andnbsp;300 feet, but having an outlet on the eastern side, and also a depression in its rim on the south side; otherwise it is entirely surroundednbsp;by the high ground covered with the Cretaceous sandstones, has everynbsp;aiipearance of a true basin, and I�eaches at the highest points the 3,900-foot contour line. The uppermost rocks are somewhat quartzitic andnbsp;barren, usually forming precipitous ledges, but the next terrace belownbsp;consists of the typical soft sandstones with which the fossil wood andnbsp;cycads are usually associated and are found mingled with them on thenbsp;spurs and slopes below. In this particular case, however, it has fortunately happened that a number of cycads, and among them some ofnbsp;the largest and most interesting, were found virtually in place at thisnbsp;high level on the inner slope of the rim of this basin at its southernnbsp;end. Mr. Wieland had also found a specimen on the west side at thenbsp;same level and another half a :nile north of the basin at a little lowernbsp;level. The discovery of these specimens is very important in confirming the view at which I had previously arrived, that this highest terrace below the quartzitic cap constituted the cycad horizon. In fact itnbsp;demonstrates this, at least for the Blackhawk region.

I therefore determined to make a section at the precise point at which these cycads occurred. It was impossible to obtain this fromnbsp;the south side on account of the gradual slope and the numbef of slii)Snbsp;which obscured the strata, and I Avas obliged to go over on the inside ofnbsp;the basin at its extreme southern end and measure the section fromnbsp;that side. Owing to the size of this inclosed valley, however, some ofnbsp;the same difficulties presented themselves that occur in cases wherenbsp;broad valleys are adjacent to the slopes, and it was impossible to measure the thickness of the Jurassic or even to find its contact with thenbsp;Bed Beds, if the latter occur at all. The following is the section asnbsp;thus measured:

4. Soft, yellowish sandstone and sandstone shales with occasional reddish clay seams, especially near tlie base; cycads found in place within 6 feet of

the BLACKHAWR region of black hills south DAKOTA

The largest cycad from that regiou, �To. 100 of the Yale collection, and the largest but one in the world, was found at a height of 110 feetnbsp;above the Jurassic contact or 80 feet below the top of the highestnbsp;crest on the south end of this basin on its inner slope, and severalnbsp;other of the most interesting specimens were found either near this ornbsp;in relatively the same position somewhat farther east.

A less successful attempt was made to measure a section at the north end of the basin, where the rim was found to rise 86 feet above thenbsp;top of the Jurassic, e.xposed below. But it is probable that the highest part of the rim here is considerably below the cycad horizon andnbsp;the plain slopes away to the northward, so that no full section cannbsp;be obtained. On the west side, where Mr. Wieland found a cycad atnbsp;about the same horizon as those at the south end, the rim is very thinnbsp;and the rocks have the appearance of dipping raxiidly to the westward.nbsp;This is, however, undoubtedly due to the effect of undermining andnbsp;tilting them at the time that the broad valley on the west was beingnbsp;eroded. On the slope toward the basin the dip is in the op])ositenbsp;direction, doubtless from a similar cause.

The entire cycad area therefore of the Blackhawk region, as we now understand it, forms a sort of rectangle about a mile and a half widenbsp;east and west and 3 miles long north and south, with Black�s ranch atnbsp;its southwestern corner, and it extends in altitude from the 3,600- to thenbsp;3,750-toot contour line (see map, PI. LV). All the specimens, however, found below the 3,750-foot contour line are of course out of place.

After Professor Jenney and I had discovered, in 1893, that there was a large series of beds underlying the true Dakota grouj) in the Blacknbsp;Hills, the idea of developing an extensive fossil flora assumed a definitenbsp;shape in the minds of both of us. His iirolonged investigations in allnbsp;liarts of the Black Hills in the capacity of a mining expert rendered itnbsp;highly probable that if such a flora existed he would sometime find itnbsp;when studying such outcrops as jiromised to yield coal. An occasionnbsp;of this kind presented itself much earlier than I had expected, when,nbsp;the following year, he was employed by the railroad companies to investigate the coal fields on Hay Creek, a tributary of the Belle Fourche,nbsp;which rises in Crook County, Wyoming, and flows slightly northnbsp;of east, joining the Belle Fourche opposite the town of that name.nbsp;Valuable beds of coal were discovered on the upper tributaries of Haynbsp;Creek, and this general regiou is now known as the Hay Creek coalnbsp;field, with Barrett post-office near its center. The map (PI. LYI)nbsp;shows in detail the nature of the Hay Creek coal field, and indicatesnbsp;the stratigraphy, as worked out by Professor Jenney, and all thenbsp;localities from which fossil plants were obtained by him and sectionsnbsp;made.

The history of Professor Jenney�s investigations will now be given. In June, 1894,1 received a letter from him dated June 10, from whichnbsp;I give the following extract:

I have just returned from a three weeks� camping expedition in the foothills of the eastern part of the Bear Lodge Range. I had occasion to study carefully thenbsp;Hay Creek coal field, situated 40 miles northwest of Deadwood, and have measurednbsp;many sections covering the Dakota group of Newton. I found much that wouldnbsp;interest you. It is true I could not find any cycad trunks, hut think we will yetnbsp;find impressions of the leaves. Fossil wood is quite abundant in this formation. Innbsp;one place a huge tree is sticking in the face of a cliff; the trunk is 3 feet in diameternbsp;and extends along the face of the cliff for 40 or 50 feet�, forming across the rifts innbsp;the rock a kind of natural bridge. I could only take specimens of the sapwood andnbsp;heartwood of this silicified trunk. It is too large to send to Washington.

I find in the Hay Creek district four distinct plant-bearing horizons that will prove very useful in separating the Dakota group into the different epochs. I couldnbsp;only collect a few plants from each, but have carefully recorded the localities.nbsp;Several will, if worked, yield, I am satisfied, finely preserved plants. It is true Inbsp;have not found in the Lower Cretaceous a great variety of plants, and that goodnbsp;specimens are not common.

I discovered between the Jurassic and the Dakota group of Newton evidences of unconformity, i. e., that the Jurassic formation had suffered considerable erosionnbsp;prior to the deposition of the Cretaceous. Further, between the top of the Jurassicnbsp;beds with characteristic marine fossils and the base of Newton�s Dakota groupnbsp;there are about 50 feet of beds as to which I am as yet unable to determine whethernbsp;they should be classed as Jurassic or as Lower Cretaceous. These beds are ash-graynbsp;clays with calcareous clay nodules, apparently without fossils. At the top of thisnbsp;undetermined series of beds and just beneath the sandstone shales with plantnbsp;remains, the supposed base of the Cretaceous, occurs a bone-bearing bed, fromnbsp;which I obtained fragments of fossil rib bones 2i inches wide, I to 1 inch thick.nbsp;The �Atlantosaurus� beds of Professor Marsh, that Professor Carpenter states werenbsp;identified by him near Piedmont, South Dakota, at once came to mind.

I hope to have time to search the locality and its vicinity and determine the horizon of these animal remains.

To return to the Dakota of Newton, I find it naturally separates into the following (this is of course subject to future discovery and to the determination of the plantsnbsp;of the several horizons):

1. nbsp;nbsp;nbsp;The Dakota sandstone with characteristic plant remains. The base a

massive sandstone of variable character with respect to hardness, percentage of iron, etc.................................................... 100

2. nbsp;nbsp;nbsp;Clay shales, sandstone shales, and soft sandstones with, locally, beds of car

bonaceous shale and plant remains, plants, ferns of modern type, and ribbon-like fucoids; at base of this member a massive cross-beddednbsp;sandstone 50 feet in thickness; contact stratum, a breccia of clay andnbsp;sandstone marking unconformity....................................... 150

3. nbsp;nbsp;nbsp;Massive sandstone 40 feet, underlain by drab clay shales and carbonaceous

shales with plant remains. Plants, ferns, cycad-like in type, pine needles, plant impressions like modern Equisetum, leaves of willows,nbsp;rushes, etc............................................................. 100

4. nbsp;nbsp;nbsp;Soft sandstones, clay shales and clays with one workable (3 to 5 feet thick)

aud several smaller local seams of coal, plant remains, peculiar ferns, cycad-like, and long flattenednbsp;nbsp;nbsp;nbsp;pine needles.............................. 100

Ii\Y(]m':EKliEGION

BLAGKIIIUS

5. nbsp;nbsp;nbsp;Ash-colored clays with calcareous nodules. No fossils observed; near top

6. nbsp;nbsp;nbsp;Jurassic clays and shell limestone with marine fossils�Belemnites. Ostrea,

Professor Jenney coinmenced almost immediately to send on packages of fossil plants. Three packages were sent on June 16, two on Junenbsp;28, five on July 8, and one on July 12. In addition to this, he sent anbsp;box containing specimens collected in August and September,nbsp;Altogether the collection is one of the finest that has ever been madenbsp;from any part of the West. It came in admirable condition, withnbsp;every siiecimen carefully and accurately labeled, indicating its localitynbsp;and the particular stratum from which it was obtained. This collection was forwarded to Professor Fontaine for determination, and hisnbsp;report upon it is embodied in this paper (pp. 645-702, Pis. CLXII-CLXIX).

In one of Professor Jeimey�s letters, dated August 20,1894, he gives the following additional facts, which are well worth recording:

I hope the collections I have sent in will insure the determination of the age of the coal and the separation of Newton�s Dakota group into its several horizons. Sincenbsp;my last letter I have done a great deal of detailed stratigraphic work in the'intervalnbsp;between the Red Beds and the Fort Benton shale.

I find overlying the marine beds of the .Jurassic about 50 feet of light-colored clays with nodular layers of clay limestones. These beds I first supposed to be possibly^ Lower Cretaceous, and marked them No. 5 in the section I sent you in my letter.nbsp;I have found evidences tliat these beds are probably Jurassic shallow-water deposits;nbsp;they carry often large trunks and limbs of fossil wood, and in the layers of impurenbsp;limestone a few small Ammonites near the top of these beds; just below the contactnbsp;with the base of No. 4, Cretaceous, occurs a bone-hearing bed�large elongatednbsp;vertebra! and fragments of leg and thigh bones, all in a poor state of preservation.nbsp;These beds recall the Atlantosaurus beds of Marsh to my memory, but as I have notnbsp;the original papers by Professor Marsh on those saurian remains I can not say morenbsp;as to their probable place in the section.

There are evidences that the land was rising at the close of the Jurassic, for some of the No. 5 beds may be brackish or fresh water, and that before the deposition ofnbsp;the lowest beds of the coal series (division No. 4, Newton�s Dakota) the land wasnbsp;above water and had suffered a quite extensive denudation, and that the workablenbsp;and lowest beds of coal were deposited in basins, channels, and valleys in the erodednbsp;Jurassic. This I believe has not been noted before. I find the dynamic geology ofnbsp;the region far more complicated as I study it than was at first apparent. There arenbsp;faults, elevations of strata, both anterior and subsequent to the formation of the coal.nbsp;I have been able to send you quite a representative collection of the plants of No. 2nbsp;division of Newton�s Dakota; a less extensive one of the plants of No. 3 division,nbsp;and but few plants from No. 4 division, the horizon of the coal. I did not try tonbsp;collect from No. 1, the Dakota sandstone proper, as the plants from that horizon arenbsp;well known. I have hired three or four miners, and will open the coal in No. 4, in anbsp;new field I have discovered in an unexplored section of this region. If there arenbsp;any plants I will send you collections made.

As I think I wrote you, I find evidences of unconformity between No, 3 and No. 2 and between No, 2 and No. 1. I have been unable to detect any unconformitynbsp;between No. 4 and No. 3. The great unconformity of the Jurassic and No. 4 has beennbsp;noted. On the higher ridges of Jurassic surface, No. 3 rests on the Jura and No, 4nbsp;is absent.

CRETACEOUS FORMATION OP THE BLACK HILLS.

I think I can get yon plants that will show No. 4 to he older and distinct from No. 3, though the stratigraphy shows apparent uninterrupted deposition.

Not content with performing these important services, Professor Jenneyhas taken time to prejiare for me, with permission to use in thisnbsp;report, an extended series of notes upon the Hay Creek region and anbsp;large number of sections from the most important jilant-bearing beds.nbsp;It is with great pleasure that I avail myself of the data thus furnished,nbsp;which I insert bodily into this memoir. The map of the Hay Creeknbsp;coal field was also prepared by him; and taking this in connection withnbsp;his descriptions and sections, we have a very full statement of thenbsp;geology and paleontology of that region.

Professor Jenney continued to furnish these notes down almost to the time of going to press. It is my duty to add that he has performed all these services for the pure love of science, and the spirit bynbsp;which he has been actuated may be gathered from the followingnbsp;remark in his letter of April 17, 1898, inclosing the last of his manuscript, where he says:

Use these notes when you can in writing, and all other notes, maps, and data sent. Do not worry about giving me credit. The object to he attained is the bestnbsp;monograph on the coal field. So use all data as your own and publish over yournbsp;own signature, unless there is good reason for not doing so. You have full authoritynbsp;to omit, change, or publish any or all of the material sent in such manner as younbsp;shall deem best.

A copy of Professor Fontaine�s manuscript describing the fossil plants of the Hay Creek coal field was sent to Professor Jenney, andnbsp;his notes include a discussion of the stratigraphy from the paleontological standpoint.

In the report on the geology of the Black Hills based on the field work of the survey of that region made in 1875, Mr. Henry Newton,nbsp;the geologist of the survey, wrote:

It has already been remarked that the concentration of attention on the main body of the Hills prevented a thorough study of the Jura. In a still greaternbsp;degree it reduced our opportunities for the examination of the Cretaceous. Verynbsp;few of onr excursions penetrated more than the basal member, and the only examinations of the entire series were in onr rapid approach to the Hills via Beavernbsp;Creek and on our return inarch. So far, however, as our observations extended, itnbsp;was evident that the Upper Missouri section of Meek and Hayden was applicablenbsp;without essential modification.¹

Mr. Newton quotes from the Invertebrate Paleontology of Professor Meek as follows;

Yellowish, reddish, and occasionally white sandstone, with at places alternations of various-colored clays and beds and seams of impure lignite; also silieified wood,

and great numbers of leaves of the higher types of dicotyledonous trees, with casts otPharella? DaJcotensis, Trigonarca Siouxensis, Cyrena arenarea, Margaritana Nebras-censis, etc.

Localities.�Hills back of the town of Dakota; also extensively developed in the surrounding country in Dakota County [Nebraska] below the mouth of the Bignbsp;Sioux River, and thence extending southward into northeastern Kansas and beyond.nbsp;Thickness, 400 feet,'

Mr. Ifewtoa, writing from liis own observations on the Dakota group in the Black Hills, describes it as follows:

Prominently developed, forming the capping rock to the foothills that surround the Hills on all sides; appears with its characteristic composition�coarse yellow ornbsp;red sandstones with discontinuous variegated clays. 'At places a considerable thickness of very soft and line white sandstone appears at the base. Elsewhere considerable portions are of hard, dense quartzite. No animal fossils were found, but manynbsp;remnants of plants�in no case more than mere coaly fragments. Thickness, 250 tonbsp;400 feet.'^

Mr. Newton placed in the Dakota group all the sandstones and clays included between the Jurassic and the Port Benton, following Dr. F.nbsp;y. Hayden, who had studied this formation along the Missouri Eiver,nbsp;and who first identified the Dakota sandstone in the Black Hills, Dr.nbsp;Hayden having accompanied as naturalist and geologist the expeditionsnbsp;under command of Gen. G. K. Warren in 1855 and of Gapt. W. P.nbsp;Bayholds in 1859, who made brief visits to the Black Hills.

Mr. Newton has in the text quoted briefly explained the imperfect and hurried character of the iuvestigatiou of the later geological formations in the foothills, which was unavoidable from the necessity ofnbsp;concentrating the work upon the metamorphic region of the interior ofnbsp;the Hills, with its placer gravels and gold-bearing veins.

In the summer of 1877 Mr. Newton returned to the Black Hills for the purpose of making a more complete investigation of the geologicalnbsp;structure and to supply many omissions in the field observations madenbsp;in 1875. While there engaged he died at Deadwood from typhoidnbsp;fever. The manuscript of his report on the geology of the Black Hillsnbsp;was left incomplete at his death aud was not published until 1880.

From the early work of Dr. Hayden in this region the unity of the Dakota group was not questioned until the visit of Prof. Lester F.nbsp;Ward in September, 1893, who came to the Hills with the object ofnbsp;determining, if possible, the horizon of the remarkable fossil tranks ofnbsp;cycads found near Hot Springs, South Dakota. In the search for thenbsp;cycad locality aud in the approximate determination of the horizon fromnbsp;which these fossil trunks had been derived I accomiianied Professornbsp;Ward, as related elsewhere.

The following summer I was engaged in an investigation of the economic value of the coal of the Hay Creek region in the extremenbsp;northern Hills, distant 90 miles north-northwest from Hot Springs. Innbsp;the progress of the field work it was found that workable beds of coalnbsp;occurred in the lower part of the Dakota group. Later, as the relation

of tlie different beds was worked out, and as collections were made of the fossil plants, it became apparent that the Dakota group was madenbsp;up of a number of distinct formations, separable stratigraphically, andnbsp;that each division was characterized by a fossil flora peculiar to itself,nbsp;by which it could be readily recognized. The collections of fossil plantsnbsp;were forwarded for determination to Professor Ward at Washington.nbsp;There was also sent a general section of the strata exposed in the Haynbsp;Creek region, a description of the several divisions determined stratigraphically of the Dakota group, and a statement of the approximatenbsp;position of each plant-bearing bed or horizon, referred to its propernbsp;division and measured from the Jurassic below and also from thenbsp;Dakota sandstone above.

These plant collections, with the accompanying notes, were referred by Professor Ward to Prof. Win. M. Fontaine for examination.

The divisions of the Dakota group, determined stratigraphically, were confirmed by the study of the plants by Professor Fontaine, whonbsp;further determined that the divisions (Nos. 3 and 4) lying at the basenbsp;of the Dakota group, and including the coal beds of economic importance corresponded most nearly in flora to the Lower Potomac. Thenbsp;division above (No. 2), lying immediately beneath the Dakota sandstonenbsp;(No. 1), was correlated by its flora substantially with the upper portionnbsp;of the Older Potomac (Aquia Creek series), and all of the Dakota groupnbsp;included between the Jurassic at its base and the true Dakota sandstone at the top was thus placed in the Lower Cretaceous.

In the determination of the horizon of the fossil cycads in the Hot Springs region Professor Ward had previously identified the upper 100nbsp;feet of strata of the Dakota group as constituting the Dakota sandstone proper, characterized in the southern hills by an abundance ofnbsp;well-preserved dicotyledonous leaves. The underlying beds includednbsp;between the Jurassic and the Dakota sandstone were shown to be innbsp;all probability Lower Cretaceous, from position, from the abundance ofnbsp;fossil cycad trunks, and from the confirmatory evidence of a small collection of fossil plants obtained.

The field work in the Hay Creek region and the plant collections made have furnished data for the division of the Dakota group intonbsp;distinct epochs, corresponding to the prominent divisions of the Cretaceous of the Atlantic coast. Further, it has made certain the determination by Professor Ward of the Lower Cretaceous age of the largernbsp;part of the strata in the Black Hills heretofore included in the Dakotanbsp;group.

1. Character of the sediments.�The beds forming the Dakota group of Newton are either pure sands, clays, or mixtures of clay and sand.nbsp;Granitic sands (arkose) are absent. These sediments are consolidatednbsp;into rook strata of varying hardness. The sands form sandstone in

many localities, particularly in the lower part of the Dakota sandstone, of a quality suitable for building purposes. The clays occur as claynbsp;shales, save the uuder and over clays of the coal beds, which are commonly soft fire clays, though with a shaly structure.

The beds show little or no disturbance after deposition. Erosion has taken place in certain beds prior to the deposition of the later stratanbsp;resting upon them. The clay balls and lenses�irregular masses andnbsp;sheets of clay described as occurring in the Potomac formation, the resultnbsp;of the destruction of preexisting clay beds�do not seem to have theirnbsp;counterpart in the Black Hills. So far as the writer has had the opportunity to examine the Dakota formation in other localities in the beltnbsp;encircling the Black Hills, it everywhere has the above-describednbsp;character.

2. Persistence of plant horizons.�Certain horizons carry plants throughout the Hay Creek region; notably the plant horizon of division ISTo. 3 at the base of the cliff-forming sandstone (No. 3); also thenbsp;bed of carbonaceous shales about 100 feet below the base of the Dakotanbsp;sandstone in division No. 2.

3 The Lower Cretaceous a coalforming period in the Blade Hills.� At the opening of the Lower Cretaceous the beds of workable coal werenbsp;deposited in hollows eroded in the Jurassic surface. A period of quietnbsp;must then have occurred, long enough to form coal with a thickness ofnbsp;from 3 to 6 feet. The coal appears to have been formed where thenbsp;vegetation grew and to have been deposited in basins, channels, andnbsp;small irregular swampy tracts between the Jurassic hills.

Like the coal beds of the Carboniferous, the Hay Creek coals have an under clay, filled with fragments of plant remains, and an overclay, in which occur, in favorable localities, well-preserved plants. Overlying and capping the clays with the included coal are thick beds ofnbsp;sandstone.

In division No. 3 thin coals occur, but are seldom found of workable thickness. In division No. 2 a bed of black carbonaceous shale occursnbsp;continuously over a considerable area. In the Dakota sandstone thinnbsp;impure coal seams without economic value are found in the upper shalynbsp;strata.

4. The Newcastle coal.�At Newcastle, Wyoming, at the Cambria coal mines, on the southwestern border of the Black Hills, coal also occursnbsp;in the lowest beds of the Lower Cretaceous. The horizon of the Newcastle coal is about 50 feet above the top of the Jurassic. The coal isnbsp;peculiar in character, having been apparently deposited in the bottomnbsp;of a lake, and formed mainly from the leaves of some species of conifer.nbsp;The coal is underlain by hard, massive sandstone and is directly coverednbsp;by thick sandstone strata, without a trace of the underclay or overclay commonly occurring with coal beds the world over.

At the Cambria mines this coal is 7 to 9 feet in thickness. Seams of splint, or impure coal, 4 to 8 inches thick, occur in the upper part of thenbsp;bed. On weathering on the slack dump the fragments of these splint

layers disintegrate intobunclies of long, flat, pine needles, brown colored on the surface; on breaking, of a brilliant jet-black coal within. Thesenbsp;conifer leaves are 3 to 4 inches long, and as a result of one or twonbsp;seasons� exposure to weather a fragment of splint comes to resemble anbsp;bunch of coarse brown-colored hay. These needles will burn whennbsp;lighted with a match.

The Newcastle coal is heavy, dense, breaking into shaly fragments, thin at the edges, like rock spalls from a quarry. The ash is nearlynbsp;pure silica, apparently made up mostly of fine sand deposited with thenbsp;vegetable matter forming the coal. The percentage of ash varies widelynbsp;in different parts of the coal bed, but averages about 13 to 18 per centnbsp;of the weight of the coal shipped. In coking, this lt;;oal gives off a largenbsp;amount of condensable products�tar, ammonia, etc.

The Newcastle coal is used on the locomotives of the Burlington Eail-road, as a fuel for steam boilers at the Homestake mines, and in the form of coke in the smelting furnaces (D. amp; D. Smelter) at Deadwood,nbsp;South Dakota. It is not favored as domestic fuel. Microscopic examination of specimens of this peculiar coal from different parts of the bednbsp;might throw light on its origin and formation.

5. Stratigraphical position of the Lower Cretaceous in the Blade Hills.� Most valuable of all is the precisely defined position of the Lowernbsp;Cretaceous. The Dakota group of Newton embraced all the stratanbsp;included between the marine Jurassic and the Fort Benton of the Uppernbsp;Cretaceous. The marine Jurassic is characterized in the Black Hillsnbsp;by a great abundance of fossil mollusks, so that the age of the formation is well established. Besting uncomformably on the marine Jurassic, and formed from the products of its erosion, is the brackish or freshwater formation whicli I have designated as later Jurassic, divisionnbsp;No. 5 of Newton�s Dakota group, the supposed equivalent of the Atlan-tosaurus beds of Marsh. Whether these beds should be regarded asnbsp;Jurassic or as transition beds between the Jurassic and Cretaceous, ornbsp;should be made the lowest division of the Lower Cretaceous is open tonbsp;discussion. The marked uiicomformity between the Lower Cretaceousnbsp;and these later Jurassic beds, the great change in the character of thenbsp;sediments in passing from the Jurassic (No, 5) to the Cretaceous (No. 4),nbsp;and the resemblance of the few fossil shells found in No. 5 to Jurassicnbsp;forms, have led the writer to place this formation in the Jurassic. Therenbsp;is little doubt that division No. 5 of the Hay Creek section is the same asnbsp;the beds included between the Jurassic and the Dakota group at Piedmont, South Dakota, on the eastern border of the Black Hills, whichnbsp;were identified by Marsh as the representative of the Atlantosaurusnbsp;beds of Wyoming and Colorado. The Piedmont locality was visited bynbsp;J. B. Hatcher, who there found numerous large elongated vertebraenbsp;described by Marsh as a species of Barosaurus.' Similar vertebrre werenbsp;found by my assistants in the upper beds of division No. 5, in the Hay

Creek region. Professor Marsh gives the following general section of the geological horizon of vertebrate fossils in �lorth America:'

Eeferring to the �remains of an enormous dinosanrian�quot; found near Morrison, Colorado, in 1877, and described as Atlantosaurus montanusjnbsp;Professor Marsh ivrites:

When first found these fossils were supposed to be from the Dakota group, but their Upper Jurassic ago was soon after determined by the writer from evidence thatnbsp;placed the horizon beyond dispute.

Another localit3^ of Sauropoda, more recently explored by the writer, is in South Dakota on the eastern slope of the Black Hills. This is the most northern limit nownbsp;known of the Atlantosaurus beds, w'hich form a distinct horizon along the easternnbsp;flanks of the Rocky Mountains, marked at many points by the bones of giganticnbsp;dinosaurs, for neai'b' 500 miles. The strata are mainlj' shales or sandstones of freshnbsp;water or estuarj� origin. They usuallj' rest uncomformably upon the red Triassicnbsp;series and have above them the characteristic Dakota sandstones. On the westernnbsp;slope of the Rocky Mountains the Atlantosaurus beds arc also well developed, especially in Wyoming, but here they have immediately below them a series of marinenbsp;strata which the writer has named the Baptanodon beds, fr om the largest reptilenbsp;found in them. This horizon, also of Jurassic age, is shown in the section.^

From the above it is evident that Professor Marsh regarded the Atlantosaurus beds as later Jurassic.

The marine beds of the Fort Benton form a marked boundary to the Dakota group readily identified by the eye as far as the colors of thenbsp;difierent formations and the peculiar topography which each im^iressesnbsp;upon the field of view can be distinguished.

Upon examining the Dakota group of Newton in detail the Dakota sandstone is readily differentiated stratigraphically from the lowernbsp;divisions by the abrupt change in the character of the sediments, thenbsp;Dakota sandstone forming a prominent cliff, while the clays of thenbsp;Lower Cretaceous immediately underlying it yield to erosion and arenbsp;covered beneath a long grassy slope. Even more marked is the greatnbsp;change in the flora between the Lower Cretaceous and the Dakotanbsp;sandstone, but this I need not go into further.

In the Black Hills the strata of the Lower Cretaceous are thus intercalated in a series of well-determined formations, so that the exact relative position is accurately known, both stratigraphically andnbsp;paleontologically.

Fossil wood occurs in the later Jurassic of Hay Creek, and it is not improbable that fossil plants will be found in the brackish and fresh

1 Sixteenth Ann. Rep. TJ. S. Geol. Svwv., Part I, p. 145. nbsp;nbsp;nbsp;2 mia., p. 164. sihid., p. 165.

water deposited beds of the Jurassic when tbe great extent of territory covered by rocks of this age, stretching along the eastern slope of thenbsp;Kocky Mountains, is carefully explored and particular search made.

6'. Resemblance of the flora of the Hay Creek coal field to that of the Lower Potomac.�Professor Fontaine remarks:

The fact that the Hay Creek flora shows a much greater resemhlance to that of the Lower Potomac than to the Kootanie floras of British America and of Great Falls,nbsp;Montana, which occur much nearer to the Hay Creek region than does the Potomac,nbsp;of Virginia, is another surprising feature (see infra, p. 702).

In my letter of May 26, 1896, I commented on the insular position of the Black Hills, and stated that from my own observations the modernnbsp;flora is more nearly related to that of the Eastern States than it is tonbsp;the flora of the Eocky Mountains.

The Black Hills may have been covered by the ocean as late as the close of the deposition of the marine Jurassic. �fo positive evidencenbsp;has been obtained that any portion of the Hills was above water jiriornbsp;to that date, although the water continued shoaling from the Carboniferous to the later Jurassic. Neither has fossil wood been foundnbsp;in the Triassic or the marine Jurassic, and it is not until the laternbsp;Jurassic is reached that it occurs.

Jurassic formations occur west of the Black Hills and along the foothills of the Big Horn Mountains, and extend north into Montana and south through Wyoming and Colorado to New Mexico. The easternnbsp;shore of the sea depositing the marine Jurassic is not known; neithernbsp;is it known how far to the east the fresh and brackish waters extendednbsp;in the later Jurassic. The tJpjier Ci�etaceous stretches eastward intonbsp;Kansas and Iowa. Strata of Jurassic age have not been discoverednbsp;east of the Black Hills. I found the marine Cretaceous in Arkansas,nbsp;abutting on the Paleozoic, and searched the contact for the missingnbsp;formations.

In Cretaceous time a great promontory of land, formed by the union of the Ozark and Ouachita uplifts, stretched from .Missouri andnbsp;Arkansas southwesterly across Indian Territory to the Pan Handle ofnbsp;Texas. This promontory had its origin in the elevation of the Allegheny continent at the close of the Carboniferous. The laud nearestnbsp;to the Black Hills on the east during the Upper Cretaceous was thenbsp;northwestern shore of this upheaval, which crossed central Kansas innbsp;a line running northeastward into Iowa. In Jurassic and Lowernbsp;Cretaceous time the wmstern border of the continent may have beennbsp;much nearer to the Black Hills than in the Upper Cretaceous. Is itnbsp;not iirobable that the flora of the Hay Creek region may have beennbsp;derived from the east? Further, occasional strong winds in the Blacknbsp;Hills come from the east and the heavy rain storms often occur with anbsp;southeast wind. With all this, with the origin of these winds in thenbsp;Gulf of Mexico, with the great extension of the Gulf of Mexico tonbsp;southern Illinois in the Mesozoic, may not easterly winds have beennbsp;more prevalent and assisted in the migration of the plants westward?

The Cretaceous shore line lies 400 to 450 miles southeasterly from the Black Hills. The Kootanie country is situated on the head watersnbsp;of the Columbia, distant 750 miles northw(ist from the Hay Creeknbsp;coal field. Great Falls, Montana, is somewhat nearer, on the headnbsp;waters of the Missouri.

Since writing the above I have found that this subject has been gone into extensively by C. A. White, J. S. Diller, and T. W. Stanton, andnbsp;that Dana embodied' their views in a map of I7orth America in thenbsp;Cretaceous period. According to this map, the Kootanie region wouldnbsp;lie on the northeastern shore of the �Pacific border� and naturallynbsp;would belong to a different floral province. The tiny dot on the mapnbsp;representing the Black Hills, in the middle of the Cretaceous area,nbsp;seems possibly to have derived its flora from the Alleghany continent.nbsp;At the present day not only the plants, but many of the animals andnbsp;birds, are of eastern species.

7. Absence of certain forms of life in the Cretaceous formation of the Hay Creeh coal field.�Many forms of life which naturally would benbsp;expected to occur preserved in the sedimentary strata, appear to benbsp;absent. This is the more remarkable because the conditions of climatenbsp;and of deposition and the known occurrence of a most varied faunanbsp;and flora in other parts of the country during Cretaceous time wouldnbsp;seem to have been favorable not only to abundant life, but also to itsnbsp;preservation in the fossil state. It is true that such evidence is of anbsp;negative character, and that the collections made even in the richestnbsp;plant localities are scanty, yet it is not without value in throwing somenbsp;light on the conditions which subsisted in this region during the deposition of the Hay Creek beds.

a. nbsp;nbsp;nbsp;Absence of cycads.�Careful search was made, without success, fornbsp;silicifled trunks or cycads, such as are found abundantly near Minne-kahta station in the southern part of the Black Hills. Photographsnbsp;of these cycads were shown to a number of cattlemen and settlers, butnbsp;no one could recall ever having seen anything resembling them. Thenbsp;abundance of silicifled wood shows that the conditions Avere faAmrablenbsp;for their preservation.

b. nbsp;nbsp;nbsp;Scarcity of dicotyledons in the collections made.�The collectionsnbsp;were forwarded to Washington by mail, for which reason selectednbsp;material only was preserved, but in making the selection all the material left on the ground was carefully examined for impressions of leavesnbsp;of anything resembling dicotyledons. Only two or three were found,nbsp;all in the beds of division Ko. 2. In division Ko. 1, Dakota sandstone, dicotyledons occur in favorable localities, but are mostly poorlynbsp;preserved and difficult to identify.

c. nbsp;nbsp;nbsp;Absence of marine beds in the Bahota group of Afeicton.�Tha calcareous clays of division No. 5, later Jurassic, appear to have beennbsp;deposited in brackish waters. A small ammonite, a fragment of anbsp;shell resembling Unio, and a few other small and poorly preserved

shells were found in layers of impure argillaceous limestone. These fossils bear resemblance to Jurassic forms. All the beds of the Lowernbsp;Cretaceous and of the Dakota sandstones have been formed in freshnbsp;water.

d. Prevailing absence in the strata of the Lower Cretaceous and in the Pahota sandstone of all forms of life commonly occurring in bodies of freshnbsp;water.�Fossil bones of many species of the Atlantosaurus, as well asnbsp;turtles, tortoises, birds, and small mammals are described by Marsh fromnbsp;the Atlantosaurus beds of Colorado, Wyoming, and the eastern slopenbsp;of the Black Hills. Elongated vertebrae, similar to the forms figurednbsp;by Marsh, were found in the beds of division No. 5 in the Hay Creeknbsp;region, the supposed equivalent of the Atlantosaurus beds of Marsh.

From the base of division No. 4 to the top of No. 1, the Dakota sandstone, although many exposures were carefully examined and an area of nearly 120 square miles gone over, yet not even a fragment of a fossilnbsp;bone was anywhere found, not a single specimen of a fresh water ornbsp;land shell; neither are there in the beds any visible comminuted fragments of shells. Insects also seem to be wanting. What can be thenbsp;reason that while the beds in divisions No. 1, No. 2, and No. 3 werenbsp;formed in a body of fresh water, supposed to have stretched for hundredsnbsp;of miles, fishes, turtles, reptiles, and aquatic birds have left no trace ofnbsp;their presence? Neither can I recall finding any fossil plants of speciesnbsp;which would be aquatic in growth.

Fossil wood, which is very abundant in the upper beds of division No. 2, and occurs more sparingly in divisions No. 3 and No. 4, is nowherenbsp;found to have been attacked by boring mollusks. This is merely annbsp;evidence of the absence of the sea or of brackish water, all mollusksnbsp;which attack wood being marine; but 1 have thought it best to recordnbsp;the fact.

Whatever may have been the character of the vast body of fresh water in which these beds were deposited, it is reasonably certain thatnbsp;it must have had an outlet, and during the time that the beds of divisions No. 4, No. 3, No. 2, and No. 1 were forming, it could never havenbsp;been saline to such a degree that chemical precipitates would occur,nbsp;such as are characteristic of salt lakes�lakes without outlet. All thenbsp;beds of these divisions are either clays or sands. Chemically precipitated beds, as limestones, calcareous sediments, gypsum, and marlsnbsp;carrying peroxide of iron, are absent. With the exception of concretions of limonite, which occur quite abundantly in the Dakota sandstone, much of which is probably of recent formation from atmosphericnbsp;waters, all the iron in these beds is in the form of peroxide.

Briefly reviewing the evidence, it may be remarked that the coal of division No. 4 and its accompanying shales were deposited in localnbsp;marshes, occupying depressions eroded in the Jurassic surface. Thenbsp;coal was evidently formed where the vegetation grew. The bedsnbsp;resemble the coal formations of the Carbouiferous in having uuderclay

and overclay, tlie latter carrying impressions of fossil plants, and also in the character of the coal itself�dry, black, noncoking, with littlenbsp;ash or sulphur.

The third division ox)ened with alternating conditions, forming thin coals interbedded with shales and soft sandstones, but closed with anbsp;considerable sinking of the region and the dexmsition of a persistentnbsp;sandstone covering the whole Hay Creek region and dixiping northerlynbsp;and easterly until concealed beneath the marine beds of the �pijernbsp;Cretaceous.

Division IS'o. 2 opens with the formation of a heavy sandstone, continuous over a great area. The lower stratum of this sandstone is in many localities a conglomerate or breccia, and there are evidences thatnbsp;the underlying No. 3 sandstone suffered some denudation before thenbsp;deposition of the No. 2 sandstone.

These sandstones show evidences, in ripple marks, in cross bedded structure, in layers of coarse sand, and in a few beds of conglomerate, that they were deposited in shallow water by currents havingnbsp;frequent changes of direction. Division No. 2 closes with beds of claynbsp;and sandy shale, and locally thin, irregular seams of impure coal,nbsp;dex)osited in quieter waters and during alternating changes of level.nbsp;The evidence is seldom seen of denudation having taken ijlace on thenbsp;surface of division No. 2 before or accompanying the dexwsitiou of thenbsp;Dakota sandstone, because the contact of the two divisions is in mostnbsp;places concealed.

The Dakota sandstone shows more than any other sandstone the effect of currents of water iii its formation. The sediment varies widelynbsp;in character in short distances and in different beds. Broad sheets ofnbsp;heavy ripple marks occur, cross-bedded structure is strongly marked,nbsp;and iron in the form of limonite is abundant in certain layers. In short,nbsp;from an examination of the beds there is no evidence that the conditionsnbsp;which existed in the Hay Creek region during the Lower Cretaceousnbsp;were either unfavorable to the existence of life or to the preservation ofnbsp;the life record in the rocks. The land was entirely above water atnbsp;certain epochs, with marshes, swamps, and shallow isolated lakes innbsp;the dexnessions between the hills. These conditions were permaueutnbsp;long enough, during the deposition of the beds of division No. 4, tonbsp;form in the deejier basins solid coal 3 to 5 feet in thickness, free fromnbsp;partings of shale.

Later, in early Cretaceous time, there were intervals of quiet waters depositing fine sediments�clays, sandy shales, and fine sandstones.nbsp;To these mud flats succeeded widespread dejmsits of sand, laid by swiftnbsp;currents, and rixjple-marked by the waves. High winds occurred,nbsp;which tore branches from trees and leaves from ferns and bore them tonbsp;shallow sand flats, where they were buried and xneserved. It was thenbsp;age of reptiles and reptilian birds, yet not a bone or tooth marks theirnbsp;presence.

Bed 12 forms the base of the Dakota saudstoue. All the rest of the section is iiicladed in division No. 2.

The section is important from the large collection of plants obtained from bed No. 1 near the roadside along the bank of Pine Greek. Thisnbsp;horizon is 106 feet below the base of the Dakota sandstone.

About one-half mile southwest, on the opposite side of the ravine traversed by Pine Greek, the same beds appear at the top of a sandstone cliff, where the following section was measured:

Unexposed slope witli Dakota sandstone at top not measured. nbsp;nbsp;nbsp;Feet.

The conglomerate bed 1 resembles the stratum marking the unconformity of divisions Nos. 2 and 3 in the sections measured at the Barrett and the Larrabee and Young coal mines. Uniting these sections, thenbsp;thickness of division No. 2 is 149 feet. Bed 5 of this section is the samenbsp;as the plant-bearing bed 1 of the section half a mile below the northnbsp;side of the creek. From this bed 5 and from the underlying sandstone a number of fossil plants were collected.

These localities on Pine Greek are rich in well-preserved plants, are accessible, and can easily be found from the data here given.

The following is a section of Gretaceous strata at liollins tunnel, about miles southeast of Robbins Bauch, Grook Gounty, Wyoming.

Bed 9 forms the basal stratum of the Dakota sandstone covering the top of the plateau. All the other beds are in division Ifo, 2. Thenbsp;plant horizon, bed 2, is 107 feet below the base of the Dakota sandstone and is stratigraphically the same as the bed of black shales atnbsp;Bobbins Bauch, Oak Creek, and at the localities 2 to 2J miles west ofnbsp;Mrs. Dorset�s ranch on Pine Creek. This plant locality is in a shortnbsp;tunnel opened at the bottom of a narrow dry ravine in the plateaunbsp;extending easterly from Oak Creek to the State line.

Below is given a section of the Cretaceous strata exposed on the top of the plateau and in the bluffs along Oak Creek, near Bobbins Banch,nbsp;Crook County, Wyoming.

II. nbsp;nbsp;nbsp;Soft massive sandstone, weathering thin bedded, forming top of bluff on

Bed 17, tlie Fort Beuton shale, rests uiiconformably on the denuded surface of the Dakota sandstone.

The whole formation dips northeasterly toward the Belle Fourche River, where the Fort Benton has a thickness of at least 300 feet.

The Dakota sandstone, here 78 feet in thickness, includes beds 13, 14, 15, and 16.

Bed 15 is locally a loosely coherent mass of vegetable remains, mostly leaves, too much decomposed to be determinable.

Bed 5 yielded the collection of plants described by Professor Fontaine from the locality � Cliff on Oak Creek, near Bobbins Ranch,� 6 milesnbsp;northeast of Barrett post-office.

Below is a section of Cretaceous strata exposed on the north side of the valley of the South Fork of Hay Creek, at the Barrett Coal Minesnbsp;1 mile west of Barrett post-office.

10. Breccia of angular fragments of sandstone and shale in white clay, thickness varying..........................................................10 to 3

7. Drab clay shales, with plant remains.....................................2 to 5

The base of the above section is probably 30 feet above the top of the later Jurassic, which outcrops on the opposite side of the valley. Bedsnbsp;1, 2, 3, and 4, a thickness of 34 feet, lie in division hlo. 4.

The bed of thin coal, 5, the plant-bearing shales, 0 and 7, and the cliff-forming sandstone, 8 and 9, form division Ro. 3, 58 feet in thickness.

Sandstones 12 and 13 unite to form the persistent sandstone stratum of division �7o. 2, which outcrops as a cliff' along the hillsides in manynbsp;localities in the area drained by the branches of Hay Creek.

In division No. 2 are the beds 10 to 18, both inclusive, affcreffatinff 124 feet.nbsp;nbsp;nbsp;nbsp;� se ^ g

Bed 19, a low clilF near the crest of the hill, is the basal stratum of the Dakota sandstone. It forms a prominent landmark on the hilltopsnbsp;along- the north and south sides of the valley of the South Forknbsp;In this section, estimating the thickness of the beds interveningnbsp;between the lowest coal and the later Jurassic, the total exposure ofnbsp;Lower Cretaceous (No. 2, No. 3, and No. 4 divisions) is 246 feetnbsp;As the section is followed westward beds C and 7 vary greatly innbsp;thickness, increasing locally to 30 feet, and Anally thinning out to anbsp;stratum only 2 or 3 feet thick, resting unconformably on the Jurassicnbsp;These beds form a persistent plant horizon throughout the Hay Creeknbsp;region. From this locality a small collection was made of fossil plantsnbsp;In the shales over the lower coal fossil wood occurs quite abundantly'nbsp;The following is a section of Cretaceous strata exposed on the quot;northnbsp;side of the valley of the South Fork of Hay Creek at the coal mines ofnbsp;Larrabee and Young, li miles west of Barrett post-office:

' nbsp;nbsp;nbsp;,nbsp;nbsp;nbsp;nbsp;Section at cOal mines on South Fork of Hay Creek, near Barrett.

16. Unexposed, probably clays and shales, forming a grass-covered slope nbsp;nbsp;nbsp;30

2. nbsp;nbsp;nbsp;Conglomerate ofpebbles and sand, with bowldersnbsp;nbsp;nbsp;nbsp;1nbsp;nbsp;nbsp;nbsp;inch toViiiches diameter ^

In the abov^e section the Dakota sandstone, division No. 1, is represented by 17, 18, 19, and 20, aggregating 58 feet in thickness.

In division No. 2 lie beds 6 to 16, inclusive, with a total thickness of 143 feet.

The breccia (bed 6 of section) marks the unconformity with the underlying strata. In this locality beds 7, 8, 9, 10, and 11 of division No. 2 can be seen to unite in outcrop and form a continuous cliff along thenbsp;hillsides to the east and also to the west of the section measured.

In the same manner beds 4 and 5 of division No. 3 unite to form a cliff. One mile west all these sandstones unite from the cutting out ofnbsp;the intervening shale beds and form a single cliff 60 to 70 feet in height,nbsp;which continues westerly for 2 miles along the hills bordering the northnbsp;side of the valley of the South Fork.

Beds 1 to 5, inclusive, and part of the shales in the shaft should be included in division No. 3, but the line of demarcation from the underlying coal and shales of division No. 4 is covered, so that these twonbsp;horizons can not be here separated.

On the south side of the valley, at a distance of half a mile, the later Jurassic clays outcrop in a range of low hills at such relative elevationnbsp;with the coal that it is not probable that more than 25 feet of bedsnbsp;intervene between the bottom of the Larrabee shaft and the top of thenbsp;Jurassic. This gives the total thickness of the Lower Cretaceous atnbsp;this exposure 302 feet.

Plant remains occur very perfectly preserved in the shales over the lowest coal in the Larrabee shaft. Only a few specimens could benbsp;obtained at the time of the examination, owing to the bad air fillingnbsp;the shaft.

The following is a section of Lower Cretaceous strata at John Barr�s tunnel, abont 4J miles east-northeast from Barrett post-office, Crooknbsp;County, Wyoming:

6. Coal, imjinre and shaly...................................................f to |-

In the above section beds 8 and 9 belong to division No. 2, and the underlying beds are in division No. 3.

The plant horizon, bed 5, lies approximately 150 to 175 feet below the base of the Dakota sandstone, and is the equivalent of the beds carry-

ing plants at tlie Webster ranch and in shales under third sandstone at Barrett coal mines and other localities given in the third division.

This tunnel, about 60 feet long, is run on the north side of a narrow ravine, miles north-northeast from Forks post-office. Half a milenbsp;above this tunnel there are two shafts sunk in the bed of the ravine by-Williams Brothers. The following section is given by Mr. Williams ofnbsp;the beds passed through in sinking the lower shaft:

Top of shaft at base of Sandstone Cliff, bed 7 of last section. nbsp;nbsp;nbsp;Fe.ut.

Bed 1 is later Jurassic, verified by inspection of the last material excavated in the bottom of the shaft and left on the dump.

Bed ISTo. 3 and some of the associated beds may belong to division No. 4, though that formation appears to be wanting in this easternnbsp;section of the Hay Creek coal field. Nearly all, if not all, the beds in thenbsp;shaft above the Jurassic clays are in division No. 3.

Below is given a section of Lower Cretaceous and Jurassic strata ex^iosed near Webster�s ranch, 4 miles southeast of Barrett post-office:

3. nbsp;nbsp;nbsp;The prominent sandstones of divisions Nos. 2 and 3 form cliffs one-fourth and one-half mile north of this point.

The horizou of this plant bed 7 can not be accurately determined, but is not more than 200 feet below the base of the Dakota sandstone.

Division No. 4 is wanting in this part of the Hay Creek area, and the beds of division No. 3 rest unconformably on the later Jurassic.

Beds 2 and 3 of this section are later Jurassic (division No. 5) and rest unconformably on the denuded surface of the marine Jurassicnbsp;bed 1.

The plants collected at this locality were obtained from shales at the entrance to a tunnel run on the black coaly shales in search of a workable seam of coal. This tunnel is caved, so that it can not be entered.nbsp;It is reported to have been 50 or 60 feet long, and that specimens ofnbsp;well-preserved plants were obtained by the miners working there.

This plant horizon is stratigraphically equivalent to that of the localities at the cliif on the north side of the valley of the south forknbsp;of Hay Creek, the shales under third sandstone of section near Barrett, and the beds at John Barr�s tunnel, from all of which small collections of plants were made.

The following is a section of Cretaceous and Jurassic strata exposed on the hill near Lon Cottle�s ranch, 1 mile southwest of Barrett post-office, Crook County, Wyoming:

In this section beds 31 and 32 represent division ISTo. 1, the Dakota sandstone.

Beds 25 to 30, inclusive, aggregating 105 feet, form division No. 2, which is at this locality, from the union of the two massive sandstones,nbsp;beds 24 and 25, into a single cliff, not separable from division No. 3.

Division No. 3 embraces beds 19, 20, 21, 22, and 23, and the cliff sandstone 24; in all, 52 feet of strata. Bed 21 is the persistent plantnbsp;horizon of this division.

In division No. 4 are beds 4 to 18, inclusive, a total thickness of 78 feet; bed 4 resting on the eroded surface of the later Jurassic.

Beds 1, 2, and 3, aggregating 57 feet, are later Jurassic, and cover nearly the whole thickness of that formation; the marine Jurassic outcropping near the bed of the creek a short distance west of this section.

Adding 40 feet for the upper beds of the Dakota sandstone, removed by erosion, the thickness of the Dakota group of Newton, which in-eluded division No. 5 of the later Jurassic, is 387 feet.

At this locality the strata exposed of divisions Nos. 2, 3, and 4, representing the Lower Cretaceous, aggregate 230 feet.

The Black Hills, in common with the whole Eocky Mountain region, were deeply submerged beneath the ocean in the early Carboniferous,nbsp;the water shoaling near the close of the period. Thick limestones werenbsp;first deposited, succeeded by alternating beds of brilliantly colorednbsp;sandstones, with no apparent break in the regular deposition of thenbsp;sediments until the purple limestone of the Triassic, lying at the basenbsp;of the Eed Beds in the divisions of Newton, is reached.

There are strong evidences that the Carboniferous strata extended in an unbroken sheet over the entire area of the Black Hills uplift.nbsp;Cliffs of Carboniferous limestone completely encircle and inclose the

�The Archean, Cambrian, and Silurian are set forth in Newton�s report and briefly in my late �Report on the geology and ore formation of the Black Hills in the Union Hill mine investigation� innbsp;the Black Hills Mining Review for March 21,1898, pp. 6-17.

central metamorphic area, and attain an elevation far above tbe surface of the slates and schists. The great limestone divide in the northernnbsp;central hills, though its surface has lost several hundred feet of Carboniferous strata by erosion, has an elevation equal to that of Harneysnbsp;Peak, the highest isoint of granite in the Archean area. The conclusion is inevitable that these Carboniferous beds were at one time continuous over the central part of the hills and have been removed bynbsp;erosion. The beds deposited later, provisionally included in the Carboniferous, are sandstones and marls, more or less colored by peroxidenbsp;of iron, in every shade of color�yellowish-white, orange, light tonbsp;dark red.

It is as yet undetermined whether any portion of the Black Hills was dry land during the Triassic. The writer found near the head branchesnbsp;of Sundance Creek, in the Bear Lodge Eange, evidences of faulting andnbsp;unconformity between the Purple limestone and the later sedimentarynbsp;formations, the Lower Cretaceous abutting on upturned Purple limestone.

The characters of the marls. Purple limestone, gypsum, and other sediments of the Bed Beds indicate a deposition, mainly from thenbsp;action of chemical forces, taking place in a shallow sea, probably cutnbsp;off from direct communication with the ocean and subjected to recurrent periods of desiccation, all the beds apparently barren of life. Thenbsp;marls are colored by peroxide of iron, evidence of the absence ofnbsp;organic matter in the beds. Some evidences of unconformity, muchnbsp;obscured by the soft nature of the beds, were seen in the exposuresnbsp;where marine Jurassic rests on the Red Beds.

The Jurassic opened with a shallow mediterranean sea teeming with life. The small size of the mollusks and other forms preserved in thenbsp;beds of the marine Jurassic is thought to be evidence that the waternbsp;was brackish. The reddish and purple shades of color in some of thenbsp;beds of fine sediment indicate that the material of which they werenbsp;composed may have been derived from the erosion of the Red Beds innbsp;adjacent more elevated sections of the Hills. Fossil wood has not beennbsp;found to this date in the marine Jurassic, though it is abundant in thenbsp;clays of the later Jurassic, so that positive evidence is wanting of thenbsp;occurrence of areas of dry land in this epoch. The increase in thicknessnbsp;of the Red Beds and marine Jurassic in the valley of Red Water, separating the Bear Lodge from the main range of the Beach Hills, is annbsp;indication of the imoximity of land furnishing the material from whichnbsp;the sediments were derived. The Bear Lodge and the Black Hills arenbsp;distinct upheavals, and may have been in places above water at a muchnbsp;earlier period than has been heretofore thought probable.

An interval of time occurred between the elevation of the region which raised above water the marine Jurassic beds in the marginalnbsp;belt of the Black Hills and the deposition of the later Jurassic (hTo. 5).nbsp;The elevation was locally irregular; the Jurassic and underlying Bednbsp;Beds were bent upward into ridges and gentle folds, still traceable innbsp;the topography of the region, and the whole surface was later subjectednbsp;to erosion which wore the soft strata into hills and valleys. In thenbsp;depressions in this eroded surface the soft clays aud marls of the laternbsp;Jurassic were laid down.

Along the crests of the Jurassic ridges in the Hay Creek coal field the later Jurassic is absent. All the evidence derived from the occurrence of the beds of division �lo. 5 tends to show that these low elevations were dry land i n that subepoch. The old eroded Jurassic surfacenbsp;is in places well exposed to investigation in the Hay Creek field, notwithstanding the great relative modifications in the elevation audnbsp;topography of the Black Hills due to the continental elevation of thenbsp;whole Kocky Mountain region at the close of the Cretaceous and tonbsp;the great volcanic disturbances which occurred in the northern part ofnbsp;the Hills aud the Bear Lodge Range during the Tertiary.' The sediments of the later Jurassic were evidently formed from the denudationnbsp;of the marine Jurassic beds iu the vicinity. Fossil wood is quite abundant in the clays and sauds of the later Jurassic (No. 5). Saurian bones,nbsp;more or less waterwornand decomposed, occur locally in the upper beds.

An elevation of the region occurred at the close of the Jurassic or at the opening of the Cretaceous, shutting off the area surrounding thenbsp;Black Hills from communication with the ocean. It is not improbablenbsp;that this elevation of the land was continental iu its extent aud involvednbsp;the great basin lying between the Rocky Mountains aud the westernnbsp;shore of the Allegheny continent, stretching from the Pan Handle ofnbsp;Texas across Indian Territory, Kansas, Nebraska, and Iowa. Somenbsp;erosion of tlie Jurassic surface occurred before the coal formation,nbsp;division Ko. 4 of the Lower Cretaceous, was laid down in local swamps,nbsp;basins, aud irregular channels lying between the low hills aud ridgesnbsp;of the post-Jurassic tojiography.

This unconformity of the Cretaceous aud Jirrassic is strongly marked in many jjlaces iu the marginal belt and was first noted by Dr. Franklinnbsp;R. Carpenter.^

During Lower Cretaceous time many oscillations of level occurred; the relations of dry land, swamps, aud open bodies of shallow fresh

* nbsp;nbsp;nbsp;Vide published report on the Geology aud Ore Formation of the Black Hills, referred to above, p. 587.

* nbsp;nbsp;nbsp;Preliminary Report of the Dakota School of Mines upon the Geology. Mineral Resources, audnbsp;Mills of the Black Hills of Dakota, Rapid City, 1888, p. 46.

water appear never to have been constant. Only in the deposition of the coal in division No. 4 is there evidence of a period of comparativenbsp;quiet sufficiently long to admit of the formation of workable beds ofnbsp;coal in the Hay Creek field. With respect to relative areas, the bedsnbsp;of division No. 4 cover or underlie the smallest area. Division No. 5nbsp;covers nearly all the marine Jurassic on which it rests. The massivenbsp;sandstones of divisions Nos. 3, 2, and 1 ap])ear to have extended overnbsp;the whole Hay Greek region and to have reached nearly, if not entirely,nbsp;over the Bear Lodge Bange. In places on Hay Creek evidences werenbsp;observed of unconformity between division No. 2 and division No. 3,nbsp;a break in the uniform deposition of the beds corresponding to thenbsp;marked change in the flora. Less plainly marked, owing to the softnbsp;nature of the beds, is the unconformity between the clays of No. 2 audnbsp;the Dakota sandstone No. 1.

Between all the divisions some change of level occurred, some elevation or depression of the land, some advance or retreat of the water, with more or less denudation of the surface, before the later beds werenbsp;laid down. Yet no profound disturbance of the strata or upturning ofnbsp;the sedimentary beds occurred. The oscillations of level were quiet andnbsp;the successive deposits of clays, sands, and intercalated coals appearnbsp;to be nearly conformable in position. Only by examination of extendednbsp;exposures of the strata are the evidences of unconformity seen.

The unconformity between the marine Jurassic and division No. 5, or the later Jurassic, is well defined. The greatest unconformity existsnbsp;between the Jurassic and the Lower Cretaceous. In all the exposuresnbsp;examined in the Hay Creek region division No. 4 always rests on No. 5nbsp;or the later Jurassic, but in many places the beds of division No. 4 arenbsp;absent and division No. 3 rests directly upon No. 5. Along the crestsnbsp;of the ridges of the Post-Jurassic topography the eroded surface of thenbsp;marine Jurassic is overlain directly by the shales and massive sandstone of division No. 3. No positive evidence was seen of unconformitynbsp;between divisions No. 4 and No. 3 in exposures where the contact couldnbsp;be examined.

It should be noted that No. 4 was deposited in local basins of limited extent, covering only a relatively small part of the Hay Creek region,nbsp;while No. 3 stretches broadly across the field, overlying the post-Jurassicnbsp;ridges and reaching far up into the Bear Lodge Bange; that No. 4 wasnbsp;a coal-forming epoch of comparative iiuiet, but that in the deposition ofnbsp;No. 3 there was evidently a slow sinking of the land or rising of thenbsp;great body of fresh water filling the Missouri basin, the subepoch opeu-ing with quiet waters aud the deposition of clays and thin coals andnbsp;closing with the formation of the massive cliff'-formiiig sandstone (sandstone No. 3), which covers a larger area than the lowest beds of thenbsp;same division.

The following sketch of the ideal section across the Hay Creek coal field shows this reaching out of No. 3 beds onto the land, the watersnbsp;rising, and each successive bed advancing farther and farther on to thenbsp;post-Jurassic surface until all the local elevations were buried undernbsp;sandstone No. 3.

While no marked break was discovered in the uniformity of the deposition of the beds between No. 4 and No. 3, the plant horizon in division No. 3, situated in the shales immediately beneath the No. 3 sandstone,nbsp;can be distinguished in collecting from the plant-bearing beds of claynbsp;overlying the coal at the base of No. 4 by the greater abundance innbsp;tlie Hay Creek region of certain forms of plant life. In No. 3 the leavesnbsp;of Cycadacese (Zamia-like forms), commonly in a fragmentary condition,nbsp;are abundant, while in No. 4 tliere are more ferns, usually with delicatelynbsp;cut fronds, together with remains of conifers.

Unfortunately, good exposures of the plant beds in division No. 4 are rare on Hay Creek, and the collections made are very meager. Still,nbsp;the plant remains found impressed the writer with the thought thatnbsp;there was possibly a somewhat warmer climate in the region during thenbsp;deposition of No. 3 than had prevailed in the coal-forming epoch ofnbsp;No. 4.

Between division No. 3 and division No. 2 were found irregular beds of conglomerate composed of water-worn pebbles embedded in clay, andnbsp;other evidences that some erosion of the No. 3 sandstone had takennbsp;place xirior to the formation of sandstone No. 2, this unconformity marking the break in irlant life.

The ujiper beds of division No. 2 are mostly soft clays, clay shales, and sandy shales, so that evidence of unconformity between No. 2 andnbsp;the Dakota sandstone No. 1 is very difficult to obtain. Further, thenbsp;contact at the base of the cliffs of the Dakota sandstone is rarely exposed for observation. There are some evidences of a denudation ofnbsp;the No. 2 beds before the deposition of the Dakota sandstone, andnbsp;the great break in jdant life makes this more jirobable. The Dakotanbsp;sandstone covers an immense area in the Missouri basin, and from thenbsp;nature of its formation should naturally be expected to be miconform-able to the Lower Cretaceous, on which it here rests.

The unconformity of the Dakota sandstone and Fort Benton seems to be the result of erosion of the upper beds of No. 1 by the advancingnbsp;sea depositing the Port Benton clays, the profound sinking of thenbsp;region admitting the ocean into the Missouri basin.

The relation of the coal-bearing areas to the Black Hills uplift and to local subordinate uplifts aud their dependence on these will now benbsp;considered.

All the coal beds so far discovered occur in the outer border of the Black Hills, in such proximity to influences of the uplift that it isnbsp;somewhat less probable that workable coal of division No. 4 will benbsp;found beneath the later formations far out from the Hills by drillingnbsp;or shafting. The condition prerequisite for the formation of coal�thenbsp;elevation of the land above water�seems to have obtained only in closenbsp;proximity to the uplift.

In the deposition of the beds of division No. 3 the conditions were very different; there were widespread marshes forming coals, mostly ofnbsp;too limited duration to admit of workable beds being deposited; oscillations of level and frequent changes of conditions, both of life audnbsp;of the deposition of sediments, being the rule. Thin coals have beennbsp;found in No. 3 beds, in the Belle Pourche well, and in other drill holesnbsp;put down through the later formations; also in this division in the areasnbsp;of the Dakota group resting on the high ridges of the Jura surface innbsp;the Hay Creek region.

All coals occur in broad expansions of the belt covered by the Dakota group, which completely encircles the Black Hills uplift, and also innbsp;places where there are extensive areas of Lower Cretaceous beds nearlynbsp;horizontal in dip. Where the dip (which is radial from the centers ofnbsp;uplift) is steep, the belt is narrow aud no coal is found. For this reasonnbsp;the narrow outcrops of the Dakota group from Bear Buttes to Buffalonbsp;Gap, along the eastern border of the Hills, do not carry more thannbsp;thin coals. This is another instance of the influence of the uplift.

All have been formed in local basins, channels, aud depressions, and in some cases in the bottom of lakes, eroded in the Jura surface, so thatnbsp;the governing factor of the localization of the coals of division No. 4nbsp;is the irost-Jurassic topography. In this localization the depressionsnbsp;in the Jura surface have been influenced by local uplifts and elevations of the laud as well as by the folding of the Triassic aud Jurassicnbsp;beds, and also by certain faults, which in occurrence antedated thenbsp;Cretaceous.

Incident to this deposition of the strata of division No. 4 in local basins, it is noticed that where the Dakota group is thick, particularlynbsp;with the beds of divisions Nos. 3 aud 4, the coal is thick; aud wherenbsp;the formation is thin the coal beds are thin or absent. It has also beennbsp;observed that the sandstone capping the coal (the No. 4 or ocher sand-

General section of the strata occurring in the Black Bills.

Note.�On the Black Hills uplift igneous and volcanic rocks have been, iu post-Cretaceous time, iutruded through the Archean metamorphic slates and all the overlvino* a' T rhyolite, and phonolite. The rhyolites and trachytes form prominent igneous peaks�Terry Custer, Crow, and Bear Butte in this section of the Hills.nbsp;nbsp;nbsp;nbsp;^ imen ary

19 GEOL, PT 2�(2)-Face p. 593.

General section of the strata occurring in the Blade Hills.

Note. On the Black Hills uplift igneous and volcanic rocks have been, in post-Cretaceous Hme, nbsp;nbsp;nbsp;thisnbsp;nbsp;nbsp;nbsp;onbsp;nbsp;nbsp;nbsp;overlying sedimentary strata from the Cambrian to the Upper Cretaceous. These igneous rocks are in great variety, including porphyry, trachyte,

rhyolite, and phonolite. The rhyolites and trachytes form prominent igneong peaks�Terry, Custer, Crow, and Bear Butte�in this section oi the Hills. nbsp;nbsp;nbsp;�

19 GEOL, FT 2�(2)-Face p. 593.

The fossil forests, though less important, partly because so imperfectly worked up, nevertheless possess a special historical value, as has been shown, and the one species systematically described will be placednbsp;under a special head.

The remaining material, consisting of impressions of leaves, fronds, fruits, and other organs, naturally fall under two separate heads onnbsp;account of their different geological positions, those from the lower bedsnbsp;belonging to the Lower Cretaceous, while those from the upper onesnbsp;belong to the true Dakota group. With regard to the former of thesenbsp;classes, in view of the small number found iu the Minnekahta region,nbsp;most of which also occur in the Hay Creek region, it has not beennbsp;thought best to treat them separately.

In the historical and geological portions of this paper it has been necessary to discuss the occurrence of cycadean trunks iu the Blacknbsp;Hills at considerable length, and it only remaius to speak somewhatnbsp;more specially of the particular localities from which the importantnbsp;siiecimens were taken. The six specimens originally purchased of Mr.

F. nbsp;nbsp;nbsp;H. Cole were all reported to have been found on the spot to whichnbsp;Slessrs. Cole and Payne guided my party iu 1893, viz, on the southwestnbsp;side or slope of the middle ridge of Bradleys Flat. These embracenbsp;Nos. 1-6 of the collection of the United States National Museum, andnbsp;constitute the types of Gycadeoidea dacotensis (McBride) Ward emend.,

G. nbsp;nbsp;nbsp;Colei n. sp., G. pulcherrima n. sp., G. Paynei u. sp., and G. colosmlisnbsp;n. sp. No. 7, which is the type of G. minnehalitensis n. sp., was foundnbsp;by me on the same spot, as were also Nos. 8-19, mostly fragments, andnbsp;representing G. McBridei n. sp. (Nos. 8, 9,10,13,14, and 16), G. occidentalisnbsp;n. sp. (Nos. 11, 12,17, and 18), G. Marshiana ii. sp. (No. 15), and possiblynbsp;G. minnekahtensis (No. 19). The small specimen obtained from Mr.nbsp;Homer Moore in 1895 was thought by him to be from this locality,nbsp;but as it belongs to G. Jenneyana, most of the specimens of which havenbsp;been found iu the Blackhawk region, I regard this as doubtful. Thenbsp;two specimens belonging to the Woman�s College of Baltimore (Nos.nbsp;1501 and 2128 of the museum of that college), purchased by Mr.nbsp;Arthur Bibbins at the World�s Columbian Exposition at Chicago innbsp;1893, who was informed by the person who sold them to him that theynbsp;were from the Black Hills and had been cut and polished iu Germany,nbsp;belong also to G. Jenneyana, and are probably from the Blackhawk

region. The two specimens obtained by Professor Jenney from Mr. McBride were doubtless correctly represented as from the last-namednbsp;region, and also belong to 0. Jenneyana. Two other specimens whichnbsp;Professor Jenney obtained for me from Mr. Stillwell are from the samenbsp;source. One of them represents G. Jenneyana, and the other is thenbsp;type of G. Stillwelli n. sp., a species which also occurs in the Minne-kahta region. The precise locality from which the two original typenbsp;specimens of the first of these species were obtained has already beennbsp;quite fully described (supra, p. 562), and that of the only specimennbsp;known of G. excelsa n. sp. will be stated as accurately as the data permitnbsp;under the description of that species (infra, j). 638).

The much larger number of specimens (126) represented in the great Yale collection scarcely extends the range above indicated. With thenbsp;exception of No. 1 of that collection, representing G. dacotensis, andnbsp;found 2 miles west of Sturgis, as already explained (supra, p. 548),nbsp;these specimens all came from the Minnekahta and Blackhawk regions.nbsp;The careful survey, however, which I made of those two fields innbsp;October, 1898, having Mr. Wells as my guide, has greatly broadenednbsp;the earlier conceptions of them, and has not only shown that the areanbsp;over which the cycads occur in both is quite large, but also that theirnbsp;geological position is everywhere practically the same. It is the geographical and probably only to a limited extent the geological position that gives specific variety to the cycadean flora of the Black Hills.nbsp;The commoner species, such as G. dacotensis, G. McBridei, and G,nbsp;StillwelU, will probably be found at nearly all points where cycadsnbsp;occur, while the rarer ones will be restricted to special regions.

An important extension which these new discoveries has made in the Minnekahta region is the development of the large cycad-bearingnbsp;area to the southeast of Minnekahta station eastward from Parkersnbsp;Peak. Mr. Wells jioiuted out where he had obtained a large numbernbsp;of specimens in this area, but with the exceiitiou of the one that wasnbsp;so striking from being completely chalcedonized (No. 5 of the Yale collection), I was unable to identify any of the specimens from his verbalnbsp;descriptions. This will probably be done in the future, as he cannbsp;donbtless recognize most of them from the figures in this paper. Asnbsp;all three of the ridges constituting the cycad-bearing area of Bradleysnbsp;Plat are immediately adjacent to one another, this may be regarded asnbsp;a unit so far as the geographical distribution is concerned. Mr. Wellsnbsp;was able to show me the exact spot where each of the most striking ofnbsp;the large specimens occurred. Most of them were on the middle ridge,nbsp;but No. 21 of the Yale collection, the large and line specimen that constitutes the type of the new species, G. Wellsii, was found on the mostnbsp;southwesterly of the three ridges. A number of the other more striking specimens were also found there, including No. 14 of the Yale collection, doubtfully referred to G. minnekaMensis.

With regard to the Blackhawk region, it is equally clear that primarily there was one general area such as I have described, and that the specimens have not been laterally transported to any great distances.nbsp;Those found at lower levels may be regarded as having� probably beennbsp;imbedded in rocks almost vertically over where they occurred. Sotnbsp;only are the slopes to the south and southeast of the amphitheater thenbsp;result of the gradual undermining and dropping down of the higher sandstone ledges, but the amphitheater itself has its inner walls lined withnbsp;these rocks, while those on the inner side of its rim dip inward towardnbsp;its center on all sides, still further emphasizing the manner in which itnbsp;was excavated. There is therefore no special significance in the particular parts of this general area at which different specimens werenbsp;found. The two species that specially characterize this region arenbsp;C. Jenneycma and 0. ingens n. sp., and it may be said that the former ofnbsp;these species predominates at the more southern portions of the area,nbsp;while the latter occurs chiefly farther north and higher up, near the rimnbsp;of the basin. It was therefore not until Mr. Wells had explored thesenbsp;latter portions that this species was discovered, but here it was foundnbsp;quite as abundant as G. Jenneyana is below.

The general localities for all the cycads of the Yale collection are as follows:

Nos. 2-8,7. Minnekahta region (impossible at present to designate their exact location except in the few cases mentioned above), 86nbsp;specimens.

Nos. 88-126. Blackhawk region (more precise location of a few specimens given above and others under the description of the species), 39 siiecimens.

To sum up the subject of the geographical distribution of fossil cycadean trunks in the Black Hills, it may be stated that they havenbsp;thus far been chiefly found in two areas�the one on the southeast andnbsp;the other on the east side of the Hills, the latter near the center fromnbsp;north to south. The former of these areas, if we combine, as wenbsp;properly may, the Bradleys Flat and Parkers Peak localities into one,nbsp;extends in an east and west direction for at least 5 miles with a widthnbsp;varying from half a mile to 2 miles. The other, as already stated, isnbsp;from 1 to 2 miles wide east and west, by 3 to 4 miles long north andnbsp;south.

In addition to these areas, however, cycads have actually been found and collected at four other widely separated points in the Cretaceousnbsp;rim, one of which I have myself visited. This is 2 miles west of Sturgis, as above stated. Another is the place where the unique specimennbsp;representing the new species G. excelsa was found, described as fullynbsp;as the data permit under that species.

A third locality is somewhere between Bellefourche and Spearfish, not yet definitely fixed, but believed to be in the breaks of Hay Creek.

This locality is well vouched for. The specimen was obtained several years ago by Mr. Stillwell from a person residing in that part of thenbsp;country. Mr. Wells purchased it of Mr. Stillwell and owned it a number of years before disposing of it. He described it minntely to me,nbsp;and from his description I judge that it represents a new species.nbsp;He is certain of the above facts as to location and will probably learnnbsp;further particulars in the future.

The fourth and last of these outlying localities is in the vicinity of Sundance, in Wyoming. Mr. Wells showed me a specimen at hisnbsp;house that he had himself obtained from there, and he intends tonbsp;make further explorations in that region at an early day. The jmsi-tion of the cycads here is the same as at all other points, viz, in thenbsp;soft sandstones and shales near the summit of the Cretaceous rim.

Cycads have therefore actually been found on nearly all sides of the Black Hills in the same geological position, and there is no doubtnbsp;that other localities will be discovered which will close up more andnbsp;more the intervals separating the areas now known.

All the fossil cycadean trunks that have been found in America thus far probably belong to one genus, the Cycadeoidea of Buckland. In 1894nbsp;I published a revision of that genus^ and in 1897 I described the sevennbsp;species then known from Maryland.^. In the latter paper I gave a fullnbsp;description of the genus in the light of modern research. The classification adopted was not that of Engler in Engler and Prantl�snbsp;Natiirlicheu Pflanzenfamilien (II. Teil, 2. Abteilung, pp. 24-26), whichnbsp;is modeled after Schimper�s treatment in Zittel�s Handbuch der Palse-ontologie (Abth. II, pp. 211-232), and is no longer accepted, having beennbsp;materially changed by Potonie and Engler in the same work (Nachtrage zu II-IV, x)p. 14-17; 341,360). According to this the Bennettitalesnbsp;form a class distinct from the Cycadales, or living cycads, consistingnbsp;of the exclusively extinct family Bennettitace�, coordinate with thenbsp;family Oycadacete, which is restricted to the forms now living. Potonienbsp;would refer the greater part of the forms that I have called Cycadeoideanbsp;to Carruthers�s genus Bennettites, which Count Solms Laubach restrictsnbsp;to such as have been found to contain seeds in the fruits, i. e., practically to one species, B. Oihsoni, and chiefly to one specimen. I havenbsp;already pointed out^ that this is simply an accident of preservationnbsp;and not a good ground for the establishment of a new genus, and therefore I would adhere to Bucklaud�s name, which has priority over allnbsp;others, and call them all Cycadeoidea. In all other resjiects I am quite

* nbsp;nbsp;nbsp;Fossil cycadean trunks of Nortli America, with a revision of the genus Cycadeoidea Buckland:nbsp;Proc. Biol. Soc. Washington, Vol. IX, April 9, 1894, pp. 75-88.

* nbsp;nbsp;nbsp;Descriptions of the species of Cycadeoidea, or fossil cycadean trunks, thus far discovered in thenbsp;Iron Ore belt, Potomac formation of Maryland: Proc. Biol. Soc. Washington, Vol. XI, March 13,nbsp;1897, pp. 1-17.

willing to conform to^the classification of Engler and Prantl�s great work. The arrangement will therefore be as follows;

Subkiiigdom SPERMATOPHYTA (Phanerogams).

Class BENNETTITALES Engler, 1897.

1827. nbsp;nbsp;nbsp;Cyct�eoWea Bncklaiid: Proc. Geol. Soc. London, Yol. I, No. 8, pp. 80-81 (session

1828. nbsp;nbsp;nbsp;Cycadeoidea Buiskland : Trans. Geol. Soc. London, 2d Ser., Yol. II, pp. 375-401,

Pis. xlvi-xlix (volume dated 1829, but memoir probably issued separately in 1828).

Trunks chiefly low (30 to 90 cm. in height) and more or less conical or oval iu shape, but sometimes tall, reaching over a meter in height, andnbsp;cylindrical, 15 to 75 cm. in diameter, usually simple, but sometimesnbsp;branching, with a depression at the summit, in the middle of which,nbsp;when not decayed, there is a terminal bud of conical shape; terminalnbsp;bud, however, usually wanting in the fossils, leaving a cavity commonlynbsp;known as the �crow�s nest,� by which name, for this reason, the specimens from the Portland quarries are popularly known. The armornbsp;consists of appendicular and reproductive organs surrounding andnbsp;enveloping the axis, the former being the bases of the leaf stalks ornbsp;petioles, which are surrounded by a dense mat of ramentum or fine hairs.

The leaf stalks are normally four-sided and four angled, the lateral angles acute and nearly equal, the vertical angles obtuse but unequal,nbsp;the lower mueh sharper than the upper, so as to render the cross sectionnbsp;subrhombic. This form varies on the one hand to a true rhomb, and onnbsp;the other hand to a true triangle, the most frequent intermediate typenbsp;being that in which the upper angle is wanting, and the two uppernbsp;sides are reduced to a simple curve or arch, so that the cross sectionnbsp;assumes the form of a drawn bow and bowstring, the arch formed bynbsp;the two upper sides representing the bow, and the two lower sides,nbsp;with the reentrant angle, representing the bowstring. In size the leafnbsp;stalks vary from 15 to 35 mm. in width, measured between the lateralnbsp;angles, and from 5 to 20 mm. in height measured between the verticalnbsp;angles, or from the lower angle to the summit of the arch formed bynbsp;the two upper sides. The line joining the former is not generallynbsp;horizontal or at right angles with the axis of the trunk, but one isnbsp;usually slightly lower than the other. The line joining the latternbsp;is not generally vertical or parallel to the axis of the trunk, but one is

usually a little on one side of the other. The only portion of the leaf bases that is always preserved iu the fossil state is the mat of ramen-taceous hairs that surrounds them. In the great majority of cases thenbsp;petioles themselves are decayed to a greater or less distance below thenbsp;summit of these mats, which thus constitute walls surrounding andnbsp;inclosing the portion that remains of the petioles, if any, and in theirnbsp;absence forming definite cavities having the shape of the cross sectionnbsp;of the leaf stalks, which constitute the leaf scars. These leaf scars,nbsp;with or without the lower portion of the leaf bases, penetrate to thenbsp;axis of the trunk and form a varying angle with it. Normally thisnbsp;angle is a right angle over all the central portions of the trunk, whilenbsp;below the organs are slightly descending and above more and morenbsp;ascending to the apex, where they become vertical. At the summit,nbsp;too, they diminish iu size and usually in form, and are reduced in andnbsp;immediately around the terminal bud to small triangular or polygonalnbsp;bracts {perulce of Miquel). In some species (C. Uhleri) all the organsnbsp;of the body of the trunk are detlexed, and in some {C. Gouclieriana,nbsp;C. minnekahtensis) there is a definite zone near the middle of thenbsp;trunk, below whic.h they are descending and above which they arenbsp;ascending. The leaf scars are arranged in a more or less exactnbsp;quincunx order, and usually iu two sets of spiral rows around thenbsp;trunk, in one of which they ascend from the base in the directionnbsp;from left to right and in the other from right to left, crossing each othernbsp;at varying angles and both rows making a certain angle with the axisnbsp;of the trunk, which varies with the species and more or less with different specimens of the same species. One of the two sets of rows isnbsp;usually more distinct than the other, but the more distinct rows sometimes pass upward from left to right and sometimes from right to left.nbsp;The bases of the petioles when present and well preserved often shownbsp;at the surface presented to view a row of pits all around x)arallel to thenbsp;walls and at different distances from the margin representing the vascular strands. Other such pits are sometimes present near the center.nbsp;The x^etioles are frequently disarticulated at a natural joint, which maynbsp;fall near or at the summit of the scar or it may fall some distance withinnbsp;the scar. In some species there are two such joints separated by a node.nbsp;Occasionally these joints consist of a thin membranous diajibragmnbsp;stretching across the petiole, of firmer texture than the rest of its substance. Even where the petioles are wholly absent the position of thenbsp;joints or dia^diragms can sometimes be determined by a sharp ridgenbsp;around the inside of the scar. The walls are made up of the ramentumnbsp;of two adjacent i^etioles. In some cases these matted masses are sonbsp;dense as to produce a simple homogeneous plate on all four of the sides,nbsp;which, where the petioles are wan ting, forms a deep, angled cavity ofnbsp;exactly the shape of a cross section of the petiole. Usually the portion ofnbsp;the wall furnished by each of the adjacent petioles can be distinguishednbsp;by a junction line or commissure, visible along the outer edge of the wall.nbsp;This commissure sometimes takes the form of an intermediate plate of

a less dense consistency than tlie two outer plates, In other cases this central plate is much thicker than the two outer ones, which latter maynbsp;be reduced to the appearance of thin linings of the scars. In still othernbsp;cases the central portion is more or less open and cavitous. The wallsnbsp;vary from 1 mm., or even less, to 5 mm. or, in rare cases, 8 mm. innbsp;thickness.

The other class of organs that help to make up the armor are the reproductive organs. These are borne on all parts of the surface ofnbsp;the trunks, except, perhaps, in immediate connection ^rith the terminalnbsp;bud, which is exclusively an organ of growth. They are scatterednbsp;about with very little order over the surface among the leaf scars.nbsp;They are usually of a harder substance than that of the foliar organs, andnbsp;better adapted to resist the erosive influences to which the fossil trunksnbsp;are exposed. Where the trunks are worn, therefore, the reproductivenbsp;axes are liable to protrude somewhat. Viewed from without, theynbsp;usually present au organ with an elliptical cross section, the longernbsp;diameter being nearly horizontal, variable in size, but always largernbsp;than the leaf scars. The central portion is often wanting, and a funnel-shaped cavity less deej) than the leaf scars takes its place. When thenbsp;central portions are present they show markings having the form whichnbsp;the outer ends of the essential organs present, which is very variablenbsp;and usually obscure. Surrounding the central portions are severalnbsp;rows of open scars arranged concentrically. These scars are sometimesnbsp;triangular, quadrangular, polygonal, or nearly circular; but the mostnbsp;of them, especially the outer ones, are somewhat crescent-shaped, having the concave side toward the center. The inflorescence is a spadixnbsp;surrounded by an involucre, consisting of the concentrically aivangednbsp;bracts or scales whose scars were last described. The spadix has anbsp;receptacle at base, located near the inner surface of the armor and supplied with fibers from the axis. From the receptacle there rise twonbsp;kinds of organs; first, peduncles or filaments, known in a few specimensnbsp;to bear seeds, and conjectured in one specimen to bear anthers at theirnbsp;summits; and, second, elongated chaff-like scales more numerous thannbsp;the latter and rising above them, the upper portions expanding andnbsp;forming a dense mat or covering over the essential parts. In mostnbsp;cases all these organs are wholly included in the armor, the only seedsnbsp;that have thus far been found being deeply embedded in the tissues.nbsp;The organs of inflorescence are probably axillary, but owing to thenbsp;proximity of the leaf scars this is not generally apparent. In regionsnbsp;of the surface where they occur they usually crowd the leaf scars andnbsp;cause variations in their shape. This effect is most marked on thenbsp;upper sides of the scars, often quite obscuring or obliterating their normal features.

The axis of the trunk inclosed in the armor when complete consists of four parts, which, enumerated from without inward, may be denominated respectively as (1) the libro cambium, (2) the parenchymatousnbsp;wood, sometimes called the cortical parenchyma, (3) the wood proper

or flbrovascular zone, and (4) the medulla or pith. In many cases the libro cambium zone can not be definitely distinguished from the corticalnbsp;parenchyma, and nothing is visible but the large and numerous vascular bundles passing out from the interior into the leaves; but sometimes there occurs a definite line or thin zone of loose tissue immediately below the bases of the leaf stalks. There is usually a zone ofnbsp;apparently homogeneous cellular tissue, often of considerable thickness,nbsp;filling the interval between the armor and the woody axis. The woodynbsp;zone consists of one or more rings of exogenous tissue traversed bynbsp;medullary rays. Where more than one, they are separated by thinnbsp;interstices of parenc.hymatous tissue. The medulla is usually largenbsp;and composed of coarse parenchyma.

The genus Oycadeoidea is illustrated by five plates devoted to characteristic trunks from Europe and America. PI. LVII represents the two original species of Buckland, C. megalophylla and G. micropliylla,nbsp;from the Purbeck of the Isle of Portland, and also a third species, C.nbsp;portlandica, from the same beds, described by Carruthers in 1870. Allnbsp;of the specimens here figured were found by Dr. Alfred Eussel Wallacenbsp;and myself on the occasion of our visit to Portland on August 17,nbsp;1894, and the specimen represented by fig. 3 is the one collected by usnbsp;in one of the quarries.^

On PI. LVIII is reproduced the figure of Oycadeoidea Masseiana Cap. amp; Solms., which appeared in the Sixteenth Annual Report of the Survey with a full history of its discovery and significance (cf. Part I, pp.nbsp;502-510, pi. ciii). It is a fair representative of the genus from thenbsp;Italian beds.

On PI. LIX is given a reproduction from a photograph sent me by Prof. H. B. Geinitz of the great C. Beichenhachiana (G�pp.) Cap. amp;nbsp;Solms., now in the Dresden Museum. It was found at Lednice, nearnbsp;Wieliczka, in Galicia, a century and a half ago, and treated by Knorrnbsp;and Walch in their great work of 1755. It was long regarded as thenbsp;largest fossil cycad in the world (see infra, pp. 604,605).^

PI. LX represents a group of cycads from the iron ore beds of Maryland, all belonging to the genus Oycadeoidea. Several of these are embraced in the group represented on pi. c of Part I of the Sixteenthnbsp;Annual Report of the Survey, but at that date they had not beennbsp;named or described.

This was done in 1897,� but no references were then given to published figures. This may therefore be regarded as the first illustration of these species, and the group constitutes an excellent representationnbsp;of the genus Oycadeoidea. The specimens represented in this groupnbsp;were all collected or obtained by Mr. Arthur Bibbins and belong tonbsp;the Woman�s College of Baltimore.

^Por synonymy see Proceedings of the Biological Society of Washington, Yol. IX, 1894, p. 85. ^Proceedings of the Biological Society, Yol. XI, 1897, pp, 9-17.

Finally, on PI. LXI is given a group of the leading types of the species from the Black Hills, embracing the six original trunks obtained fromnbsp;Mr. Oole and the large branching trunk, G. minnekahtensis, collectednbsp;in 1893.

1893. nbsp;nbsp;nbsp;Bennettites (iaco/ensis McBride, in part: American Geologist, Vol. XII, p. 249,

pi. xi, fig. 1 (non fig. 2); Bull. Lab. Nat. Hist. State Univ. of Iowa, Vol. II,

1894. nbsp;nbsp;nbsp;Cycadeoidea dacoiensin (McBride) Ward, in part; Proc. Biol. Soc. Washington,

Trunks large (30 to 50 cm. high, 30 to 50 cm. in diameter, 100 to 150 cm. in girth), short-cylindrical, contracted below, dome-shaped above,nbsp;symmetrical, sometimes laterally compressed and elliptical in crossnbsp;section, probably subsequent to entombment, bearing a number ofnbsp;short secondary axes or undeveloped branches in the form of roundednbsp;protuberances, or, in case of decay, of corresponding saucer shapednbsp;depressions; apex imeseuting a flattened surface with a central elevation, studded with polygonal bract scars and bases arranged in rowsnbsp;which sometimes proceed in helicoid form from the center outward;nbsp;rock substance of a dark brown or reddish color, firmly silicifled, hardnbsp;and heavy, sometimes weighing over 100 kilograms, fine-grained;nbsp;organs of the armor slightly ascending except near the base, thenbsp;angle increasing toward the summit, where they become vertical; leafnbsp;scars, where not interrupted, forming two series of spiral rows whichnbsp;proceed in different directions and intersect one another, those fromnbsp;right to left nearly horizontal below and curving upward until theynbsp;form an angle of 45� with the vertical axis, the opposite series lessnbsp;distinct, forming a small angle (5� to 10�) with the axis; scars sub-rhombic and nearly uniform in shape, larger below, diminishing upward,nbsp;the distance between the lateral angles varying from 16 to 26 mm.,nbsp;and that between the vertical angles from 10 to 16 mm., empty fromnbsp;decay of the petioles, at least to considerable depth, sometimes to anbsp;depth of more than 5 cm.; interspaces between the scars very thicknbsp;though variable, sometimes 16 mm., presenting an undulate ornbsp;wrinkled surfa(!e with indications of deeper lines of separation of thenbsp;walls; spadices large and somewhat elliptical in outline, the longernbsp;axis nearly horizontal, 8 to 10 cm. long, the shorter nearly vertical andnbsp;5 to 7 cm.; involucral bract scars numerous, arranged in concentricnbsp;ellipses around the central organs in many somewhat distinct rows,nbsp;increasing in size from the center outward, subrhombic, triangular, ornbsp;polygonal in shape, 2 to 20 mm. in diameter, apparently passing insensibly into the normal leaf scars, empty like them, forming deep cavitiesnbsp;or punctations; essential organs of the buds, flowers, or fruits sometimes wanting, their place occupied by a deep circular cavity, morenbsp;frequently represented by a dark and firm substance, which in somenbsp;of the smaller ones projects beyond the general surface; armor 5 to

7 cm. thick, separated from the ligneous axis by a definite line; cortical parenchyma 5 cm. thick; fibrous zone 4 cm. thick with three or more rings of wood, or sometimes presenting a number of thin concentric laminae of alternating black and brown substance, apparentlynbsp;representing as many rings of wood, and inclosing the homogeneousnbsp;medulla 5 to 15 cm. in diameter, conforming in cross section to the trunk.

Only one of the specimens belonging to the TJ. S. National Museum is referable with certainty to this species. This is the fine trunk,nbsp;No. 1, of the collection of six purchased of Mr. Cole. That this isnbsp;specifically identical with Professor McBride�s specimen representednbsp;by fig. 1 of his plate there is no room to doubt. It is, however, difficult to reconcile it with his description in view of the fact that in thatnbsp;description he has included two specimens belonging to entirely different species, his fig. 2 showing none of the external characters of fig. 1,nbsp;or of the specimen in hand, but clearly belonging to the same specificnbsp;group as several of the fragments collected by Professor Jenney andnbsp;myself from the Minnekahta locality in 1893, as will be shown belownbsp;(pp. 613-614). As Professor McBride in his description includes characters that could scarcely have been exposed in the perfect trunk represented by his fig. 1, it seems clear that he derives such from the specimennbsp;fig. 2, which was probably a fragment showing these characters in thenbsp;fractures. It was therefore a question whether to retain the name ornbsp;not. I conclude to do so for so much of Professor McBride�s descriptionnbsp;as applies to his fig. 1.

The Museum specimen is somewhat larger than the one at the University of Iowa, standing over 44 cm. high, having a girth of 122 cm., and weighing 90.27 kilograms. It is one of the most perfect and beautiful cycadean trunks that have thus far been brought to light.

Thirteen of the specimens in the Yale collection are referred to this species. These are Nos. 1, 3, 5, 6, 13, 30, 39, 43, 54, 62, 63, 95, and 106.nbsp;Of these Nos. 3, 5, and 54 are nearly perfect trnnks, and one of these.nbsp;No. 54, is larger than the one at the U. S. National Museum.

In Pis. LXII and LXIII are given side, top, and base views of the original type specimen, No. 1, of the U. S. National Museum; in Pis.nbsp;LXIV and LXV, side and top views of the equally fine and somewhatnbsp;larger trunk. No. 54, of the Yale collection, and PI. LXVI affords anbsp;view of the inner parts from one side of the Yale specimen No. 13.

This is the most common species in the Black Hills, and has been found in the Minnekahta and Blackhawk regions, and 2 miles west of Sturgis.

Trunks colossal, subconical, more or less laterally compressed, sub-cylindrical, dark colored, hard and heavy, weighing from 100 to over

^Itwas not thought necessary to alter the proofs of this memoir by quoting the Proc. U. S. Nat. Mus., Vol. XXI, pp. 197-229, as the original place of publication of the new species of fossil cycadeannbsp;trnnks, because the manuscript was prepared in duplicate and simultaneously submitted for publication in both places. As, however, the paper in the Proc. Nat. Mus. appeared in October, 1898, thesenbsp;species, with the exception of C. Wielandi, p. 621, are not new here in the strict sense of earliestnbsp;publication.

300 kilograms, 38 to 79 cm. liigli, 40 to 66 cm. iu major, 26 to 46 cm. in minor diameter, 100 to 180 cm. in girth, bearing numerous relativelynbsp;small branches not projecting far beyond the general surface; terminalnbsp;bud low, set in a circular platform of small polygonal scars filled bynbsp;the bases of the leaves or bracts; organs of the armor and secondarynbsp;axes horizontal at the middle portion of the trunk, somewhat descending at the lower portion and ascending at the upper portion; phyllotaxynbsp;much obscured by the intrusion of other organs, but spiral rows ascending from left to right at an angle varying from 75� below to 45� abovenbsp;plainly traceable; leaf scars subrhombic to nearly rhombic, very smallnbsp;relatively to size of trunk, 13 to 16 mm. between lateral, and 8 to 12nbsp;mm. between vertical angles, empty to a depth of 13 to 50 mm., thenbsp;bottoms of the cavities apparently occupied by portions of the leafnbsp;bases; interstices between the scars very variable, but, except at thenbsp;summit, generally large, sometimes 25 mm., nearly even on the surfacenbsp;but finally marked with mostly horizontal but variously curved ornbsp;crooked ridges or wrinkles, with occasional indications of planes ofnbsp;separation into two, three, or even five plates; walls much thinnernbsp;in the upper portion, often broken down in the specimens, displaying the striate inner surface of the scars diminishing in size below;nbsp;reproductive organs abundant at all parts of the trunk, large, wellnbsp;developed, and conspicuous, after rising somewhat above the surface,nbsp;forming gentle swellings or more abrupt protuberances, elliptical innbsp;shape, the major axis nearly horizontal, 5 to 10 cm. long, the minor axisnbsp;3 to 5 cm., usually with a solid center, sometimes with a small centralnbsp;cavity surrounded by firm substance, the whole inclosed within concentric elliptical rings or rows of iuvolucral bract scars which increasenbsp;in size from the center outward, are empty and have the form of thenbsp;leaf scars, into which they occasionally seem to graduate; armor 5 tonbsp;10 cm. thick, attached to the woody axis by a uniform layer of barknbsp;6 mm. thick; cortical parenchyma 4 to 6 cm. thick; fibrovascular zonenbsp;also 4 to 6 cm., separated into two distinct rings of wood, each consisting of a loose, spongy substance inclosed in a firm plate or thin hardnbsp;layer, the outer ring 35 mm. and the inner 25 mm. in thickness, throughnbsp;all of which the medullary rays pass, forming a sort of columnar structure; medulla more or less elliptical in cross section, 11 to 13 cm. bynbsp;15 to 20 cm. in diameter, decayed, leaving a cavity at the base in onenbsp;specimen, and in another having a concentric structure consisting ofnbsp;four zones or rings of soft porous material, scarcely differing except innbsp;coloration.

The large perfect specimen, No. 6 of the Cole collection, is the largest cycadean trunk known in the world. Prior to its discovery thenbsp;great G. Beichenhachiana (G�pp.) Cap. amp; Solms. (see supra, p. 601nbsp;and PI. LIX) from Galicia, which is at the Mineralog.-Geolog. Museumnbsp;at Dresden, and which I have not seen, had taken the lead. Professor H. B. Geinitz was so kind as to send me an excellent photo-

graph of that specimen and on this I find the dimensions marked. It is 50 cm. high, 54 cm. in major and 44 cm. in minor diameter, and 157nbsp;cm. in girth. It is therefore not so tall as the American specimen bynbsp;29 cm., has a major diameter 25 cm. less, and a minor diameter 2 cm.nbsp;less, showing that it is less flattened, but the circumference is 23 cm.nbsp;less.¹

Eight of the specimens in the Tale collection belong to this species, viz, �Tos. 2, 7, 9,10,17,37,40, and 55, of which Kos. 2 and 10 are perfectnbsp;trunks, but are both much shorter in proportion to their size than thenbsp;great National Museum type. They are also less laterally compressed.nbsp;They may have been somewhat vertically compressed. No. 37, thoughnbsp;incomplete, is a fine specimen weighing nearly 150 kilograms, and hasnbsp;a height of 71 cm. No. 55, though it has lost considerable at thenbsp;summit, still weighs 110.68 kilograms. No. 40, which represents lessnbsp;than half of the original trunk, is also a line fragment. The rest arenbsp;smaller and more imperfect.

In Pis. LXVII and LXVIII are shown side and base views of the great type trunk No. 6 of the U. S. National Museum. Pis. LXIX-LXXII illustrate the species as represented in the Yale collection bynbsp;Nos. 2, 10, 17, and 55. They show considerable variation in the formnbsp;and size of the trunks.

Trunks large, ellipsoidal, subcylindrical, or somewhat barrel-shaped, more or less laterally compressed, rounded at the summit, bearing numerous small secondary axes in the form of protuberances, light reddish-brown or drab colored, fine-grained, hard and rathel heavy, sometimesnbsp;weighing nearly 100 kilograms, 40 to 55 cm. high, 30 to 45 cm. innbsp;diameter and more than 1 meter in girth j terminal bud not prominent;nbsp;organs of the armor about horizontal except near the summit; phyllo-taxy much disturbed and not traceable; leaf scars rather small, subrhom-bic or nearly rhombic, often trapeziform or very irregular in shape,nbsp;average distance between the lateral angles 20 mm. and between thenbsp;vertical ones 12 mm., none of the angles rounded, all except the smallnbsp;ones at the apex empty to considerable depth; rameutaceous interspacesnbsp;exceptionally thick, sometimes 2 cm., presenting a smooth but gently

The photograph sent me hy Professor Geinitz was taken from the specimen in position as mounted on a support in the Dresden Museum. Judging from it alone I should say that the trunk is herenbsp;inverted, but to be certain it would be necessary to examine it. It is clear that in the present positionnbsp;the leaf scars have a decided downward direction, which is rare but not unknown (e. g., C, Uhleri).nbsp;Moreover, the scars, which are subtriangular, have now their sharp angle upward, which, if thenbsp;specimen is right side up, would indicate that the keel of the petioles was on the upper side, a condition which I have met with in only two other species� C. aspera and 0. insolita, described below.nbsp;Goppert�s figure (Jubiliiums-Denkschr. d. Schlea. Ges. f. vat. Cult., 1853, pi. viii, fig. 4) shows thenbsp;specimen in the same position, i. e., probably inverted.

undulating surface, lowest in the middle part, rising to the scar which forms a sharp edge, producing the general effect of being molded innbsp;plastic clay; reproductive organs very large, abundant, and conspicuous, greatly distorting the arrangement of the leaf scars as well as theirnbsp;form, often nearly circular in cross section, 4 to 5 cm. in diameter, showing the remains of the central organs surrounded by concentric circlesnbsp;of large, empty, and deep involucral bract scars which are semilunar ornbsp;somewhat triangular in shape, and may reach 7 mm. in length; armornbsp;about 7 cm. thick, cortical parencliyma 4 cm., fibrous zone 4 cm., showingnbsp;two rings, the inner projecting at the base, concentrically laminated andnbsp;inclosing the much decayed medulla about 12 cm. in diameter.

There are two siiecimens of this species in the Yale collection, viz, ifos. 21 and 59, the former of which is a hue, nearly perfect trunk, large andnbsp;handsome, weighing 92.76 kilograms. I was at first inclined to regardnbsp;them as belonging to C. minnelcahtensis on account of the general resemblance of the external surface, but this obviously can not be done,nbsp;because these trunks are unbranched and symmetrical in form. Innbsp;this respect they approach G. dacotensis and G. colossalis, but here thenbsp;surface differs completely. Ho forms intermediate in either of thesenbsp;respects occur in either collection, and there is no escape from regardingnbsp;these two trunks as constituting a new species.

I have named the species for Mr. Henry F. Wells, who obtained these and nearly all the rest of the Yale collection, and from whom Professornbsp;Marsh purchased them. He may therefore be regarded as the collector,nbsp;which, under the approved rules for naming species, requires the usenbsp;of the genitive form.

Pis. LXXIII and LXXIV give side and base views of Ho. 21, and PI. LXXV shows the iierfect side of Xo. 59. Both specimens are fromnbsp;the Minnekahta region.

Trunks gigantic, much branched and irregular in form, the type and only perfect specimen known weighing 219.09 kilograms, 74 cm. high, 50nbsp;cm. in diameter exclusive of branches, 79 cm. across at maximum spreadnbsp;of branches, 150 cm. in girth, light brown or chestnut colored, smoothnbsp;on the outer surface, presenting the appearance of having been moldednbsp;in plastic clay, moderately heavy; branches very large, forming conicalnbsp;protuberances projecting from the middle portion of the trunk, givingnbsp;it a winged appearance, other branches proceeding from other parts,nbsp;especially below, composite, i. e., the main branches or primary axesnbsp;having lesser or secondary branches, prominent terminal buds, sometimes themselves compound, on all the branches, often very perfectnbsp;with a sort of neck; organs of the armor declined over most of thenbsp;surface, phyllotaxy obscure and not traceable; leaf scars subrhombicnbsp;to nearly rhombic, averaging 22 mm. wide by 10 mm. high, the unusual

vertical narrowness perhaps due to compression, very variable, however, in all respects, those on the lesser branches smaller, usually empty and striate within; ramentaceous interstices usually thick, 5 tonbsp;15 mm., firm and fine-grained, smooth and polished but somewhatnbsp;undulating, the edges of the scars sharp, always without signs of subdivision; reproductive organs numerous, simulating the small branches,nbsp;the central part preserved but heterogeneous, showing scars andnbsp;markings of the essential organs, varying from 12 to 50 mm. in diameter,nbsp;surrounded by small involucral bract scars; armor about 6 cm. thick,nbsp;separated from the underlying tissues by a thin porous layer; corticalnbsp;parenchyma about 5 cm. thick, fibro-vascular zone 8 cm. thick withoutnbsp;visible subdivision into rings; medulla not clearly shown, and internalnbsp;structure generally more or less conjectural.

The remarkably fine but weird and anomalous specimen upon which the above description is almost wholly based was found by our partynbsp;lying partly buried in the ground in the same place where the othernbsp;trunks had been gathered. It was overgrown with lichens in manynbsp;places, and had been regarded so uncouth as not to be worth transporting to Hot Springs. I arranged with Messrs. Payne and Cole to havenbsp;it shii^ped to Washington, and it arrived in due time in safety. It holdsnbsp;the fourth rank as to size and weight, but differs from all others in sonbsp;many respects that a comparison with any is difficult. Specifically itnbsp;approaches most closely to G. pwlcherrima^ but lacks all the symmetrynbsp;and definiteness of that form. It is only in the fact that both are verynbsp;branching, esj)ecially around the middle part of the trunk, that theynbsp;have an external resemblance.

The specimen shows a fine terminal bud at the apex of the principal trunk, and several others on the other branches. Except near the summits of the several branches, the leaf scars and other organs of thenbsp;armor are decidedly descending, but on the main branch or trunk, somenbsp;distance above all the lateral branches, there is a sharp line separatingnbsp;the descending from the ascending scars above. This feature I havenbsp;seen elsewhere only in 6'. Goucheriana from Maryland.

The only other specimen in the collection that could with any propriety be included under this specific head is the small trunk picked up at the same time and place and numbered 19. This may represent anbsp;very young state of this species with all the characters in miniature andnbsp;devoid of reproductive organs. It is branched much in the same way,nbsp;longitudinally compressed, lacks a little of the base and part of one sidenbsp;below, but for purposes of description is practically complete. Thenbsp;entire trunk was only 18 or 20 cm. high, 14 or 15 cm. in its longer andnbsp;7 or 8 cm. in its shorter diameter, with a maximum girth of 36 cm. Itsnbsp;present weight is 1.81 kilograms. The dimensions are therefore lessnbsp;than one-fourth and the weight is less than one-twelfth of the largenbsp;trunk. It might even have been wholly subterranean, as in the livingnbsp;Zamia angustifolia.

Amoug the fragiiieiits in the Yale collectiou I found eight that belong to this species, and, as the Jfational Museum type is nearly perfect, these add somewhat to our knowledge of the inner parts of thenbsp;trunk. These specimens are numbered 14, 22, 24, 32, 41, 71-72, 83, andnbsp;86. They consist chiefly of branches torn away from large trunks, andnbsp;several of them may have belonged to the same trunk. Some of themnbsp;may be found to lit together, but, as they were lying about in differentnbsp;rooms, and even on different floors, ofthe Peabody Museum, it was imiios-sible for me to correlate them. Certain ones, as iSTo. 14, consist of anbsp;mere giiarl of branches, and most of them are proliferous or composite,nbsp;the branches often having tine, sometimes compound, terminal buds.

PI. LXXVI shows tlie only view that has been taken of the type specimen, Xo. 7, of the U. S. Xational Museum, and Pis. LXXVII tonbsp;LXXIX represent Nos. 14, 24, 83, and 86 of the Yale collection, all ofnbsp;which are more or less fragmentary and aberrant.

Trunks large (38 cm. high, 4 cm. in diameter, 130 cm. in girth in the only complete specimen known), short ellipsoidal or subspherical, of anbsp;light ash color and moderately heavy, bearing numerous large, shortnbsp;branches at and below the center all round, forming conical protuberances, some of which are 8 to 10 cm. long and 12 to 18 cm. in diameter atnbsp;the base, rarely compound, i. e., the branches themselves bearing othernbsp;smaller ones, or two or more arising side by side; branches and all othernbsp;organs radiate, i. e., proceeding in the direction from the center of thenbsp;trunk, those of the equatorial zone horizontal, or making a right anglenbsp;with the axis, those below descending, and those above ascending; leafnbsp;scars arranged in definite rows intersecting one another, somewhat spiral,nbsp;but so placed as to simulate meridians and parellels of latitude, the formernbsp;series, however, rising from left to right and making an angle whichnbsp;vai'ies with the curvature from 5� to 10� with the vertical axis, thenbsp;other series rising from right to left, varying from horizontal to annbsp;angle of 45�; scars varying in shape from subrhombic to nearly truenbsp;rhombs and in size fi'om 10 by 19 cm. or smaller near the summit tonbsp;16 by 22 cm. measured between vertical and lateral angles, which arenbsp;usually quite sharp, the sides straight and the whole very definite andnbsp;symmetrical, usually empty to considerable depth, but partially fillednbsp;by the remains of the leaf bases, which occasionally show punctationsnbsp;representing the vascular bundles; ramentum walls 2 to 5 mm. thick,nbsp;wrinkled on their outer edges, often with a distinct median groove,nbsp;sometimes reduced to thin lamallae with sharp edges, striate within thenbsp;scars in the direction of the petioles; reproductive organs not abundant, the more typical ones mostly in the equatorial zone among thenbsp;branches, which they sometimes resemble, being large with a solid cen-

tral axis surrounded by relatively large bract scars, nearlj^ circular, with a diameter of o cm., other smaller ones scattered among the leafnbsp;scars, only slightly disturbing their arrangement, often abortive andnbsp;reduced to collections of pits in the angles of the walls; armor 0 to 8nbsp;cm. thick, irregularly attached to the ligneous axis, which consists of anbsp;parenchymatous zone 3 cm. thick inclosing a fibrous zone 25 to 35nbsp;mm. thick and divided into two to four exogenous rings; medulla 10 cm.nbsp;in diameter at the base, enlarging upward to more than twice thatnbsp;size, porous in structure, its outer surface marked with longitudinalnbsp;ridges which are interrupted and alternating, forming the bases of thenbsp;medullary rays.

The trunk upon which the above description is almost exclusively based is the one which was called Xo. 3 of the collection obtained fromnbsp;Mr. Cole, and is certainly, in my judgment, artistically the most beautiful cycadean trunk known. I say this deliberately, after having seennbsp;the greater part of all thus far discovered in all countries, and wherenbsp;I have not actually seen the specimens themselves I have in almost allnbsp;cases seen artistic models, or at least excellent photographs or drawings. The specific name is therefore fully justified.

The characters of the internal structure aud the medulla are derived from the large decayed area at the base on one side, which well exposesnbsp;them, leaving the other side still perfect. The total weight of thisnbsp;specimen is 85.73 kilogi ams.

Only one imperfect specimen, viz, No. 78, of the Yale collection could be referred to this species, and this not without some doubt.

Pis. LXXX aud LXXXI represent side, top, and interior views of the type specimen. No. 3, of the tJ. S. National Museum. In the last (PI.nbsp;LXXXI) the specimen was purposely inverted in order to let the lightnbsp;penetrate more thoroughly the exposed interior and bring out thenbsp;structure. PI. LXXXII is a fair view of No. 78 of the Yale collection,nbsp;which was doubtfully referred to this species on account of the shapenbsp;of the leaf scars on certain parts of the trunk, which, however, are notnbsp;well brought out in the photograph.

Trunks small and short, subconical, more or less laterally compressed, smooth and symmetrical, uubranched, light yellowish-brown on the weathered surfaces, fine-grained and fiinty within, about 20 cm.nbsp;high, 18 by 22 cm. in diameter, with a girth of about 00 cm., andnbsp;weighing 13 or 14 kilograms ; organs of the armor nearly horizontal; leafnbsp;scars arranged in two definite series of spiral rows, those from leftnbsp;to right forming an angle near the base of about 70� with the axisnbsp;but curving inward in their upward course so that the angle progressively diminishes to about 30� at the summit, those from right to leftnbsp;19 GEOL, PT 2-39

only slightly curving and making an angle of about 45�; scars very small, almost exactly rhombic, uniform and definite with all the anglesnbsp;sharp, distance between lateral angles 9 to 12 mm. and between vertical ones 6 to 8 mm.; leaf bases present filling the scars to near thenbsp;top, presenting a roughened spongy tissuej rameutaceous walls verynbsp;thin, varying from the thickness of tin foil to 2 mm., presenting a beautiful and regular network of whitened lines over the entire outer surfacenbsp;of the trunk, with a faint commissure or elongated openings betweennbsp;the contiguous plates of the thicker ones; rejiroductive organs notnbsp;abundant nor well developed, the most typical 3 cm. in diameter,nbsp;variable in shape and character, consisting of protuberances with anbsp;depression at the top or ridges with bract scars on the sides, othersnbsp;anomalous, consisting of small projections or elevations, probablynbsp;abortive, none of them greatly disturbing the form or arrangement ofnbsp;the leaf scars; armor 3 cm. thick, separated from the wood by a definitenbsp;line or crack; cortical parenchyma 2 cm.; secondary wood 3 cm., consisting of an outer ring 2 cm. thick and an inner one 1 cm., Avith anbsp;fissure between; medulla elliptical, 5 by 7 cm. in diameter, consistingnbsp;of a homogeneous substance resembling fine yellow sandstone, clearlynbsp;marked oft� from the inner ring of W'ood.

This species is one of the best delijied of all, notwithstanding that it is based uj)on a single specimen, viz, No. 118 of the Yale collection.nbsp;This is an almost perfect trunk, and is only obscured by sand andnbsp;gravel cemented in the scars, so that very little can be seen of thenbsp;summits of the leaf bases. It was collected by Mr. H. F. Wells three-fourths of a mile north of Black�s ranch, about 3 miles north of Black-hawk, South Dakota. Its only affinities are with G. pulcherrima, withnbsp;which it shares the rhombic scars and their definitely arranged rows.

The most perfect side is represented on PI. LXXXIII, showing the arrangement of the scars. The base is shown on PI. LXXXIV, Fig. 1,nbsp;and the summit by Fig. 2 of the same plate.

Trunks moderate sized, profusely and irregularly branched, the primary branches often bearing secondary ones, the branches symmetrical, abruptly contracted at the base into cylindrical turret-shaped projections, dome-shaped at the summit, with a terminal bud at thenbsp;apex composed of small polygonal organs, usually light reddish, soft,nbsp;friable, and of low specific gravity, but sometimes darker, harder, andnbsp;heavier, 20 to 40 cm. high, 25 to 50 cm. in diameter, the branches 10 tonbsp;20 cm. long, 10 to 30 cm. in diameter, 30 to 90 cm. in girth; leaf basesnbsp;slightly ascending; leaf scars very irregularly distributed over thenbsp;surface except of the branches, here sometimes arranged in two sets ofnbsp;spiral rows which intersect each other at about the same angle (60�)nbsp;with the axis of the branch, subrhombio, the upper and lower angles

reduced to mere curves 23 mm. wide, 12 mm. high; leaf bases almost always present, usually projecting, porous; vascular bundles often distinct, set well apart in a row some distance from the margin, with a fewnbsp;others near the center, appearing either as small pits or black dots;nbsp;ramentum walls thin, 1 to 2 mm., usually with a groove or commissure,nbsp;sometimes thickening at the angles and affected with elongated pitsnbsp;and other openings, some of these latter passing into abortive flowernbsp;buds, which constitute all that is known of the reproductive organs ofnbsp;the species; armor 5 cm. thick; woody axis only known in certainnbsp;branches, thin, 2 to 3 cm., and not visibly divided; medulla in one specimen 9 cm. in diameter, black and homogeneous.

Twelve of the specimens of the Yale collection have been referred to this species, viz, Nos. 15, 45, 49, 51, 65, 66, 67, 70, 74, 75, 82, and 85,nbsp;and still much remains uncertain as to the characters. They nearlynbsp;all agree in the most striking feature�the possession of peculiar turretlike branches�but owing to the fragile nature of the rock and thenbsp;sprangling habit of the species all the specimens were badly broken tonbsp;pieces and nothing remains but disjecta membra. Some of these jilantsnbsp;evidently consisted entirely of branches and possessed no trunk propernbsp;which could be regarded as bearing these branches, but usually therenbsp;was a large shapeless mass at the base from which they proceeded iunbsp;all directions. Such was the case in Nos. 45, 51, 66, and 67, some ofnbsp;which must be nearly complete. Nos. 45 and 75 belong to the hardernbsp;and heavier sort, and possibly may not belong to this species. Theynbsp;might be referred to C. minnelcalitensis or �. Marshiana but for differences iu the leaf scars and petioles, which agree with this species. No.nbsp;74 is very anomalous and is only placed here to avoid making newnbsp;species out of deficient material. The turret, if such it was, is reducednbsp;by erosion to a pointed cone without character. The specimen is wornnbsp;to and into the medulla on one side, but the opposite side is well preserved. The leaf scars are typical, but there is a number of large projecting axes looking like horns, and the specimen, laid on the wornnbsp;side, has the shape and semblance of a gigantic �horned toad.� Allnbsp;the other specimens are much alike, and No. 82 is taken as the type fornbsp;most of the characters.

So far as the rock substance, color, and external organs are concerned this species is very close to G. McBridei, but that species is alwaysnbsp;simple and consists of one large, short trunk, constituting a broad distinction which all the numerous specimens of both species do not tendnbsp;in any way to obliterate. In its branching habit it approaches G. min-nekahtensis and G. Marshiana, but the external characters persistentlynbsp;keep it separate from either. In color it somewhat resembles thenbsp;former, but this is all that can be said.

Pis. LXXXV and LXXXVI show the characteristic turret-shaped branches as typified in Nos. 82 and 67. Pis. LXXXVII and LXXXVIIInbsp;give side and base views of the fine specimen No. 49. PI. LXXXIX

represents the anomalous trunk �To. 74, and PI. XO reveals a little of the medulla and axis of Xo. 15.

Pis. xci-c.

1893. nbsp;nbsp;nbsp;Bennettites dacotensis McBride, in part; American Geologist, Vol. XII, p. 249,

1894. nbsp;nbsp;nbsp;Cycadeoidea dacotensis (McBride) Ward, in part: Proe. Biol. Soc. Washington,

Trunks large and very short (25 to 40 cm. high, 25 to 75 cm. in diameter, with a girth of 80 to 250 cm.), more or less laterally or longitudinally compressed, well silicifled but somewhat jiorous or spongy and therefore only moderately heavy, reddish brown in color, occasionallynbsp;bearing small secondary axes which only slightly project; organs ofnbsp;the armor variable but usually radial in direction; leaf scg-rs arrangednbsp;in siiiral rows intersecting each other at various angles, usually forming an angle with the axis in either direction of from 40� to 55�; scarsnbsp;subrhombic or lozenge-shaped, the distance between the lateral anglesnbsp;varying from 22 to 35 mm., that between the vertical angles varyingnbsp;from 13 to 16 mm., nearly always filled with the well preserved basesnbsp;of the leaves which have disarticulated at natural joints leaving anbsp;smooth surface, either convex or concave, or occasionally nearly flat,nbsp;presenting a spongy appearance; vascular bundles of the leaves usuallynbsp;distinct in the form of pits or of dots of darker color arranged in onenbsp;row all round the margin a short distance from it and with a few additional ones near the center; I�amentaceous interspaces thin for the sizenbsp;of the trunks (1 to 4 mm.), compound, i. e., consisting of two or morenbsp;plates of firmer material separated by intervals of loose porous tissue,nbsp;very uniform in character and little distorted, the porous tissue oftennbsp;worn to some distance, leaving fissures divided by thin projecting walls;nbsp;reproductive organs sometimes abundant and conspicuous, but usuallynbsp;rather scarce and poorly defined, some quite large with a cavitousnbsp;funnel-shaped or crater-shaped center, others simulating leaf scarsnbsp;except that they are surrounded by a loose porous tissue in whichnbsp;angular pits occasionally occur, .still others resembling small branches,nbsp;making it difficult in some cases to decide to which class to refer them,nbsp;one which has been cut through the center longitudinally showing anbsp;heterogeneous mass of internal organs resting on a conical receptaclenbsp;25 mm. below its somewhat projecting summit; armor 4 to 8 cm. thick,nbsp;separated from the cortical iiarenchyma by a layer of true bark 6 mm.nbsp;in thickness, of soft texture, its inner surface (exposed in one specimen)nbsp;covered with small pits or punctations and definitely marked by elliptical scars about 9 mm. long and 5 mm. wide, which are aligned horizontally around the trunk, the longer axis being in this direction, the

Qp))er side of tlie scars usually so indistinct as to make them appear kidney-shaped, the lower side and ends consisting of a dark raisednbsp;ring or welt with a groove all round it and exterior to it, the centralnbsp;portion occupied by a number of punctations more or less concentrically arranged; woody axis 9 to 12 cm. thick, of which the parenchyma occupies somewhat more than half and is very porous exceptnbsp;where traversed by the medullary rays of �rmer consistency; fibrousnbsp;zone divided into an outer soft and an inner harder ring, the inner wallnbsp;of the latter conspicuously marked by the scars of the medullary rays;nbsp;medulla in the larger specimens 15 cm. in diameter, but usually elliptical and about 8 by 11 cm., of a uniform porous consistency.

1 name this species for Professor McBride because he was the first to deal with it, although he confounded it with C. dacotensis, and parts ofnbsp;his description apply to the one and parts to the other species. Stillnbsp;his figures are clear and leave no doubt that his fig. 2 belongs here. Innbsp;his description of that figure he says that it belongs to �another individual,� which, of course, would have been otherwise evident, and i)artsnbsp;of his description show that either this or other material in hisgt; handsnbsp;consisted of fragments showing the interior of the trunks, which couldnbsp;not have been exposed in the �large, perfect individual.� Most of hisnbsp;description of the internal parts must have been based on such fragments, and the following words appear to apply entirely to the ])resentnbsp;species; �Leaves not known; tlieir bases as perceived are fusiform ornbsp;lozenge-shape in cross section, one-half inch by one inch in dimensions,nbsp;and show the remains of numerous equally developed fibrovascularnbsp;bundles.�

His specimens seem to have come from exactly the same locality as those x^urchased from Mr. Cole, which I subsequeutly visited in company with Professor and Mrs. Jenney, with Messrs. Cole and Payue asnbsp;our guides. There was found the large branching sjtecimeu, C.minne-Icahtensis, and there, too, I picked up 12 fragments of different sizesnbsp;and shapes. These were numbered in continuation of the Black Hillsnbsp;collection, of which there are 7 nearly perfect trunks, and thereforenbsp;included Hos. 8 to 19. Of these, 6 certainly belong to the present species, viz, Nos. 8, 9,10, 13, 14, and 16. Two of these fragments. Nos. 10nbsp;and 14, are found on comparison to fit together, and therefore, of course,nbsp;to belong to the same trunk. When placed in their proper positionnbsp;they constitute the greater i^art of it, but a large segment is missingnbsp;from one side. Among these specimens, all differently broken, a muchnbsp;larger number of characters are exposed than could be seen in anynbsp;number of j^erfect trunks. Wherever two or more display the same i)artsnbsp;they are in substantial agreement, and it is therefore assumed thatnbsp;such features as are only visible in some one specimen would be foundnbsp;in the rest if the jrroper parts could be exposed. The beautiful markings on the inner surface of the liber zone, as above described, are tonbsp;be seen only in specimen No. 16 (see PI. XCIII). That all trunks of the

species were of the short, conical shape indicated by Nos. 10 and 14 when placed in their natural position can not, of course, be demonstrated, but the other specimens do not negative this view.

Professor McBride remarks that �the present species is near Bew-nettites Oibsonianus Carr., from which it may be distinguished by greater size and by the fact that in our species the flbrovascular bundles of thenbsp;leaf stems are of uniform size and distribution, and do not form a horseshoe shape in cross section, as is said to be the case in the Englishnbsp;species.� In this last one would suppose he was confounding the undivided vascular bundle as it appears in the axis, and especially in itsnbsp;passage through the cortical layer (cf. Oarruthers�s pi. Ivii, fig. 3, innbsp;Trans. Linn. Soc., Vol. XXVI) before it divides, with the form assumednbsp;by the numerous strands that enter the petiole and appear as smallnbsp;dots on a cross section of the latter (cf. loc. cit., pi. Iviii, fig. 2). Neithernbsp;in the American Geologist nor in the Bulletin of the Laboratory of thenbsp;State University of Iowa do these strands show elearly in fig. 2, still Inbsp;think I can detect them; but in nearly all our specimens these bundlesnbsp;are very clearly shown, and they do agree remarkably well with thosenbsp;of Carruthers�s figure (loc. cit., pi. Iviii, fig. 2). Still I should hesitatenbsp;to refer the American forms to G. Gibsoni on this character alone, andnbsp;having myself examined the British specimen I do not think it is verynbsp;close in other respects (cf. Sixteenth Ann. llept. �. S. Geol. Surv., Pt.nbsp;I, p. 487).

The abseneeof perfect trunks of this species in the National Museum collection is not due to its rarity in the Black Hills, as I was satisfiednbsp;after examining the large number of fragments picked up by myself,nbsp;but to the frailty of the species. There is in fossil cycads certainly anbsp;close connection between the mineral constitution and the originalnbsp;nature of the tissues, and both vary with the species much as differentnbsp;kinds of wood differ in their qualities of hardness, durability, tenacity,nbsp;etc., in our living forests. Accordingly the substance of the rock innbsp;this species is always soft, porous, and light, easily worn by attrition,nbsp;and therefore frail. Moreover, there is a tendency to early decay of thenbsp;medulla and woody axis, which caused many of the trunks to becomenbsp;hollow before they were entombed. This made compression and general destruction easy and accounts for the difficulty in securing goodnbsp;specimens.

In view of these facts, I was not surprised to find a large number of specimens of this species in the Yale collection. There are no less thannbsp;thirteen which I have so referred, although several of these are verynbsp;abnormal and doubtful. The ones so classed are Nos. 8, 19, 23, 26, 27,nbsp;29, 38, 42, 46, 53, 73, 76, and 110. No one of these is absolutely complete, and the greater part of them are mere fragments. In the majority of cases the specific determination is clear at a glance, and this isnbsp;true even of the smaller fragments. No. 19 is a typical and nearlynbsp;complete trunk, weighing 51.46 kilograms, and No. 23 is by far thenbsp;most perfect specimen of the species known to me. It weighs nearly

59 kilograms, but there is a vast cavity at the summit. No. 76 is also nearly complete aud a hue example, weighing 23.59 kilograms. Therenbsp;are four dwarf specimens. Nos. 26, 29, 42, and 53, which, though nearlynbsp;perfect, must be immature trunks if they belong here. They di�er toonbsp;much from each other to constitute a specific group, and I have beennbsp;obliged to treat them as young, dwarf, or aberrant forms of this species.nbsp;Nos. 26, 29, and 42 have each a good terminal bud, the only such seennbsp;in the species. No. 53 is very small, only 11 cm. high, weighing onlynbsp;1.57 kilograms, short-conical, and very symmetrical. It represents thenbsp;species in miniature, and is doubtless undeveloped.

Only one of the specimens of the Yale collection from the Blackhawk region belongs to this species, viz. No. 110, which consists of nearlynbsp;half of a large trunk showing the much worn outer surface with deepnbsp;holes, which are often united a short distance within by the decay ofnbsp;the walls so as to produce communicating chambers. The opposite sidenbsp;exposes a large hollow, or trough, consisting of the inner wall of thenbsp;woody zone. It also shows the attachment of the armor and the underlying axis in an exceptional manner.

PI. XOI shows the broad side of the trunk resulting from joining Nos. 10 and 14 of the U. S. National Museum collection, which werenbsp;found to lit together aud make considerably more than half of the trunk.nbsp;This also shows the full height, as we have the true base and all thatnbsp;was left of the summit after the decay of the terminal bud. The scarsnbsp;are clearly shown on the surface, but less so than in fragment No. 9, anbsp;portion of the surface of which, enlarged, is shown on PI. XOII. Innbsp;PI. XCIII we have a clear view of the inner wall of the liber zone ornbsp;true bark, which is marked by scars of a different pattern from anynbsp;elsewhere observed.

No. 23 of the Yale collection is perhaps the most complete trunk of this species known, aud has been illustrated from the broad side, thenbsp;hollow summit, aud the base on Pis. XCIV-XCVI. The inner wallnbsp;of the armor is exposed in No. 27, aud this is shown on PI. XCYII.nbsp;PI. XCVIII, Fig. I, represents the small trunk. No. 29, of the Yale collection, which may be a dwarf form of this species. It will be noticednbsp;that dwarf forms are the only specimens known in which the terminalnbsp;bud is preserved. This might happen in immature specimens, when innbsp;all old trunks this organ would decay too rapidly to become silicifled.nbsp;Fig. 2 shows the smallest specimen of the species, and, indeed, there isnbsp;much doubt as to whether it belongs here, but it bears too many evidences of being a very young trunk to make it safe to call it a newnbsp;species, and the characters, so far as they go, point to G. McBridei.

Pis. XCIX and 0 represent the outer (Fig. 1) and inner (Fig. 2) surfaces of the specimen No. 110 from the Blackhawk region, abovenbsp;described.

All the specimens except the one above mentioned have been found in the Minnekahta region.

Trunks very large, profusely branched, the primary branches often bearing secondary ones, the whole individual frequently consisting ofnbsp;branches, sometimes with a sort of common base, the branches irregularnbsp;in size, form, and direction, making shapeless or grotesqne objects;nbsp;summits of the branches rounded, bearing small polygonal scars withnbsp;depressed or cavitous centers separated by deep channels as if fromnbsp;the disappearance of the walls, or filled with the bases of the apicalnbsp;leaves often set in a circular, smooth, flattened area, and having anbsp;small conical protuberance or terminal bud at the center; rock substance hard, heavy, and dark colored; general external appearancenbsp;rough and massive; forms very variable in size and difficult to measure, the largest attaining 91 cm. in its greatest dimension, the lateralnbsp;generally greater than the vertical dimensions when standing on thenbsp;base, the former often 50 to GO cm., the latter 30 to 40 cm.; branchesnbsp;15 to 30 cm. long, 10 to 40 cm. in diameter, and often over a meter innbsp;girth; organs of the armor ascending on all the branches; phyllotaxynbsp;usually so disturbed as not to be traceable, but consisting of at leastnbsp;one series of spiral rows of scars passing from right to left at an anglenbsp;of about 75� with the axis of the branch; leaf scars of medium size ornbsp;small for the size of the trunks, normally subrhombic, but varyingnbsp;from triangular, or with a mere groove to represent the upper angle, tonbsp;nearly rhombic, 15 to 30 mm. wide, 7 to 15 mm. high, averaging 12 bynbsp;25 mm. for the body of the trunk and 10 by 18 mm. for the branches,nbsp;usually empty to considerable depth, sometimes filled with the leafnbsp;bases, which either present a smooth concave surface or a rough projecting surface formed in iiart by rows of pointed elevations consistingnbsp;of the exposed extremities of the vascular bundles lying on the sidesnbsp;of a central conical protuberance the apex of which is formed in part ofnbsp;the more interior strands; ramentaceous interstices usually thick, 5 tonbsp;15 mm., hard, roughened, wrinkled, or grooved, often highest nextnbsp;so the scars, sometimes thinner with only a median line; reproductivenbsp;organs generally abundant on the body of the trunk and largernbsp;branches, large, 7 cm. long in a circumferential direction, 5 cm. high,nbsp;conspicuous, either projecting or cavitous and crater-shajied from thenbsp;decay of the essential organs, surrounded by concentric rows of largenbsp;bract scars, sometimes more rare and smaller; armor 4 to 7 cm. thick,nbsp;but difficult to observe except on the branches where it has littlenbsp;significance; cortical parenchyma 3 to 4 cm.; fibrous zone 2 to 4 cm.nbsp;with two rings; medulla sometimes seen at the compound base, 12 cm,nbsp;in diameter, often decayed so as to leave a large cavity, its surfacenbsp;exposed in one specimen showing the scars of the medullary rays innbsp;the form of elongated ridges increasing in thickness upward and terminating in a sharp point.

This magiiificeut species was first clearly made known to me in the Yale collection, where it is represented by five, and probably six, specimens. These are Nos. 4, 11, 33, 44, 47, and 79. The doubtful ones arenbsp;Nos. 33 and 79. These are single branches of ranch larger trnnks, andnbsp;their characters are somewhat aberrant. Of the other five there is nonbsp;doubt, as they agree in all their characters. No. 11 is taken as the type.nbsp;It is larger than any of the rest, and the next largest specimen in thenbsp;Yale collection, weighing 221.35 kilograms, and therefore holding thenbsp;third rank in this respect among the cycads of the world. It hasnbsp;the form of a huge animal, has five primary branches, and when placednbsp;in the position in which it probably grew four of these, with the massnbsp;to which they are attached, constitute a sort of forepart, with head,nbsp;thorax, and fore.limbs, while the other represents the hinder part andnbsp;is aligned in the opposite direction. Between these parts is a constriction dividing the two systems. It is very complete, so much so that itnbsp;has furnished few of the internal characters.

Nos. 4 and 47 are also large trunks, weighing, respectively, 52.62 and 34.93 kilograms, and the other fragments snpirlement the more perfectnbsp;specimens so as to make a pretty fnll description of the species possible.

I have named the species in honor of Professor Marsh, to whose energy and munificence this great collection is wholly due.

When engaged in examining and describing these specimens in the Yale collection I supposed that none existed in the U. S. Nationalnbsp;Museum, but on revising all my previous descriptions in the light ofnbsp;the new material I discovered that I was mistaken, and that specimen No. 15 belongs to this species. I had referred it with doubt tonbsp;(J. colossalis, and under that head had made the following remark: �Thenbsp;only other specimen in the collection of the U. S. National Museumnbsp;that I can refer to this species is the fragment No. 15, collected bynbsp;myself in 1893 on the same spot where the others were found. Thisnbsp;is a very irregular block or segment broken from near the top of anbsp;great trunk. It is similar in mineral character to No. 6, and the leafnbsp;scars and other organs agree well with the upper parts of that specimen. The fractures are downward, but follow the jdane of the petioles,nbsp;which are here erect. In No. 15, however, two large and nearly equalnbsp;branches, whose axes were nearly at right angles to each other, arenbsp;represented. Viewed from the broken sides, the two axes are clearlynbsp;seen in contact, having a gnarly appearance, such as is normally produced at the junction or crotch between two branches.�

This branching character, as I was well aware, does not belong to the large, perfect specimen, but, having no others, I thought it possible thatnbsp;some of the small secondary axes might in other cases become primarynbsp;branches; but after seeing so many other specimens of G. colossalis allnbsp;agreeing in this respect, and also a large number of the present speciesnbsp;also all agreeing and exhibiting no tendency to vary in the directionnbsp;of the other species, it became obvious that the branching forms all,

belonged to one species and the simple ones to another. The specimen No. 15 clearly belongs to the branching species, and now it is easy tonbsp;see other specific differences.

Pis. CI-CIII furnish a fairly good idea of the great type specimen, No. 11. PI. OIV represents one of the large limbs torn from a specimennbsp;of unknown size, No. 47. Finally, PI, GV gives us a side view of No. 33,nbsp;the anomalous character of whose scars has been described. Ofnbsp;course, the peculiarity in the vascular bundles eould not be expected tonbsp;appear in a photograph.

Trunks large, forking above, or sometimes with a third branch, simple below, laterally compressed, eccentric, light colored, soft and of low specific gravity, 35 to 45 cm. high, 25 to 30 by 35 to 40 cm. in diameter,nbsp;90 to 110 cm. in girth; organs of the armor mainly horizontal; leafnbsp;scars subrhombic, or somewhat triangular, the vertical angles generallynbsp;rounded, the lateral acute, variable in size, averaging 15 by 25 mm., thosenbsp;on the branches smaller, or sometimes nearly as large, empty; ramenta-ceous walls variable, usually thin, 1 to 5 mm., much thicker in thenbsp;angles, firm in texture, grooved or divided into two or three plates; reproductive organs few, large, elliptical, 4 to 7 by 7 to 10 cm. in diameter,nbsp;either set in depressions or somewhat elevated, surrounded by bractnbsp;scars, either cavitous in the center or solid, the larger ones simulatingnbsp;small branches; armor 4 to 7 cm. thick; cortical parenchyma 7 cm.,nbsp;clearly distinguishable from the darker zone of wood 0 cm. in thickness; medulla elliptical, 9 to 11 cm. in diameter.

This species is thus far represented by only two specimens, viz. Nos. 18 and 60, of the Yale collection, the latter of which is in such a complete state of preservation that little can be known of its internalnbsp;structure. It is distinguished from all other trunks known to me by anbsp;true dichotomy, consisting of a simple trunk with two nearly equalnbsp;erect branches and a natural junction or crotch at their point of separation. The axis is far to one side and the trunk is flattened on thatnbsp;side, the entire true base being lateral and the trunk, standing on a falsenbsp;base, belonging to the armor, but naturally flattened in transversenbsp;direction. These peculiarities were doubtless the result of the positionnbsp;in which the trunk originally grew among rocks. Besides this striking characteristic, the light color and soft constitution of the rock, asnbsp;well as the form Und arrangement of the scars, ramentum walls, reproductive organs, etc., distinguished this from all other cycadean trunks.nbsp;It is a fine specimen, and weighs 49.9 kilograms.

No. 18 consists of two nearly equal branches and one somewhat smaller, arranged in a triangular cluster. Two of them are flat on one

side from growing against rocks. The trunk jjroper can scarcely be said to be represented. The two larger branches are each about 30 cm.nbsp;in diameter and 23 cm. long, with rounded summits forming somethingnbsp;analogous to terminal buds. Fractures about the lower portion yieldnbsp;elements of internal structure, but they relate to the branches only.nbsp;The external surface is beautifully preserved. This specimen weighsnbsp;66.22 kilograms.

Two views of specimen iso. 60 were taken, one of the rounded outer surface or back, PI. OVI, and the other of the opposite flat side, PI. OVIl,nbsp;within which the true base, set on one side, wholly falls. The indications are that the trunk grew with this side against a vertical rock andnbsp;was connected with the soil beneath it.

PI. OVIII is a view of the specimen No. 18, seen from above, and PI. CIX shows it from the base.

Trunks rather large, ellipsoidal, 34 to 48 cm. high, elliptical or nearly circular in cross section, 30 to 39 cm. in diameter and 90 to 118 cm. innbsp;circumference at the thickest part, simple, the apex studded with smallnbsp;polygonal scars-and presenting a smooth disk with a central elevation;nbsp;rock substance dark brown in color and moderately heavy; organs ofnbsp;the armor except the very lowest manifestly ascending; leaf scarsnbsp;arranged in two series of more or less distinct spiral rows, those passing from left to right forming an angle of 75� and those from right tonbsp;left of 45� to the vertical axis; scars subrhombic, varying from almostnbsp;rhombic to nearly triangular with rounded angles, large, averaging 22nbsp;mm. wide and 13 mm. high, but ratio of width to height variable, emptynbsp;to a depth of 2 to � cm.; ramentaceous walls usually thick but verynbsp;variable, doubly grooved or wrinkled, cracked or fissured, often pittednbsp;by the scars of small bristles or perulse; fruiting axes numerous, small,nbsp;most or sometimes all of their surface occupied by bract scars, centralnbsp;portion correspondingly small, generally cavitous from the disappearance of the essential organs, which appear to have often been immaturenbsp;or abortive; armor about 6 to 7 cm. thick; cortical parenchyma 3 cm.nbsp;thick; fibrous zone 2 cm., consisting of two rings of wood;, medullanbsp;about 9 cm. in diameter.

This is a very handsome species of which the type specimen was purchased of Mr. F. H. Cole, for whom the species is named. That specimen weighs 63 kilograms.

The Yale collection contains nine specimens that I was obliged to refer to this species. These are Nos 12,20,25,28,48,52,57,68, and 80.nbsp;Of these Nos. 25 and 80 are small and either dwarfed or immature, andnbsp;Nos. 28 and 52 are small fragments. The rest are fairly typical and

furnish good characters. No. 48, though small, weighing only 29.49 kilograms, is perhaps the most typical. No. 57, though not complete,nbsp;weighs 56,24 kilograms, and was doubtless originally quite the equal ofnbsp;the National Museum type. No. 12 has an unusual number of fruitingnbsp;axes.

PI. CX shows a side view of the type specimen. No. 2 of the �. S. National Museum, and PI. OXI that of the very similar trunk. No. 48 ofnbsp;the Yale collection. The fragment No. 12 of the Yale collection represented on PI. OXII is somewhat anomalous if not siiecifically doubtful,nbsp;but can not be referred to any other known species.

Trunks medium sized, laterally compressed, usually enlarging from the base upward to n�ar the summit but sometimes subcylindrical, 30nbsp;to 55 cm. high, 65 to 85 cm. in average girth, 20 by 25 cm. to 25 bynbsp;35 cm. in diameter, light or darkish brown in color, not specially firmnbsp;or heavy, bearing few or not any secondary axes; organs of the armornbsp;horizontal; phyllotaxy rather obscure, but scars arranged in imperfectnbsp;spiral rows, chiefly subrhombic, but varying to rhombic or triangular,nbsp;much distorted in the specimens in hand, but where clearly shown 10nbsp;to 16 mm. high and 16 to 31 mm. wide, empty to some depth, theirnbsp;bottoms filled with the partially decayed remains of the petioles;nbsp;ramentaceous interstices rather thin but variable, usually with a morenbsp;or less distinct commissure; reproductive organs or their remainsnbsp;numerous and conspicuous, often projecting considerably beyond thenbsp;general surface in the form of protuberances or terete spongy cylinders,nbsp;often decayed, leaving largecavities more or less crater-shaped or funnel-shaped, the interior sometimes definitely grooved or marked, surroundednbsp;by numerous, sometimes large, triangular involucral bract scars; armornbsp;varying in thickness from 2 to 7 cm., attached by an irregular linenbsp;or thin layer of bark to the cortical parenchyma which is 1 to 2 cm.nbsp;thick and incloses a fibrous cone of about the same thickness, whichnbsp;is divided into two or three rings; medulla less compressed than thenbsp;outer parts, 6 to 10 cm. in diameter.

The only specimens that certainly belong to this species are Nos. 4 and 5 of the collection purchased from Mr. Cole. The description ofnbsp;the internal parts is chiefly based on No. 5, which is the smallest ofnbsp;that collection and has been cut longitudinally through the axis, one ofnbsp;the halves cut transversely 12 cm. above the base and the surfacesnbsp;polished. These sections furnish clear views of the organs of the armornbsp;and of the relations of the armor to the underlying iiarts. The specificnbsp;identity of the two specimens is based on the external characters,nbsp;which substantially agree. No. 4 weighs 33.11 kilograms and No. 5,

22.22 kilograms. I name tlie species for the ranchman, Mr. Payne, who originally discovered the cycads of that region and from whom Mr.nbsp;Cole obtained them. He it was, moreover, who hnally guided us tonbsp;the locality after Mr. Cole had vainly sought to take us to it the previous day, missing the way notwithstanding that he had been at thenbsp;spot.

In the Yale collection there are two specimens, l^os. 58 and 69, which I have doubtfully referred to this species, although some of thenbsp;characters are different from those above described. They are verticallynbsp;instead of laterally compressed. If this is due entirely to pressure ofnbsp;the superincumbent mass after entombment, it has no systematic valuenbsp;and depends upon the position occupied by the sijecimen; but eminentnbsp;authorities have insisted that it is a condition of growth. I am inclinednbsp;to think that this may be true in some cases, but that the formernbsp;explanation is the chief one.

The Yale specimens are both smaller than either of the National Museum types. No. 69 weighing 20.86 kilograms, and No. 58, which isnbsp;dwarf, abnormal, and perhaps immature, 5.33 kilograms.

Pis. CXIII and CXIV give side and base views of the type specimens Nos. 4 and 5 of the 17. S. National Museum, and PI. CXY represents thenbsp;polished surface of the interior of No. 5, bringing out the relations ofnbsp;the various tissues in 4 very satisfactory manner.

1893. Cycadeoidea Paynei Ward, iu part: Proc. U. S. Nat. JIu.s., Vol XXI, pp. 212-213 (quoad No. 77 of the Yale collection).

Trunks medium sized or small, cylindrical-conical, somewhat laterally compressed, dark colored, moderately hard with medium specific gravity, rough or jagged on the outer surface, unbranched, about 40 cm.nbsp;high, 21 by 25 cm. in diameter at the middle portion, 70 to 80 cm. innbsp;girth; organs of the armor about horizontal, at least in the middle part;nbsp;phyllotaxy not traceable; leaf scars normally subrhombic and narrownbsp;but much distorted by the fruits, often triangular, sometimes with thenbsp;upper side downwardly curved, 20 to 25 mm. wide, 12 to 20 mm. high;nbsp;leaf bases present but not reaching the surface, porous or spongy without visible bundle scars; ramentum walls thin, 1 mm, or less, muchnbsp;broken down in the specimens, with or without an obscure mediannbsp;line; rejiroductive organs abundant over all parts of the trunk, covering half of the surface and distorting all other organs, large and somewhat elliptical but sometimes nearly circular, 25 to 35 mm. iu diameter,nbsp;often cavitous with a very definite bowl-shaped interior, the bottomnbsp;smooth and usually raised like that of a blown bottle, or .with a boss ornbsp;button in the center, i. �e., the receptacle of the spadices rising up with

a depression all round it, sometimes resembling a saucer inside tbe larger bowl, the central boss or button sometimes with a large, deepnbsp;slit nearly transverse to the axis of the trunk or in line with the majornbsp;axis of the cross section, this slit occasionally replaced by a sharpnbsp;ridge or by a few pitsj fruits often partly or wholly preserved, obovate,nbsp;sometimes rising above the general surface and convex at the summit,nbsp;either smooth or granular from the exposed extremities of the numerous densely matted seeds; spadices surrounded by involucral bracts,nbsp;consisting of the receptacle above described as a central boss or button from which rise numerous seminal peduncles of varying lengths,nbsp;the central ones longest and ascending to the summit, the more lateralnbsp;ones proceeding outward and terminating at the periphery in such anbsp;manner as to form a cylindrical body with a rounded outer extremity,nbsp;each peduncle terminating in a single seed; seeds 1.5 mm. to nearly 2 mm.nbsp;in diameter, oblong in shape, 5 mm. long, surrounded by an opalizednbsp;double seed-coat, their combined mass forming a somewhat irregularnbsp;layer over the whole upper jiart of the fruit, extending downward tonbsp;about the middle, each seed containing a number (G to 12) of relativelynbsp;large spherical bodies, sometimes opalized like the seed-coats, possiblynbsp;representing the archegonia; armor thin, about 4 cm. thick; woodynbsp;zone not visibly divided, 4 cm. thick; medulla elliptical in cross section,nbsp;4 by 6 cm. in diameter.

At the time I described iMo. 77 of the Yale collection in June, 1898, the specimen was almost wholly covered with an incrustation of limenbsp;and very little could be learned of its nature. Suflicient, however, wasnbsp;visible to indicate that it possessed an especial interest. The peculiarnbsp;granular structure of some of the fruits could be seen, and from suchnbsp;examination as I was able to make I derived the description that Inbsp;gave on page 213 of the Proceedings of the United States Nationalnbsp;Museum, Yol. XXI. I included it provisionally and doubtfully in G.nbsp;Paynci, from the general form and appearance, although there werenbsp;differences even in the external character which were there pointednbsp;out, and I was careful not to include the peculiarities observed in thenbsp;rejiroductive organs in the descri2ition of that species, because I anticipated that these and the other differences might require it to benbsp;removed from G. Paynei when a fuller study of them should be made.

On my next visit to New Haven in November, 1898, to study a fresh invoice of cycads sent by Mr. Wells, I found another specimen. No. 131,nbsp;which exhibited most of the external characters of No. 77 and hadnbsp;similar fruits, very few of which, however, contained the whole of thenbsp;spadix. In a number of cases this had fallen out, leaving the bowlshaped cavity, but with some of the seminal peduncles adhering to itsnbsp;sides and terminating in the little elongated sockets in which the seedsnbsp;had lain. This at once revealed to me the true nature of the fruitsnbsp;of No. 77, and I thereupon xffaced that specimen in a vat of acid andnbsp;removed the coating of lime. The specific identity of the two specimens

was then manifest and it became clear that the small bodies described in the latter and erroneously taken for the silicifled cores of the seminalnbsp;peduncles were the seeds themselves.

I endeavored to impress upon Professor Marsh the great importance of this discovery and the urgent necessity of having sections made ofnbsp;this first case thus far discovered of seeds preserved in the trnnk of annbsp;American cycad. The extreme rarity of such cases justified thisnbsp;exceptional interest, and I succeeded in arousing in Professor Marsh anbsp;part of the interest that I felt in the matter.

It chanced that Mr. George E. Wieland was at the time working in the Peabody Museum. He had himself collecded a considerable number of cycads, had spent one day with Mr. Wells and myself in thenbsp;Blackhawk region, and was greatly interested in the general subject.nbsp;He had had considerable training in the technique of section cutting,nbsp;and, with Professor Marsh�s approval, he proceeded to make some sections of one of the best spadices of No. 77, which was easily detachednbsp;from near the fractured margin of the trunk. The longitudinal sectionnbsp;first made revealed the whole nature of the fruit and showed its essential identity with the fruits of G. Oihsoni, that had been the subject ofnbsp;such prolonged and exhaustive studies on the part of Oarruthers andnbsp;Solms-Laubach, in Europe. It proved also to be at least genericallynbsp;identical with the celebrated fruit called Bennettites Morierei, from thenbsp;Jurassic of Calvados in Prance, so beautifully monographed bynbsp;Professor Lignier.

A cross section was also made while I was at New Haven, and from these sections I was able to write the description of the internalnbsp;structure of these fruits as given above.

I was convinced that other specimens, both in the Yale collection and in that of the United States National Museum, would show perfectnbsp;fruits if properly treated, and I took that occasion to urge Professornbsp;Marsh to inaugurate a systematic study of the Yale collection fromnbsp;this point of view, which he did, and Mr. Wieland has continued thenbsp;work so auspiciously begun. It is therefore with great pleasure thatnbsp;I dedicate this species to him, the first to bring to light the internalnbsp;structure of the reproductive organs of the fossil cycads of America.

This species is therefore founded on the two type specimens. Nos. 77 and 131 of the Yale collection. No. 77 is smaller above than below, andnbsp;is naturally oblique at both base and summit, having lost nothing. Itnbsp;is jagged on all sides with its unequal walls and protruding fruits. Itnbsp;is 32 cm. high. Its major diameter varies from 23 to 25 cm., and itsnbsp;minor from 16 to 21 cm. It has a girth near the base of 74 cm. and atnbsp;the summit of 66 cm. Its weight is 21.09 kilograms.

No. 131 is larger than No. 77. It is long-conical, very obliquely truncated above so as to want the apex entirely, also irregularly broken across below, but the lowest part probably shows the true base, which

was little if at all contracted. It is elliptical in cross section, and a number of pieces broken out of one side of the base have been saved andnbsp;accompany the specimen. Its present height is 40 cm., which, owingnbsp;to the obliquity of the fractures, probably represents its full length.nbsp;The longer diameter near the base is 26 cm. and the shorter one 21 cm.nbsp;The girth at the base is 70 cm., and at a point just below the uppernbsp;fracture 66 cm. It weighs 22.22 kilograms.

PI. OXVI shows a side view of trunk Xo. 77. A number of fruits are clearly brought out.

Trunks small, subcouical, simple, very rough on the surface, light brown varying to whitish, dark with white streaks within, moderatelynbsp;heavy, about 20 cm. high, nearly the same in diameter, and 70 cm. innbsp;circumference; organs of the armor somewhat declined throughout;nbsp;phyllotaxy not traceable; leaf scars anomalous in having the uppernbsp;angle much sharper than the lower, the reverse of the usual case andnbsp;only elsewhere observed in G. wsoiite, lower angle reduced to a groove,nbsp;a curve, or a straight line, lateral angles always sharp; scars small, 12nbsp;to 25 mm. wide, 10 to 15 mm. high, subrhombic; leaf bases presentnbsp;usually projecting 5 to 10 min. above the walls, presenting a lightnbsp;brown, very spongy and porous surface, without evidence that any ofnbsp;the pores represent the scars of vascular strands; ramentaceous interstices thin, 1 to 5 mm., dark reddish brown, sunk to varying depthsnbsp;among the projecting leaf bases and other organs, scaly and laminatednbsp;with crooked and twisted plates; reproductive organs as numerous asnbsp;the leaf scars, projecting much beyond the petioles, sometimes 3 cm.nbsp;high, solid or variously broken and jagged, occasionally somewhat cav-itous, scarcely showing any involucral scales, but in addition to all thenbsp;other organs described are small angular bracts, mostly broken down,nbsp;presenting sharp edges and jirojections over the surface, intermediatenbsp;in character between scales and leaves, properly to be classed as bristles or iierulaj; all the diiferent projecting organs giving the trunk anbsp;ragged and bristling appearance; armor, including projections, 6 cm.nbsp;thick, the vascular strands traceable far into the woody zone and innernbsp;limit not definite; parenchymatous layer 15 mm. thick, penetrated bynbsp;the whitened leaf bundles; secondary wood 2 cm. thick, consisting ofnbsp;two nearly equal rings, the outer white, the inner black or dark bluenbsp;in the only specimen known; medulla 6 cm. in diameter, dark, finegrained and homogeneous.

This species is based on the single sxiecimen, Xo. 104 of the Yale collection, which is somewhat less than half of a trunk that divided along a vertical plane from top to bottom almost as smooth and even as ifnbsp;sawn through by a gang saw, exposing the interior in an admirable

manner. Its only affinities are with G. Paynei, and the specimen, though smaller, has a remarkable resemblance to No. 5 of the U. S.nbsp;National Museum (cf. Pis. CXIV and GXV), which was cut throughnbsp;on the same plane as this siiecimen. The resemblance is, however,nbsp;more apparent than real, and the descending leaves and especially thenbsp;inverted scars clearly exclude it from that species. Add to this thatnbsp;no specimens of G. Paynei have been found elsewhere than in the original Minnekahta locality, and the improbability of this belonging to thatnbsp;species is very great. It is too perfect a specimen to class as undeterminable, and there seems no course left than to treat it as constitutingnbsp;a new species.

Fig. 1 of PI. CXVII represents the rough outer surface and Fig. 2 the inner face.

Trunks medium sized, unbranched, somewhat elliptical in cross section, subcylindrical or subconical; rock substance light colored, moderately hard and heavy; height of trunks 30 to 40 cm., diameter 30 to 35 cm., girth about 1 meter; organs of the armor nearly horizontal;nbsp;leaf scars irregularly distributed over the surface, very variable innbsp;size and shape, rhombic or subrhombic, in the latter case havingnbsp;the more acute angle above and the more obtuse one below, i. e.,nbsp;the opposite of the normal condition, 15 to 25 mm. wide, 8 to 15nbsp;mm. high, sometimes empty to some depth, but in some such casesnbsp;the summits of the leaf bases showing the vascular bundles in thenbsp;form of little rods or pins projecting upward and forming a row allnbsp;round the leaf bases close to the margin with others near the center,nbsp;about 18 to each leaf; leaf bases sometimes projecting in the form ofnbsp;small cones, in which cases the bundles can be seen either as black dotsnbsp;or as little protuberances around the sides of the cones; ramentumnbsp;walls thin but variable, 1 to 4 mm., firm and sharp on the edges ofnbsp;the scars, grooved along the middle; reproductive organs abundant,nbsp;disturbing the phyllotaxy, tending to congregate and blend together,nbsp;presenting a rough surface, usually projecting, rather small and withnbsp;few bract scars; armor 4 to G cm. thick; cortical parenchyma 2 to 3 cm.;nbsp;fibrous zone 15 to 30 mm., with two or three rings, the outer either preserved and showing fine-grained structure or much decayed, in eithernbsp;case conspicuously partitioned off by the medullary rays, the othersnbsp;also showing woody wedges; medulla 8 by 12 cm. in diameter at thenbsp;base, enlarging upward, hard and homogeneous in structure.

This species is founded on two specimens in the Yale collection. Nos. 50 and G4, chiefly the latter. No. 50 being only a small fragment.nbsp;The characters can not be forced into any other species, especially thenbsp;19 GEOL, PT 2--40

inverted leaf scars and the peculiar habit of the vascular bundles in the petioles. In Ho. 33, which is a branch of a trunk of the type ofnbsp;Ho. 11, and has been referred to C. Marshiana, this latter peculiarity isnbsp;nearly repeated, but this happens in no other specimen of that species.

Ho. 04 is the lowex- part of a truuk irregularly broken across the top and down one side to near the middle. The apex is therefore unknown.nbsp;It is this specimen that has furnished all the external characters, butnbsp;Ho. 50 shows precisely the same characters so far as it goes, and addsnbsp;somewhat to the knowledge of the internal parts. Ho. 04 weighs 24.95nbsp;kilograms and Ho. 50, 3.29 kilograms.

Pi. CXVIII and Fig. 1 of PI. CXIX illustrate the trunk. Ho. 64, but the views can not be said to be very satisfactory. Pig. 2 of PI. OXIXnbsp;affords a much better idea of the leaf scars as they are seen on thenbsp;outer surface of the smaller fragment. Ho. 50. Their inverted form isnbsp;here made clear, though some appear as true rhombs.

Trunks medium sized, conical or ellipsoidal, simple or with a few small secondary axes, well silicihed, moderately hard and heavy, reddish brown without, dark or nearly black within; organs of the armornbsp;generally ascending; phyllotaxy not traceable in any of the specimens;nbsp;leaf scars subrhombic, variable in size, 16 to 25 mm. long, 10 to 16 mm.nbsp;high, usually filled by the leaf bases; bundles not visible; ramenta-ceous interspaces thin, less than 2 mm., roughened without, white within,nbsp;eontrasting strongly with the black petiolar substance in longitudinalnbsp;section; reproductive organs rare, slightly protruding, usually havingnbsp;remains of the organs preserved, occasionally decayed so as to leavenbsp;openings, obscure from without, distinct in sections longitudinal tonbsp;them, penetrating to a depth of 6 cm.; the substance above the fruitnbsp;light colored; fruit dark, elliptical or ovate, nearly homogeneous andnbsp;showing no structure, subtended by strong iuvolucral bracts andnbsp;crowded by a mat of chaff probably consisting of the summits of thenbsp;interseminal scales; seeds not detectable; armor 5 to 8 cm. thick, irregularly joined to the woody axis, the outer or parenchymatous portion ofnbsp;which, to a thickness of 3 cm., is more or less decayed in most of thenbsp;specimens; fibrous zone divided into two rings, each about 15 mm.nbsp;thick, the innermost very firm and fine-grained, its inner wall (exposednbsp;in two specimens) regularly marked by the scars of the medullary rays,nbsp;the scars consisting of conspicuous elongated depressions arranged innbsp;longitudinal rows at equal distances (1 cm.) from one another; thenbsp;scars nearly the same distance one above another but alternating sonbsp;as to form diagonal rows crossing the vertical ones at an angle of nearlynbsp;45�; inner face of the second ring of wood (exposed over a small area

in one specimen; nearly smootli but faintly striate in a horizontal direction, marked with smaller, more distant scars; medulla (represented only in one small disk-shaped specimen from near the top of anbsp;trunk, and here thoroughly crystallized) scarcely known.

Four of the fragments jiicked up by me belong to this species. They are Nos. 11, 12, 17, and 18. No. 11 is a large block weighing over 7nbsp;kilograms, showing considerable of the external surface, which is notnbsp;very clear. Portions of it have been detached and cut in several directions to show the internal structure. Most of such characters abovenbsp;given are derived from this source. No. 12 is a very small piece, consisting entirely of the fibrous zone of wood, of which it shows the innernbsp;wall with the scars identical in character with those of No. 11, of whichnbsp;it is probably only a detached fragment. No. 17 is a crescent-shapednbsp;fragment from a small trunk, and weighs 2.27 kilograms. It appears tonbsp;have come from near the top of the trunk. No. 18 is a thin horizontalnbsp;zone or disk from near the top of a small trunk. The internal portionnbsp;is much crystallized.

The specimens on which this species are based, though clearly distinct in their external characters from any of the rest, are still so fragmentary and imperfect that in photographing the material they were overlooked, and no views were taken of . the outer surface. One ofnbsp;them, however. No. 11, has furnished an excellent section through thenbsp;armor and wood, an enlarged view of which is shown on PI. GXX.

1894. Cycadeoidea Jenneijaiia Ward: Proc. Biol. Soe. Washington, Vol. IX, April 9, 1894, p. 87.

Trunks large and tall, attaining a height of 130 cm., cylindrical, little compressed, 30 to 40 cm. in diameter, the girth reaching over a meternbsp;and a half, firmly silicified, more or less clialcedonized or opalizednbsp;within, very hard and heavy, light brown or reddish externally, whitenbsp;or reddish, sometimes black within; organs of the armor horizontal except near the summit; leaf scars arranged in intersecting spiral rows,nbsp;those passing from left to right making an angle of about 40� andnbsp;those from right to left of about 50� with the vertical axis; scarsnbsp;subrhombic to subtriangular with mostly rounded angles, sometimesnbsp;kite shaped, large, 20 to 30 mm. wide, 12 to 25 mm. high, partially ornbsp;wholly filled with the remains of the leaf stalks; vascular bundles in thenbsp;petioles arranged in an imperfect row all around near the margin withnbsp;other straight rows, or somewhat scattered in the interior, numerous (40nbsp;were counted in one cross section), circular, elliptical, crescent-shapednbsp;or kidney-shaped in section; ramentaceous inter.spaces very thick butnbsp;somewhat variable (0 to 13 mm.), sometimes roughened or irregularly

affected by small pits representiug bract scars, a line of wbicii may run tlirough the center, dividing tbe Avails, or by cracks Avliich dividenbsp;them into plates or small partitions; reproductive organs numerous,nbsp;large, and Avell developed, often protruding, sometimes cavitous, scattered over all parts of the surface, axillary to the leaf scars, Avhosenbsp;shape and order they distort, elliptical in outline, 25 to 40 mm. in anbsp;horizontal and 18 to 26 mm. in a vertical direction, surrounded bynbsp;concentrically arranged semilunar or somewhat triangular bract scars,nbsp;which are sometimes continued in a horizontal direction, converging andnbsp;blending Avith the roAvs dmding the Avails, the central portion, Avhennbsp;exposed at the margin of a fracture, taking the form of an elongatednbsp;cylindrical spadix or fruit, Avhich, seen in cross section, proves to benbsp;made up of four large organs that seem to contain two axes, andnbsp;seen in longitudinal section, to constitute a convex receptacle from whichnbsp;arise seminiferous peduncles (or filaments) and interseminal (or inter-staminate) scales, the seeds (or anthers) having disappeared, leaving anbsp;region of amorphous decayed tissue occupied by the matted prolongations of the chaff; armor 8 to 9 cm. thick; liber zone very indistinct;nbsp;cortical parenchyma 3 to 4cm. thick; fibrovascular zone about 2 cm.,nbsp;without visible subdivision into rings; medulla slightly elliptical, thenbsp;maijor diameter 16 to 17 cm., the minor 13 to 14 cm., black and cherty innbsp;all the specimens, showing no structure, giving off rays which ma3^ benbsp;seen traversing the woody cylinder.

The abovm description is based mainh' on two large trunks, or parts of the same trunk, Avhich, through the intervention of Professor Jenney,nbsp;were generously loaned to the Smithsonian Institution by Dr. Y. T.nbsp;M�Gillycuddj^, director of the State School of Mines of South Dakota atnbsp;Eapid Oily, where they had been deposited. There are manj' reasonsnbsp;for believing that these two pieces belong together, and Avith a smallnbsp;missing intermediary piece copstituted a tall, cylindrical trunk. One ofnbsp;the pieces, about 40 cm. long, represents the true base and the other, 58nbsp;cm. long, the true summit. The former is scarcely worn at all while thenbsp;latter is deeply eroded all round as the result of having been longnbsp;exposed to adverse influences, probably by having lain in the bottomnbsp;of a gulch. It is therefore considerably smaller than the normal diminution upward would require. The difference applies, however, Avholly tonbsp;the exterior, and the medulla and woody cylinder are no smaller thannbsp;would be the case in an entire trunk at different heights. After a careful examination I have arrived at the conclusion that if they are parts ofnbsp;one trunk it Avould only indicate the loss of about 30 cm., Avhich A\muldnbsp;give a total height for the trunk of about 130 cm.

Only two other tall, cylindrical species of Oycadeoidea are known to me, viz, the G. excels�, described below, and the C. gigantea of SeAvardnbsp;from the Purbeck beds of Portland.' Specifically, of course, G. Jen-neyana is very distinct from both of these, but in its straight, erect

' On Cycacleoidea gigantea, a new Cycadean stem from the Purheck heds of Portland, by A. C. Seward: Quart. Jour. Geol. Soc. London, Vol. LIU, February, 1897, pp. 22-39, pis. i-v.

habit it somewhat resembles C. gigantea. It is much less compressed laterally, aud if my conclusions are correct as to the amount missingnbsp;between the two sections, it was taller by 11 or 12 centimeters. Mr.nbsp;Seward does not state the weight of his specimen, but if the materialnbsp;at all resembles that of all other cycads from those quarries its speciticnbsp;gravity is low and the weight would be small in relation to the bulk.nbsp;He states the girth of the specimen at 107 cm, while that of C, Jen-neyana is very nearly 130 cm. More exactly, the lower piece measurednbsp;at the middle is 129.54 cm, while the upper jiiece, both at the lower endnbsp;and at the middle, measures 107 cm. The difference, as explainednbsp;above, is chiefly due to erosion of tlie surface of the latter. The lowernbsp;piece weighs 95.26 kilograms, and the upper 86.18 kilograms, a totalnbsp;of 181.44 kilograms. The entire trunk must therefore have weighednbsp;nearly 250 kilograms, which would give it the third rank, from thisnbsp;point of view, among the fossil cycads of the world.

The question whether there are any other specimens in the U. S. national Museum collection that belong to the same species is a morenbsp;difficult one. In 1893, as stated above (p. 562), an expedition was madenbsp;to the locality. Ho other fragments were found by any of our party,nbsp;although we all searched diligently for several hours and collected anbsp;large amount of silicifled wood. We were told at the ranch that anbsp;man named McBride {not Professor McBride, of course) had been innbsp;the region and had gathered and taken away all the specimens henbsp;could find.

Later in the summer, when I was in California, Professor Jenney learned the whereabouts of Mr. McBride, who was then in Deadwood,nbsp;and xiurcbased two fragments of cycads from him that he said camenbsp;from that locality. He also purchased two other fragments fromnbsp;Mr. L. W. Stillwell in Deadwood, which, as he was informed, came fromnbsp;the same jilace. All these he sent to Washington, and they constitutenbsp;a part of the cycad collection in my hands.

Upon careful examination of all four of these fragments I conclude that there is nothing to negative the supposition that three of themnbsp;belong to the same sjieoies as the large trunks, and I have accordinglynbsp;included them under Cycadeoidea Jenneyana. Tliey were numbered innbsp;the collection as McBride fragments Uos. 1 and 2 and Stillwell fragment Ho. 1.

These fragments are irregular and not well preserved, but they evidently came from large trunks, and all the characters that theynbsp;show agree substantially with those of this species. As they comenbsp;from the same locality and as a portion of the great trunk is missing,nbsp;I have examined them carefully to see whether they might iiossiblynbsp;belong to that trunk, but I find no evidence of this. These fragmentsnbsp;weigh, resjiectively, 12.25,11.34, and 7.26 kilograms.

A few days after visiting the locality on Black�s ranch I was in Hot Springs, and purchased a number of fragments of cycads from a dealernbsp;named Homer Moore. Two of these which fitted together, forming a

block weigliing� a little more than 7 kilograms, evidently belonged to a very large trunk, and these show a number of characters which agreenbsp;with those of G. Jenneyana. In fact they very closely resemble thenbsp;Stillwell fragment No. 1, so that whatever is done with the one mustnbsp;be done also with the other. Mr. Moore thought that these specimensnbsp;came from the Minnekahta region, but was uncertain as to their source.nbsp;They certainly differ specifically from any of the material from thatnbsp;region and agree substantially with most of that from Black�s ranch,nbsp;I shall therefore include them under 0. Jenneyana.

1 had in hand two small slabs belonging to the Woman�s College of Baltimore, purchased by Mr. Arthur Bibbins for that college at thenbsp;World�s Columbian Exposition in Chicago and sent over along with thenbsp;Bibbins collection from Maryland. Mr. Bibbins was informed when henbsp;purchased these fragments that they came from the Black Hills innbsp;America and that they were cnt and polished in Germany. I can wellnbsp;believe this, as, so far as they go, they are substantially identical withnbsp;the material from Black�s ranch, and I am obliged to refer them to thenbsp;present species. They contain none of the woody cylinder but are confined to the armor, of which they show a thickness of 3 to 5 cm. Thenbsp;exterior is obscure and closely resembles the Stillwell fragment No. 1,nbsp;and the Homer Moore fragment, but the inner face is cut in a directionnbsp;transverse to the leaf bases, which are bea.utifully shown, and alsonbsp;in the opposite direction showing the organs in longitudinal section.nbsp;Fruiting axes are thus exposed, and much of the above descrijitionnbsp;relating to the structure of these organs is derived from a study ofnbsp;these sections. I have no doubt that the other specimens when similarly cut, as they will be eventually, will furnish the same characters.nbsp;In fact, they can now be indistinctly seen on a number of fracturednbsp;surfaces.

These specimens bear the labels of the museum of the Woman�s College, Nos. 1501 and 2128. The former weighs 532 grams and thenbsp;latter 489 grams. They are exactly alike in all essential respects, andnbsp;may well have belonged to the same trunk.

In the Yale collection there are 24 specimens that appear to belong to this species. These are Nos. 81, -87, 88, 90, 91, 93, 96, 97, 98, 101,nbsp;102, 108, 109, 111, 112, 113, 114, 115, 116, 120, 121, 124, 125, and 126.nbsp;It M'ill be observed that all but the first two of these came with thenbsp;last two invoices and are from the Blackhawk region, the same tromnbsp;which the original type of the State School of Mines was obtained.nbsp;The two reported from the Minnekahta region. Nos. 81 and 87, alsonbsp;belong to this species beyond a doubt. No. 81 consists of eight smallnbsp;fragments which all fit together and form an irregular segment from anbsp;large trunk similar to those belonging to the State School of Mines ofnbsp;South Dakota. Indeed, they might have belonged to the supposednbsp;missing jiortion of the tall trunk which those two pieces are believednbsp;to have so nearly constituted (see PI. CXXV). The eight fragmentsnbsp;together weigh 9.5 kilograms.

i^o. 87 also consists of a number (five) of small fragments that can be built up into a segment of a trunk, and all together weigh 7.G kilograms; but these do not so closely resemble the type specimens. Stillnbsp;the characters they possess are those of this species. Professor Marshnbsp;thought that these specimens came from the Blackhawk locality, butnbsp;Mr. Stillwell, from whom they were purchased, states that they werenbsp;obtained 3 miles southwest of Minnekahta station. This agreesnbsp;closely with the original locality. I am disposed to believe that therenbsp;has been some mistake, and that these particular specimens are, afternbsp;all, from the Blackhawk region.

Of the other 22 from the Blackhawk region �Tos. 91, 113,120, and 124 are somewhat doubtful. No. 91 has a large terminal bud 8 cm. high,nbsp;elliptical in cross section and 15 by 20 cm, in diameter, studded withnbsp;polygonal bract scars 5 to 8 mm. in diameter, filled with the bases of thenbsp;bracts or small leaves matted together and exposed on the sides of thenbsp;terminal bud, which have suffered from erosion (see PI. CXXXl). Inbsp;have not included this bud in the description of the species on accountnbsp;of doubts as to the true affinities of this specimen, which, if it belongsnbsp;here, is the only one in which the bud is preserved. The surface is sonbsp;badly worn that all the reliable characters are obscured, except that innbsp;geiveral shape the specimen agrees with others of this species. Thenbsp;scars are large and the walls thick, which further confirm this supposition. No. 113 is also badly worn and metamorphosed, but probablynbsp;belongs to this species. It is a tine trunk, nearly comxdete, 55 cm.nbsp;high, and weighs 91.17 kilograms. No. 120 is an interesting specimen,nbsp;and shows a great number of large fruits, which stand out, havingnbsp;resisted the deep erosion of the surface (see PI. CXXXII). No. 124 isnbsp;a mass of quartz and only a fragment, but in all probability came fromnbsp;a trunk of G. Jenneyana.

The rest of the siiecimens, though mostly fragments and segments from large trunks, are not doubtful, as they show surface characters innbsp;all cases which are distinctive. Several, however, are tine trunks.nbsp;No. 101, though in three sections perfectly fitting together, is an almostnbsp;comxilete trunky laterally compressed, 97 cm. high, and weighs 183.71nbsp;kilograms, which is a little more than 1 kilogram heavier than bothnbsp;pieces of the type specimen from the State School of Mines of Southnbsp;Dakota. Unfortunately the surface is badly worn and the most iirqior-tant characters are obscured. No. 102 is the lower part (3G cm.) ofnbsp;the largest trunk of the species thus far known. It is nearly circularnbsp;in cross section, has a diameter of 47 cm., and a girth of 15G cm. Its surface is also in a fair state of preservation (see Pis. OXXVII-CXXIX).nbsp;No. 121 is a similar but much smaller basal portion. No. 115 is anomalous in many respects and might have been included among the doubtfulnbsp;cases. Though in two xjieces it is nearly comxgt;lete and weighs 87.77nbsp;kilograms, having a height of GO cm. and a girth of 106 cm. Somenbsp;of the leaf bases are horizontal, while others are strongly declined.nbsp;The latter are all on one side below the middle, and in the case of

certain abnormally small but strongly projecting leaf bases there is the additional peculiarity that they are converted into impure opal ornbsp;bln� quartz (see PI. CXXX). Xo. 116 is also a fine, nearly completenbsp;trunk 49 cm. high, 42 by 36 cm. in diameter, 120 cm. in girth, and weighsnbsp;85.73 kilograms.

Pis. OXXT-OXXV illustrate the great trunks from the State School of Mines of South Dakota. Pis. CXXI and CXXII show the external surface of both trunks on the two opposite sides. PI. OXXIII shows thenbsp;true base and true summit, the latter somewhat decayed, forming anbsp;depression or �crow�s nest.� PI. OXXIV gives a view �f the two endsnbsp;that would have matched each other had nothing been lost. In PI.nbsp;CXXV tlie two segments are placed as nearly as jmssible in the position in which they stood when livnng, with an esti mated interval betweennbsp;them for the portions lost.

PI. OXXVI represents the polished surface of Xo, 1501 of the Museum of the Woman�s College of Baltimore and shows the characters abovenbsp;described for that specimen.

Pis. OXXVII-GXXXII represent the specimens of the Yale collection, Xos. 91, 102, 115, and 120, as mentioned above and as fully explained in the descriptions of the plates.

It will be seen from the above that 32 specimens have been referred to this species. Of these, 27, including all the larger trunks, were foundnbsp;with certainty in the Blackhawk region. Two were reported from thenbsp;Minnekahta region and probably came from thei'e. The source of thenbsp;other three is uncertain.

Trunks large or colossal, ellipsoidal in form, thickest at the middle part, diminishing and more or less rounded off at both base and summit, slightly elliptical or nearly circular in cross section, unbranchednbsp;or with a few small secondary axes in the form of protuberances, usually of a dark color, hard consistency, and liigh specific gravity, attaining a maximum height of 85 cm., girth of 170 cm., and weight of overnbsp;300 kilograms; organs of the armor slightly declined near the base,nbsp;horizontal in the middle portion, ascending above, and erect at thenbsp;apex, producing a large terminal bud consisting of the bases of somewhat flattened leaf-like bracts or scales; leaf scars arranged in twonbsp;sets of rows passing spirally round the trunk, intersecting each other,nbsp;and forming each a different angle with the axis, those passing fromnbsp;left to right forming an angle of about 35� to 45�, while those passingnbsp;from right to left form an angle of 50� to 60�; scars large, 35 to 50 mm.nbsp;wide, 20 to 35 mm. higli, peculiar in shape, the lateral angles drawn outnbsp;into sharp points by the incurving of the sides, the vertical consistingnbsp;of mere curves, varying from this to simple gibbosity; leaf bases always

present, filling tbe scars and often projecting, presenting either plane or slightly convex surfaces; vascular bundles in one row closely setnbsp;together and very near the margin, and an irregular ring at the centernbsp;inclosing an empty space; ramentaceous interspaces thin, 3 to 10 mm.,nbsp;scaly or laminated, sunk below the leaf bases, forming grooves on thenbsp;surfaces of the trunk, often white in color, contrasting with other iiarts;nbsp;reproductive organs abundant, especially in the upper part of thenbsp;trunks, very different from the leaf bases, nsually large, elliptical, 5 tonbsp;6 cm. wide by 3 to 4 cm. high, sometimes solid and projecting, but usuallynbsp;with an opening at the top or cavitons and crater-like, surrounded bynbsp;numerous bract scars filled with the bases of the bracts, which arc usually narrowly triangular or nearly flat; armor 5 to 10 cm. thick, more ornbsp;less clearly marked off' from the underlying tissues; cortical parenchymanbsp;3 to 4 cm. thick; zone of secondary wood 4 cm.; medulla 10 to 20 cm. innbsp;diameter.

A perfectly well characterized species differing entirely from any of those based on specimens from the Minnekahta region. It is also verynbsp;distinct from G. Jenneyana, which is the leading form of the Blackhawknbsp;region. Still, this species is also common there, and is represented innbsp;the collection by eight specimens, viz. Nos. 92, 94, 99, 100, 103, 117,nbsp;122, and 123. No. 100 is taken as the type and is the next largestnbsp;cycadean trunk known in the world, weighing 303.91 kilograms. Itnbsp;slightly exceeds in height the IT. S. National Museum type of G. colos-salis, having a maximum length of 85 cm. Its diameters are respectively 62 cm. and 49 cm., and it has a girth of 170 cm. But, like allnbsp;other specimens of this species, it diminishes in size toward eachnbsp;end and is somewhat barrel-shaped. Nos. 103 (see PI. OXXXVI^nbsp;CXXXVII) and 117 (see PI. CXXXVIII, CXXXIX) represent thenbsp;lower part of two other large trunks, and the summit is representednbsp;only in No. 100. No. 94 (see PI. CXL, GXLI) comes next in iioint ofnbsp;interest in affording most of our knowledge of the internal structure ofnbsp;the species, including the markings on the medulla. No. 123 (see PI.nbsp;CXLII, CXLIli; is also instructive from this point of view. The restnbsp;are fragments, but all add to the complete conception of the species.

The form of the leaf scars is imitated very closely by two other species, one of which, G.formosa, is represented by'only one specimen,nbsp;No. 89. The other is G. Stillwelli, and this is made very clear by thenbsp;new material added by the specimens last sent from the Blackhawknbsp;region by Mr. Wells, especially No. 105. In both these cases, however,nbsp;the scars are much smaller, and this is particularly the case with G.nbsp;Stillivelli.

The species is illustrated by Pis. OXXXIII-CXLIII, which have been commented upon in the foregoing remarks and are further fullynbsp;explained in tbe descriptions of the plates.

Trunks of moderate size, short-conical, unbrauched, dark brown, nearly black within, of average specific gravity, about 25 cm. high,nbsp;nearly 30 cm. iu diameter aud having a girth of somewhat less than anbsp;meter; organs of the armor, even the lowest, somewhat ascending yithnbsp;a uniform angle; leaf scars arranged in two series of spiral rows, thosenbsp;of both series making an angle with the axis of about 50�; scars largenbsp;for the size of the trunk, peculiar in shape, the lateral angles verynbsp;sharp, the vertical ones very obtuse and rounded, the bounding sidesnbsp;usually curving downward and upward on the right and left, causingnbsp;the scars to be drawn out laterally corresponding to wings of thenbsp;petioles, lower side more pronounced than the upper in such a mannernbsp;that a line joining the lateral angles divides the scar into unequal areas,nbsp;varying to simply gibbous by the absence of the above-described curvms;nbsp;distance between lateral angles 25 to 30 mm., that between highestnbsp;and lowest points 10 to 20 mm.; leaf bases always present, usuallynbsp;projecting somewhat, sometimes nearly 1 cm., outlines definite, conforming to shape of scars, exposed ends presenting surfaces that are exactlynbsp;square or tangential to the trunk, never convex nor concave, smoothnbsp;but not polished, covered by a diaphragm representing a natural planenbsp;of disarticulation, this layer, however, sometimes removed, in whichnbsp;case small projecting points are irregularly scattered over the surfacenbsp;of the leaf base; outer row of leaf bundles very close to the margin,nbsp;faintly visible at the ends, more clearly as striae on the eroded sidesnbsp;of projecting leaf bases; ramentum walls thin, 1 to 3 mm., thickeningnbsp;at the angles, sunk below the petioles and usually separated from themnbsp;by a crack, dull colored, loose in structure and somewhat pitted, havingnbsp;the appearance of cracks filled with mud or extraneous matter; reproductive organs numerous and well marked, occurring at all points, butnbsp;tending to an arrangement in vertical rows, one above another, with anbsp;trend difierent from that of either of the rows of leaf scars, projectingnbsp;beyond the leaf bases to which they bear no resemblance, rounded ornbsp;elliptical, 3 to 0 cm. in diameter, never cavitous, usually exhibitingnbsp;concentrically arranged scars, the circular central portion inclosed innbsp;a tube surrounded by iuvolucral bract scars occupied by the bases ofnbsp;the bracts which project in miniature imitation of the leaf bases, thenbsp;central portion sometimes occupied by small cylindrical bodies or rodsnbsp;1 mm. in diameter and 1 to 5 mm. long, consisting of nearly pure quartz;nbsp;armor 5 cm. thick, definitely separated from the axis by a porous libernbsp;zone of appreciable thickness; cortical parenchyma 15 mm. thick;nbsp;secondary wood 4 cm. thick, consisting of two distinct rings of aboutnbsp;equal thickness separated by a peculiar scalloped line, apiiarentlynbsp;caused by the convex edges of woody wedges, 5 mm. thick, separatednbsp;by thin medullary rays; medulla 9 cm. in diameter, somewhat heterogeneous or chambered in structure.

This species is represented by the single specimen ^To. 89 of the Tale collection. It has close affinities on the one hand with G. ingens andnbsp;on the other with C. StillwelU, while all the.se are related to 0. MoBridei,nbsp;but it is impossible to refer it to any of these species.

PI. OXLIV shows the side of the trunk with the peculiar shaped scars and two of the vertical rows of fruiting organs. PI. CXLVnbsp;shows the remarkable smooth base with its concentric structure. PLnbsp;CXLVI is a view of the top where the thickness of the armor andnbsp;other features appear to advantage.

Trunks small, cylindrical, or more or less laterally compressed, 30 to 40 cm. high, 15 to 25 cm. in diameter, 40 to 70 cm. in girth, reddish ornbsp;light colored externally, cherty, flinty, or more or less agatized within,nbsp;simple, or bearing a few small branches in the form of projections ornbsp;protuberances, sliort-conical at the summit, with a natural depressionnbsp;at the apex studded with small polygonal scars and a gentle swellingnbsp;at the center; organsof the armor nearly horizontal; leaf scars arrangednbsp;in two series of spiral rows, those from left to right making an angle ofnbsp;40� to 50�, those from right to left of 30� to 50� with the axis of thenbsp;trunk; leaf scars normally almost exactly rhombic or diamond-shaped,nbsp;but with a tendency on the one hand to the rounding of the verticalnbsp;angles and on the other to the incurving of the sides so as to exaggerate the acuteness of the lateral ones, this sometimes very marked;nbsp;scars small, 20 to 25 mm. wide, 15 to 20 mm. high, occasionally almostnbsp;as high as wide, the lateral diagonals about horizontal and the verticalnbsp;ones perpendicular to them or vertical; leaf bases always present,nbsp;filling the scars, often projecting, sometimes considerably, the petiolesnbsp;disarticulating at several different points by means of a diaphragmnbsp;which forms a thin layer over the exposed summits, the occasionalnbsp;absence of which leaves a rough, spongy or porous structure; vascularnbsp;bundles arranged in two rows, one near the margin and parallel tonbsp;it, the other forming an elliptical ring at the center 3 by 4 mm. innbsp;diameter, both rows usually appearing in the form of denticulate ridges;nbsp;ramentaceous walls very thin, 1 to 2 mm., often sharp at the surface,nbsp;generally sunk below the leaf bases, forming grooves or deep channelsnbsp;between them, the surface therefore consisting chiefly of the latter, innbsp;the more abnormal forms of scar describing a double curvature andnbsp;having somewhat the shape of a �line of beauty� in penmanship ornbsp;one of the parts of a Buddhist cross or �swastika,� sometimes, however, projecting so as to leave a groove around the outer edge of thenbsp;convex summits of the leaf bases; reproductive organs few, morenbsp;numerous on the narrower sides of the trunk, disposed somewhat innbsp;rows or chains, generally parallel to the axis but sometimes running

round tlie trunk, more or less contiguous, consisting of protuberances, some rising above tbe highest leaf bases, closed, or more commonlynbsp;open at the top, sometimes crater-like but generally truncated, i)re-senting an irregular surface with numerous pits or pores at the centernbsp;surrounded by bract scars which are sometimes empty, but usuallynbsp;occupied by the bases of narrowly triangular or flattish bracts projecting and squarely truncated with thin interspaces in miniature imitationnbsp;of the leaf bases; armor much thicker on the narrower than on thenbsp;broader sides of the trunk, 3 to G cm. thick iii the former and 3 to 3 cm.nbsp;in the latter case, clearly and definitely marked off from the woodynbsp;axis by a cambium line; cortical parenchyma 15 to 20 mm. thick; secondary wood zone 10 to 30 mm., very fine grained and clearly markednbsp;off from the last; medulla somewhat elliptical, 5 to 8 cm. in diameter,nbsp;marked on its extenial surface by rows of small rhombic projections ofnbsp;a dark color terminating small longitudinal ridges repre-senting thenbsp;origin of the medullary rays.

The small cylindrical section of a trunk acquired through Professor Jenney�s intervention from Mr. L. W. Stillwell, of Ileadwood, exhibitednbsp;so many good characters, all different from those of any other specimennbsp;in the U. S. National Museum collection, that before I had seen the Yalenbsp;collection�in fact, long before it was made�I had described it as a newnbsp;species and named it for Mr. Stillwell. It was reiiorted to have beennbsp;found in the Blackhawk region, and there is every reason to believe thatnbsp;such was the case.

The Yale collection contains six specimens of this species, each of which adds something to our knowledge of it. These are Nos. 16,36,56,nbsp;105,107, and 119. The first three of these j)urport to come from thenbsp;Minnekahta region, while the others are certainly from the Blackhawknbsp;region. The first of these is somewhat smaller than the type and hasnbsp;near its summit two small branches. The leaf scars are normal andnbsp;confirm my suspicion that the peculiar form which they have in thenbsp;original specimen is due to lateral compression. It weighs nearly 5nbsp;kilograms. No. 36 represents the upper part of a trunk of exactly thenbsp;same diameter as the Stillwell specimen,but with theouter parts all wornnbsp;away. The summit, however, is perfect. The transverse fracture hasnbsp;supplied a number of otherwise jnissing or imperfect characters. Thisnbsp;specimen weighs 8.17 kilograms. No. 56 is larger and entire from basenbsp;to summit, but broken in two near the middle. It is very elliptical innbsp;cross section from lateral compression, badly worn like the others, andnbsp;has a slab scaled off� from one side, exposing the outer surface of thenbsp;medulla and corresponding inner wall of the woody zone. This specimen is 39 cm. high, 15 by 20 cm. in diameter, and has a girth of 54 cm.nbsp;Its ellipticity is, however, exaggerated by the greater erosion of thenbsp;flat sides. It weighs 12.7 kilograms.

No. 105 is only a section weighing 12.8 kilograms, with base and summit wanting, also a piece from one side, part of which was saved.

but the part that remains shows the outer surface in the most perfect state of preservation, and much of the above description of the phyl-Jotaxy, leaf scars, petioles, vascular bundles, raineutum walls, etc., is 'nbsp;derived from it. No. 107 is also an exceedingly interesting specimen,nbsp;weighing 9.07 kilograms, and is especially valuable as showing the truenbsp;base. It is obliquely broken through from the top to near the bottom,nbsp;but one side shows the spiral rows of leaf scars. No. 119, althoughnbsp;larger, weighing 14.29 kilograms, is not as well preserved, but alsonbsp;shows the base, which is slightly concave.

Upon the whole, this species may be regarded as one of the best characterized of all that have been based on cycadeau trunks alone.

PI. OXLVII shows the best side of the original Stillwell type with its peculiar scars. PI. CXLVIIl gives views of No. 36 of the Yale collectionnbsp;seen from its best side (Fig. 1) and from the transverse fracture (Pig. 2).nbsp;In the latter the ring of exogenous tissue can be distinctly seen. PI.nbsp;CXLIX shows trunk No. 56 of the Yale collection to good advantage,nbsp;including the exposed medulla. The small piece on the lower left titsnbsp;into the upper part of the fracture. It is here turned round so as tonbsp;exhibit the counterpart of the medulla as impressed on the inner wallnbsp;of the woody zone. PI. CL shows at Fig. 1 the most perfect sidenbsp;of No. 105, the regularity of whose scars is scarcely exceeded by anynbsp;known cycadean trunk. Pig. 2 of the same plate shows the side opposite, on which the leaf bases project to unequal distances above thenbsp;surface. PI. CXLI gives two views of No. 107, the peculiar shape ofnbsp;which is described above. Pig. 1 represents the narrow portion betweennbsp;the oblique even base and the plane fractured surface parallel with it.nbsp;It is over this area that the arrangement of the scars is most definite.nbsp;Pig. 2 is a good view of the base, but also takes in the broadest side ofnbsp;the inclined trunk above. PI. CLII shows a side (Fig. 1) and a basenbsp;(Fig. 2) view of No. 119. The latter is perhaps the best exposure of thenbsp;base that we have.

Trunks tall, compressed-cylindrical (only specimen known 91 cm. high and truncated) with an enlarged base, 112 cm. in circumference at thenbsp;base, 80 to 90 cm. at all other points, light ash colored without, whitishnbsp;or bluish within, soft externally, fine-grained inside and moderatelynbsp;hard, with the specific gravity rather low, unbranched but more or lessnbsp;irregular, crooked, zigzag, and inclined; organs of the armor horizontal, or at right angles to the axis; leaf scars disposed in two series ofnbsp;spiral intersecting rows, those from left to right making an angle ofnbsp;20�, those from right to left of 50� with the axis; scars imperfectlynbsp;rhombic or rectangular, the diagonals 16 to 25 mm., the lateral anglesnbsp;nearly alike, the vertical ones usually unlike, the ui)per consisting of a

deep but obtuse sinus, the lower also obtuse but relatively shallow, sometimes reduced to a gentle concave curve formed by the two lowernbsp;sides; leaf bases generally preserved to within 2 cm. of the surface, disarticulated at a natural joint, their surfaces even and concave but roughened and affected by many small dots of a dark color, irregularlynbsp;arranged, perhaps representing gum ducts, and some large pits whichnbsp;may have contained leaf bundles; ramentaeeous walls thin and frail, 1nbsp;to 2 mm., of a light color within, contrasting with the darker leaf bases,nbsp;thickened at the angles and more or less compound, with a few smallnbsp;pits representing soars of bracts or iierulae; reproductive organs numerous, usually solid, harder than the remaining parts, hence often projecting from the eroded surfaces, of different sizes, the smaller ones probably abortive and occupying angular spaces among the leaves, the wallsnbsp;dividing and surrounding them, circular in section, with or withoutnbsp;bract scars, the larger ones lying in interrupted rows running in thenbsp;same direction as those of the scars which they crowd and distort,nbsp;elliptical in section, the longer diameter being along the line of thenbsp;rows, 25 by 38 mm. in diameter, usually solid excex)t their roughenednbsp;extremities, sometimes open or crater-like at the summit, a few solidnbsp;and cylindrical (one of which has been detached and will be sliced fornbsp;microscoiiic sections); armor 4 to 7 cm. thick, separated from the axisnbsp;by an even line; xgt;arenchymatous zone 2 cm. thick; fibrous zone 3 cm.,nbsp;divided into three rings, one of which exhibits in places a somewhatnbsp;open structure, crossed by thin medullary rays and inclosed betweennbsp;walls or sheaths of harder material; medulla 13 cm. in diameter andnbsp;nearly circular, solid, fine grained, and homogeneous in structure.

The fine specimen ujion which the above description is wholly based was purchased by me from Mr. Homer Moore, at Hot Springs, Southnbsp;Dakota, on August 22, 1895, together with the two fragments abovenbsp;described belonging to 0. Jenneyana. It consists of four jneces whichnbsp;belong together and form a very remarkable trunk, differing greatlynbsp;from any other from the Black Hills or from any other section.

I inquired carefully into the history of these specimens and learned that some years before they had been found by a railroad employeenbsp;named A. B. Noble, who was no longer in that region, some 2 milesnbsp;below Hot Springs in a canyon or ravine which makes into Fall Kivernbsp;from the northeast. No further details could be gathered, but as it is 4nbsp;miles to Evans quarry, where the true Dakota groux) is exxiosed, it isnbsp;certain that the horizon must be in the Lower Cretaceous, and it isnbsp;Xirobably substantially the same as that of all the other trunks.

The four pieces or sections which have been numbered from 1 to 4, beginning with the basal one, maybe briefly described as follows:

No. 1, which is considerably the largest in all respects, represents the true base and swells out below to a diameter of over 40 cm. and a girthnbsp;of nearly 112 cm. It is slightly elliptical, the minor axis of a crossnbsp;section being only 33 cm., but xgt;art of this difference is due to the erosionnbsp;of the armor on the broader sides.

jSTo. 2 is a, shorter and smaller piece, but fits perfectly upon the upper fracture of iSl o. 1, which is somewhat oblique. On one side a large elliptical area has decayed, forming a depression which reaches to the bottom of the leafstalks. This depression is about equally divided betweennbsp;Nos. 1 and 2.

No. 3 is a much shorter piece, the upper fracture of which is very oblique, so as to make it almost wedge shaped. The upper surface ofnbsp;No. 2 and the lower surface of No. 3 do not form a perfect joint. A thinnbsp;slice or a number of such pieces have apparently scaled off and arenbsp;wanting. There is, however, abundant evidence of the general agreement of the two sections, and one decayed area extends across the breaknbsp;and reappears on No. 3.

No. 4, which is the uppermost section, fits perfectly upon No. 3. The fracture across the top is oblique in the opposite direction from that ofnbsp;the lower end, thus increasing the cuneiformity of both sections. Whennbsp;superposed upon each other these two upper sections form a sort ofnbsp;crook or bend in the trunk, so that the center of gravity falls considerably on one side and the upper piece falls off unless supported.

The trunk has evidently long lain on one side or the other as determined by the above-mentioned crook or bend and been subject to much erosion on the two exposed sides, while the other two sides have correspondingly escaped. The result is that the leaf scars are deeply wornnbsp;over much of the surface, while along the protected sides they are preserved or only irregularly broken down, leaving what look like jaggednbsp;projections.

No. 1...................................................................... 50. 80

No. 2...................................................................... 21.32

No. 3...................................................................... 17.02

No. 4...................................................................... 18. 37

This species is illustrated by three jilates. One side of the specimen is better preserved than the other, and 1 have given views of both onnbsp;PI. CLIII and CLIV, the first of which shows the trunk leaning tonbsp;the left and the second to the right. PI. OLY affords a good view ofnbsp;the base.

Trunks very small, symmetrical, short-conical, laterally subcompressed, 12 cm. high, 15 by 17 cm. in diameter, 49 cm. in girth, dark colored, well silicified, of medium hardness and specific gravity,nbsp;unbranched, summit not depressed, terminal bud projecting from apex;

leaf bases ascending, even tbe lowest ones, scars arranged in two series of spiral rows, those from left to right making an angle of 80� andnbsp;those from right to left of 50� with the axis, very small, subrhombic,nbsp;averaging 10 mm. wide by 6 mm. high, smaller near the summit, emjitynbsp;to considerable depth; ramentaceous interstices 1 to 3 mm. thick, firmnbsp;in texture, usually consisting of three layers, which may be regardednbsp;as a lining to each of the adjacent scars, with a thicker membranenbsp;between; reproductive organs few, poorly defined, slightly projecting,nbsp;with irregular markings on their outer surfaces, probably for the mostnbsp;part immature or abortive; armor 3 to 5 cm. thick; axis 8 cm. in diameter, somewhat clearly marked off from the armor but without clearnbsp;boundaries between the cortical parenchyma and fibrous zone ornbsp;between the latter and the medulla, so far as the single known specimen shows without cutting.

This species differs from all others in a number of characters besides its small size.

The only specimen is No. 81 of the Yale collection, a small, almost perfect trunk, weighing only 2.95 kilograms. At first glance it recallednbsp;the G. pygmcva of England, from the Lias of Lyme Eegis, figured bynbsp;Lindley and Hutton in the Fossil Flora of Great Britain, Vol. II,nbsp;pi. cxliii, but on confronting the specimen with that figure the differences are obvious. Except for its small size it might be compared tonbsp;C. marylandica, from the iron-ore clays of Maryland, and of all thenbsp;specimens of that species it most resembles the fragment which Professor Fontaine designated as No. 2,* and which I have described asnbsp;Johns Hopkins Cycads, No. 3.� That specimen, however, has a largenbsp;secondary axis, which, with better material, might take it out of thatnbsp;species.

Of all the forms from the Black Hills, it most resembles in the character of the scars, etc., some of the smaller branches of C. Marshiana, in which these are considerably reduced in size. I have therefore had anbsp;faint suspicion, which I would not leave the subject without expressing,nbsp;that it might be one of these secondary axes or knots, as it were,nbsp;wrenched from the larger trunk and found in an isolated position.nbsp;With this thought in mj^ mind I have examined a great many suchnbsp;cases, but I can find none in which the fracture at the point of separation at all resembled the base of this specimen, they all showing thenbsp;break to have been due to some extraneous cause, whereas the base ofnbsp;this specimen is perfectly natural, not torn nor cracked, and shows thenbsp;medulla at the center. Nevertheless, thei�e is something a little anomalous in the way the armor surrounds the axis.

The specimen is nearly uniform on all sides, as shown by the two figures of PL CLVI, which afford side views of two of the sides.nbsp;PI. CLVII is a view of the base, which shows no depression, but simply

�Potomac or Tonnger Tvlesozoic Plora. Monogr.TJ. S. Gcol. Surv., Vol. XV, 1890, p. 192.

a couvex surface with the medulla near the center, and elongated leaf scars ascending in all directions from it.

The above arrangement of the species of Gycadeoidea from the Black Hills is not wholly without method. It is true that there is no linealnbsp;arrangement that can be regarded as satisfactory, and yet tliere arenbsp;decided affinities among the species. These affinities, however, arenbsp;shown in particular characters, and the same species may have somenbsp;characters almost in common with two or more other species that arenbsp;otherwise very different. This is specially the case with branchingnbsp;species in which other characters resemble those of unbranched species.nbsp;For example, C. turrita^ except in its branching habit, is closely alliednbsp;to G. McBridei, which never branches; G. Ilarshiana, but for its branching, would be nearly related to G. colossalis; and G. Wellsii may benbsp;almost regarded as an unbranched form of G. minnekahtensis.

In view of these and many other more subtle peculiarities, I have sought, since the arrangement must be lineal, to compromise in such anbsp;manner as to bring those species most akin as near together as possible,nbsp;but it is clear that any arrangement would widely separate species thatnbsp;are similar in one respect or another.

C. dacotensis and G. colossalis are obviously very closely allied species. C. Wellsii can scarcely be said to form a transition from C. colossalis tonbsp;G. minnekahtensis, but it resembles the former at least in the one fact ofnbsp;being simple. C. pulcherrima is somewhat close to G. minnekahtensis.nbsp;C. cicatricula can not be said to form a transition from C. pulcherrima tonbsp;G. turrita, but it has considerable affinity to the former. C. turrita isnbsp;related to G. minnekahtensis and G. pulcherrima, and from it to C.nbsp;McBridei, as already remarked, the distance would be very small butnbsp;for the branching habit of the former.

Between G. McBridei and C, Marshiana, however, there is scarcely any bond, and it might have been as well to place the latter immediately after G. colossalis. We virtually begin a new series here and passnbsp;naturally through 0. furcata to G. Colei and G. Paijnei. �. Wielandinbsp;has so much affinity to G. Paynei that it was first placed in that species.nbsp;G. aspera also closely resembles G. Paynei in external aspect, but thenbsp;two anomalous characters noted clearly distinguish it from all others.nbsp;It fits in here, however, and G. insolita and G. occidentalis belong to thisnbsp;same general group.

G. Jenneyana, G. ingens, G.formosa, G. Siillwelli, and G. excelsa may also be said to form a group. The first and the last two constitute thenbsp;only cylindrical forms known in America. The shape of the scars innbsp;C. ingens, G. formosa, and G. Stillwelli unite these three from thatnbsp;important point of view, while those of G. Jenneyana and 0. ingensnbsp;tend to approach each other. G. excelsa has little in common with anynbsp;other species, and C. nana almost nothing. These two are thereforenbsp;properly made to close the series.

Ill the historical introduction to this paper (p. 529), and again in the chapter on the Minuekalita region (p. 552), the remarkable fossilnbsp;forests of that section of the Black Hills were unavoidably discussed.nbsp;In the chapter on the Blackhawk region (p. 502) the occurrence ofnbsp;silicified wood in great abundance was noted. Professor elenney, innbsp;his very full treatment of the Hay Creek region, lays jiroper stress onnbsp;the great quantities of fossil wood at many of the localities and horizons where he worked. It is much to be regretted that this importantnbsp;department of the present section on the Flora of the Black Hills couldnbsp;not have received full treatment. This deficiency is not due to anynbsp;lack of material for such a treatment, but almost wholly to the specialnbsp;difficulties attending the elaboration of this class of material. A. goodnbsp;collection was made from the original forest, some of the specimensnbsp;being broken from tjie great fossil log described, others picked upnbsp;among the branches. A short distance northwest of this spot woodnbsp;was also very abundant, and many specimens were taken. This woodnbsp;usually has the outward appearance of showing the internal structurenbsp;well, and two of the most promising specimens were cut and microscopic slides mounted for determination; but when these were examinednbsp;by Hr. F. H. Kimwlton with the compound microscope they were foundnbsp;to be too obscure to show any characters. It is evident that a largenbsp;number of specimens will have to be examined before one is foundnbsp;that will yield the desired results. This there has not been time to do,nbsp;and Dr. Knowltou has been too much occupied with other pressingnbsp;work to undertake such a systematic study of this material as will benbsp;necessary to test its value.

A line collection of silicified wood was made from the Blackhawk region, partly from the particular spot where Mr. Getchell told us thenbsp;cycad trunks lay and partly from the general vicinity, particularly fromnbsp;a locality half a mile east of the ranch house. As showing how deceptive a microscopic examination of such material often is, I may addnbsp;that by far the finest looking specimen found in this region, in whichnbsp;the grains of the wood are seen with great distinctness, was cut in allnbsp;necessary directions and slides were made from it, in full confidence thatnbsp;they would clearly indicate the nature of the timber of that region innbsp;Lower Cretaceous time, but to our great disappointment no detailednbsp;structure was revealed.

Professor Jenuey collected a considerable amount of fossil wood at a number of horizons iu the Hay Creek region, but none of it lookednbsp;promising, and after so many failures with much better appearingnbsp;material it was not thought worth while to attempt its study, althoughnbsp;it is quite possible that some of it may prove much better than it looks.

While our party were gathering up the fragments of cycads on the slope where so many fine trunks were found, a peculiar block attracted

tlie attention of Mrs. Jenney, who brought it to my notice. I first thought it might be the internal portion of a cycadean trunk, but uponnbsp;examination I was convinced that it was a piece of silicifled wood. Itnbsp;was thrown into the wagon with the rest and shipped to Washington.nbsp;�To other fossil wood was seen by me at the cycad locality. Coming asnbsp;it did from the very same spot as the cycads, its importance was greatlynbsp;increased, and at my request Dr. Knowlton took it np, marked it fornbsp;sectioning, and had some slides made. To our great delight it wasnbsp;found to be in an admirable state of preservation and perfectly determinable. It belongs to the genus Araucarioxylon�i. e., it is the ancientnbsp;representative of the Araucarian pines of the Southern Hemisphere,nbsp;which have long since disappeared from all our Western forests.

Dr. Knowlton furnished me a brief report upon this species for my eai'ly iiaper, and, although he has now described and figured it thoroughly, it will be of interest to reproduce his original and less technicalnbsp;account of it as follows:

The structure of this wood is very finely preserved, and a glance suffices to show that it possesses the Araucarian type and represents, with little question, an undescribed species of the genus Araucarioxylon. The wood cells are provided with twonbsp;rows of alternating hexagonal pores on the radial walls, which neaidy or, iu somenbsp;oases, quite cover the walls. The medullary rays are composed of a single layer ofnbsp;thin, short, cells, each of which is covered on the radial side with numerous finenbsp;dots or puuctations. The rays are from 1 to about 20 cells high, the average numbernbsp;being perhaps 8 or 10, A large number are composed of only 1 or 2 cells. Thenbsp;annual rings are rather indistinct, yet can be made out.

As far as I now know, only two species of Araucarioxylon have been described from the United States, A. arizonicum Kn., from the Triassic or Lower Jurassic ofnbsp;New Mexico and Arizona, and A. ri?-{/inianuni Kn., supposed at first to belong to thenbsp;Potomac formation, hut now known to he from the Trias of Virginia. These speciesnbsp;differ markedly from the one under disonssion. With the A. u)-feonicamithasalmost nonbsp;points in common, while it differs from the A. viryinianum iu important particulars.

The only sections of the fossil wood that have yet been made were cut from a specimen taken from the cycad bed proper, and not from the principal fos.sil forest, but it often hajipensthat only one species c,T,n he found iu such a forest. It is therefore probable that the same structure would he shown by the other specimens. I confess to anbsp;little surprise at finding that this structure represents the Araucarian rather thannbsp;the Sequoian type of conifers, since, iu the East at least, these two types characterize the Trias and Potomac, respectively, no Araucarian specimens having been foundnbsp;in the Potomac and no Sequoian specimens in the Trias. Aud generalijn the Arau-oarian type is more ancient. This evidence therefore points to a lower instead of anbsp;higher horizon.'

SUBKINGDOM SPERMATOPHYTA (Phanerogams).

Diagnosis.�Annual rings very distinct, or 4 to 8 rows of very thick-walled fall wood; spring wood of large but thick-walled cells; medullary rays in a single series of from 3 to 12 or 15 cells; these short, covering the width of some 4 to 6 or 8 wood cells, provided with a singlenbsp;series of small punctations; wood cells with 1 or 2 rows of hexagonalnbsp;or rarely nearly round punctations.

Discussion.�Transverse section: This section shows the annual rings to have been very plainly marked. The spring wood is made up ofnbsp;very large although thick-walled cells, which begin very abruptly at thenbsp;fall wood. The cells gradually decrease in size until the last 5 or 8nbsp;rows of cells are very thick.

Tangential section: The medullary rays as seen in this section are quite numerous, in a single series of from 3 to sometimes as many as 15nbsp;superimposed cells. The wood cells as seen in this section do not seemnbsp;to have been provided with punctations or other markings (PL OLIX,nbsp;Fig. 3).

Eadial section: As the material has been very finely preserved, this section shows remarkably well. The wide cells of the spring wood arenbsp;jirovided with usually 2 longitudinal rows of hexagonal pores, whichnbsp;quite cover the walls (PI. CLVIIl, Pig. 1). Occasionally in cells ofnbsp;unusual width the pores while in 2 series are only slightly compressednbsp;(PI. CLIX, Pig. 4). Usually when but 1 row is present they arenbsp;hexagonal and occupy the center of the cell (PI. OLVIII, Pig. 2).

The inner pores in these punctations are relatively small and slightly elongated in a direction at right angles to the cells.

The medullary rays as seen in this section (PI. CLVIIl, Pig. 4) are short, covering the width usually of 4 or 5 wood cells, although occasionally longer and covering as many as 8 cells. They are providednbsp;with a single row of small bordered pores so arranged that one comesnbsp;over each wood cell, or occasionally there may be two over a wood cellnbsp;(PI. OLIX, Pig. 1). The inner pore is minute.

LOWER CRETACEOUS FLORA.

tbe United States, and it is quite unlike either of the others. From A. arizonioum Kn.,' a species found iu the Triassic or Lower Jurassic,nbsp;it difi'ers in having a clearly marked annual ring, usually hexagonalnbsp;pores and no markings in the tangential walls of the wood cells. Fromnbsp;A. virginianum Kn.,^ a species of the Trias of Virginia, it differs in thenbsp;annual rings, in the less number of medullary ray cells, and in havingnbsp;the cells of the ray short juinctate.

At Professor Ward�s suggestion I take pleasure in naming this very distinct species in honor of Mrs. Jenney, who discovered this block ofnbsp;wood among the fragments of cycadean trunks.

Localitii.�Oycad bed 2 miles southwest of Miunekahta Station, South Dakota. Collected by Mrs. Mary Hopperton Jenney, September 7,1892.

3. LOWER CRETACEOUS FLORA OF THE BLACK HILLS, OTHER THAN CYCADEAN TRUNKS AND SILICIFIED WOOD.

As already shown, the principal contribution to the Lower Cretaceous flora of the Black Hills was made by Prof. Walter P. Jenney in 1895nbsp;from the Hay Creek coal field of Crook County, Wyoming. The present chapter therefore consists chiefly of Professor Fontaine�s reportnbsp;upon this collection. The only other forms included in it are the fewnbsp;that were collected by Professor Jenney and myself on the westernnbsp;slope of Eed Canyon, about 3 miles southwest of Minnekahta station,nbsp;half a mile southwest of Matties Peak, and immediately over the ridgenbsp;to the west of the principal fossil forest. These were also determinednbsp;by Professor Fontaine and reported upon in a letter dated January 10,nbsp;1894, which report was embodied almost entire in my paper on the Cretaceous Eim of the Black Hills.� His remarks on the species will be introduced in their systematic place.

Professor Fontaine�s report on the Jenney collection from the Hay Creek coal fleld is as follows: ^

NOTES ON LOWER CRETACEOUS PLANTS FROM THE HAY CREEK COAL FIELD, CROOK COUNTY, WYOMING.

In the summer of 1894, Prof. W. P. Jenney collected a considerable number of fossil plants in Wyoming, and sent them to Mr. Lester F.nbsp;Ward, Avho referred them to me for examination.

3 nbsp;nbsp;nbsp;Journal of Geology, Vol. 11, No.3, Chicago, April-May, 1894, pp, 259-260.

^ The only modifications that it has been found necessary to make in this report relate to the purely systematic part. Mr. Seward in his quot;Wealden Flora has made a careful revision of the principalnbsp;quot;Wealden genera and has changed many of the names, substituting modern ones for the older Carboniferous genera to which the species had been improperly referred. In most such cases I have adoptednbsp;his suggestions, but have introduced full aj�^nonyray, so that no possible confusion can arise.

Professor Fontaine simply described the species and arranged them in a general way under the heads Equiseta, Ferns, Cycads, Conifers, etc. I have changed his arrangement very little, and only to makenbsp;it conform as nearly as possible to the system of Engler and Prantl. The higher subdivisions havenbsp;been supplied by me. I am also responsible for all the footnotes.�l. f, w.

Professor Jenney in the same summer wrote a number of letters to Mr. Ward, giving the localities and horizons of the fossils, along withnbsp;other points necessary to throw light on their occurrence. In order tonbsp;give an intelligible account of these fossils it will be necessary for menbsp;to quote from these letters. As Professor Jenney states that his subdivisions of the formation containing the fossils are subject to changenbsp;if called for by further field study, this qualification must be borne innbsp;mind.

Professor Jenney made his collections of plant fossils in the Hay Creek coal field of Crook County, Wyoming, a region located 40 milesnbsp;northwest of Deadwood, South Dakota. A number of his localities arenbsp;found on Pine Creek and Oak Creek. In one of his letters he says regarding these creeks: �Pine Creek and Oak Creek are two small streamsnbsp;entering the Belle Pourche, draining the area bet ween that river andnbsp;Hay Creek, and are part of the Hay Creek coal field of which Barrettnbsp;post-office is the center.� This statement, with the data given for eachnbsp;locality where plants were collected, will fix their isosition with sufficientnbsp;accuracy. Before the examination made by Professor Jenney of thisnbsp;region, Hewton�s Dakota group was supposed to extend down to andnbsp;rest upon the Jurassic. Professor Jenney, as the result of his fieldnbsp;work, and influenced by geological data alone, was led to subdivide thenbsp;Dakota of Newton into several horizons. These will be given later.

Mr. Ward, on examining the plants, recognized their striking resemblance to Lower Potomac and Kootanie plants. As I had studied the former, he sent Professor Jenuey�s plants to me for determination. Professor Jenney, on stratigraphical and lithological grounds, was led tonbsp;make the following provisional subdivisions of the Dakota group ofnbsp;Newton, as exhibited in the Hay Creek region of Wyoming. I quotenbsp;from his letter to Mr. Ward:

1. nbsp;nbsp;nbsp;The Dakota sandstone, with characteristic plant remains, the base a massive

sandstone of variable character with respect to hardness, per cent of iron, etc....................................................................... 100

2. nbsp;nbsp;nbsp;Clay shales, sandstone shales, and soft sandstones, with, locally, beds of car

bonaceous shale and plant remains. Plants of modern type. * nbsp;nbsp;nbsp;*nbsp;nbsp;nbsp;nbsp;* At

base of this member a massive cross-bedded sandstone 50 feet in thickness. 150 Contact stratum, a breccia of clay and sandstone, marking unconformity.

3. nbsp;nbsp;nbsp;Massive sandstone, 40 feet, underlain by drab clay shales and carbonaceous

4. nbsp;nbsp;nbsp;Soft sandstones, clay shales, and clays, with one workable seam (3 to 5 feet

5. nbsp;nbsp;nbsp;Ash colored clays with calcareous nodules, no fossils observed; near top, at

6. nbsp;nbsp;nbsp;Jurassic claj'S and shell limestone, with marine fossils, Belenmites, (Istrea,

Professor Jenney, in another letter, states that his later investigations led him to conclude that No. 5 of the preceding section is com-])osed of Jurassic shallow-water deposits, and that they are not Lower Cretaceous. He says the beds carry often large trunks and limbs ofnbsp;fossil wood, and, in the layers of impure limestone, a few small '\,mmon-ites, but near the top of No. 5, just below the contact with the base ofnbsp;No. 4 Cretaceous, occurs a bone-bearing bed with large elongated vertebrat and fragments of leg and thigh bones, all in a poor state ofnbsp;preservation.

He goes on to say that there are evidences that the land'was rising at the close of the Jurassic, that some of the beds of No. 5 may be ofnbsp;brackish- or fresh-water origin, and before the deposition of the lowestnbsp;beds of the coal series (those of division No. 4) the land was abovenbsp;water and had suffered quite an extensive denudation. The evidencenbsp;also indicates that the workable and lowest beds of coal were depositednbsp;in basins, channels, of valleys in the eroded Jurassic.

Professor Jenney states that he found in the Dakota group of Newton evidences of unconformity between No. 1 and No. 2, and between No. 2 and No. 3, but was unable to find any between No. 3 and No. 4,nbsp;while there is great unconformity between No. 4 and the Jurassic.

These extracts from Professor Jenney�s letters show that, from strati-graphical evidence, the Dakota group of Newton, which has hitherto been supposed to contain no strata older than the typical Dakota'withnbsp;dicotyledons, and to extend as a unit down to the Jurassic, is reallynbsp;divided by two marked unconformities into at least three members.nbsp;The strata of division No. 1 contain the dicotyledons of the ty^jicalnbsp;Dakota, while those of No. 2 and the lower divisions do not shownbsp;these, but a quite difi'erent flora, whose age will be discussed in thisnbsp;paper.

If Professor Jenney is right, as he no doubt is, in his conclusion that the laud rose after the Jurassic submersion, and then, after an interval,nbsp;vegetation established itself on it finally in amounts sufficient to formnbsp;coal beds, it follows that even the oldest of the plants described in thisnbsp;paper are decidedly younger than Jurassic. Here we have a flora thatnbsp;established itself after the retreat of the Jurassic sea. But in the casenbsp;of plants in the Trinity group of Texas, as Professor Hill shows, wenbsp;have a difi'erent condition of things, for the sea advanced upon thenbsp;laud, finding an established flora, whose remains it swept away andnbsp;preserved in the beds then formed. The same is true of the Lowernbsp;Potomac fossil plants of Virginia. In the case of these two groups ofnbsp;fossil plants, the geological conditions do not indicate positively thatnbsp;they are younger than Jurassic, for we may have the remains of anbsp;Jurassic flora preserved in the lowest beds of the Lower Oretaceous.nbsp;Professor Jeuney�s discovery of fossil plants is especially fortunate innbsp;the fact that, according to the stratigraphy, they are clearly and distinctly younger than the Jurassic, for they are found in strata that

rest upon Jurassic beds, aud in addition an erosion interval separates the two. When we take into consideration the want of conformity ofnbsp;the Jurassic and these Lower Cretaceous beds, as well as the lapse ofnbsp;time required for a flora to establish itself on the land newly emergednbsp;from the Jurassic sea, it is surprising to find so many Jurassic tyjiesnbsp;surviving in this lower division of the Lower Cretaceous.

As Professor Jenney collected his plants from several horizons, and at diflerent localities, it will be necessary, before passing to the description of the species, to give some account of the geological horizon ofnbsp;the diftereut localities from which the plants were obtained. The following statements give the localities from which plant fossils werenbsp;obtained, with their position in the Lower Cretaceous group, as givennbsp;by Professor Jenney on labels accompanying each package of fossils.nbsp;It will be noted that he fixes their geological position by referring thenbsp;horizon in some cases to the Jurassic below, and in others to the typicalnbsp;Dakota sandstone above, with dicotyledons as the jiredominant plants.nbsp;This latter will be mentioned simply as the Dakota sandstone.

Professor Jenney determines the following localities as lying 60 feet below the base of the Dakota sandstone:

1. nbsp;nbsp;nbsp;Bed of carbonaceous shales in a cliff in the east bank of Oaknbsp;Creek, 2 miles below Bobbin�s ranch, Crook County, Wyoming. Thisnbsp;horizon is in his division No. 2 of Newton�s Dakota group, which is thenbsp;uppermost of the divisions made by Professor Jenney of the stratanbsp;underlying the typical Dakota. This horizon is the highest in divisionnbsp;2 which has yielded fossil plants. In the description of the species itnbsp;will be referred to as Cliff in east bank of Oak Creek.

2. nbsp;nbsp;nbsp;Cliff's along the north side of Bed Water Valley, about 4 milesnbsp;south of Larrabee�s coal mine. These localities will be designated Cliffnbsp;along the north side of Bed Water Valley.

3. nbsp;nbsp;nbsp;The next lower horizon at which plant fossils were found is locatednbsp;by Professor Jenney at 100 feet below the base of the Dakota sandstone. On this horizon, and still in division No. 2, plants were foundnbsp;at a cliff on north side of Pine Creek, 2 miles above (west of) Mrs. Dor-sett�s ranch. This will be referred to as Cliff* on north side of Pinenbsp;Creek.

4. nbsp;nbsp;nbsp;Cliff on the south side of Pine Creek, 2^ miles above (west of) Mrs.nbsp;Dorsett�s ranch. This will be referred to as Cliff on the south side ofnbsp;Pine Creek.

5. nbsp;nbsp;nbsp;Bed of carbonaceous shales in Boll in�s tunnel, 14 miles southesstnbsp;of Bobbin�s ranch, on Oak Creek. This will be referred to as Carbonaceous shales in Bollin�s tunnel.

6. nbsp;nbsp;nbsp;Cliff' on Oak Creek at Bobbin�s ranch, 6 miles northeast of Barrett,nbsp;Wyoming. This will be designated as Cliff on Oak Creek, at Bobbin�snbsp;ranch.

The following localities, lying in Professor Jenney�s third division of Newton's Dakota, were located by him about 150 feet above the top of

the Jurassic, aud about 170 feet below the base of the typical Dakota, or his division No. 1:

1. nbsp;nbsp;nbsp;Bed of shales in cliff on the north side of the valley of the Southnbsp;Fork of Hay Creek, 2^ miles west of Barrett post-office. Crook County,nbsp;Wyoming. This locality will be designated as Cliff on the north, sidenbsp;of the valley of the South Fork of Hay Creek.

2. nbsp;nbsp;nbsp;Bed of shales under the third sandstone, Barrett, Wyoming. Thisnbsp;locality was not given so precisely as some of the others, and it will benbsp;referred to as Shales under the third sandstone, Barrett.

3. nbsp;nbsp;nbsp;From John Barr�s tunnel, 1 mile north of Forks of Hay Creeknbsp;post-office. Crook County, Wyoming. This will be designated as Johnnbsp;Barr�s tunnel.

J. Locality not given. The package of fossils was marked simply as coining from the third division of Newton�s Dakota group, 150 feetnbsp;above the top of the Jurassic. The locality is probably the same asnbsp;No. 2 of this list, and it will be referred to as Locality unknown. Horizon 150 feet above the Jurassic.

The next horizons in descending, at which fossils were found, according to Professor Jenney, occur in his division No. 4, of Newton�s Dakota grouj), and they are probably essentially the same, but from the distances given by Professor Jenney for them above the Jurassic, there isnbsp;some variation in their height above that formation. This variation,nbsp;however, is not greater than might be expected from varying thicknessnbsp;in the beds underlying them, which are superposed immediately on thenbsp;Jurassic. I give the localities aud the distances determined by Professor Jenney at each, from the iilant-bearing bed down to the Jurassic:

1. nbsp;nbsp;nbsp;Shale over the lowest coal bed, Larrabee�s shaft, Barrett, Crooknbsp;County, Wyoming. This stands from 50 to 75 feet above the top of thenbsp;Jurassic, and the locality will be referred to as Shale over the lowestnbsp;coal, Larrabee�s .shaft.

2. nbsp;nbsp;nbsp;Bed of shales over coal, T. 54, E. 61, sec. 36, 2 miles southeast ofnbsp;Barrett, Crook County, Wyoming, about 30 to 50 feet above the topnbsp;of the Jurassic. This will be referred to as Shales over coal, 2 milesnbsp;southeast of Barrett.

3. nbsp;nbsp;nbsp;Bed of highly carbonaceous shale 50 feet above the top of thenbsp;Jurassic, Webster�s ranch, 4 miles northeast of Beulah, Crook County,nbsp;Wyoming. This will be referred to as Carbonaceous shale, Webster�snbsp;ranch.

4. nbsp;nbsp;nbsp;The lowest horizon in No. 4 that promised fossil plants is a bed ofnbsp;shales at the contact of the Cretaceous with the Jurassic, at Lon Cottle�s ranch, 1 mile southwest of Barrett, Crook County, Wyoming.nbsp;This bed of shales is the lowest bed in division 4. Tlie locality will benbsp;referred to as Bed of shales, Lon Cottle�s ranch.

DESCEIPTIOIS^S OF THE SPECIES. Subkingdom PTERIDOPHYTA (Ferns and fern allies).

1889. Mquisetmn virginicuni Font.: Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 63, pi. i, figs. 1-6, 8; pi. ii, figs. 1-3, 6, 7, 9.

A single good specimen of a small Equisetum was obtained from the horizon 100 feet below the base of the Dakota sandstone, and anothernbsp;doubtful one from the horizon 150 feet above the Jurassic. It belongsnbsp;to the small type of Equisetum, with many branches and narrow teeth,nbsp;that is so characteristic of the Lower Cretaceous, and which containsnbsp;the species of E. Burchardti from the Wealden of Germany, and E. vir-ginicum from the Lower Potomac (Neocomian) of Virginia.

The plant is decorticated and does not show plainly the nodes and sheaths in any place. What indications may be seen point to thenbsp;possession of narrow acute teeth, like those of E. virginicuni. Thenbsp;size of the branches, their number, and the general facies of the plantnbsp;are features which strongly indicate that this is a species which cannbsp;not be separated from the Virginia plant.

The species was evidently a copiously branching one, for the best specimen, that from the horizon 100 feet below the Dakota sandstone,nbsp;shows a number of small stems diverging as if from insertion on anbsp;common stem. The insertion, however, is not visible.

The plant was found in one good specimen, that figured, in the cliff on the north side of Pine Creek and in a single stem of doubtful character at the horizon 150 feet above the Jurassic, at the cliff' on thenbsp;north side of the Valley of the South Fork of Hay Creek.

Class FILICALES Engler.'

FERNS.

Genus WEICHSBLIA Stiehler.^

Weichselia reticulata (Stokes amp; Webb) Ward n. comb.

1824. Pecopteris reticulata Stokes and Webb: Trans. Geol. Soc. London, 2d ser., Vol. I, p. 424, pi. xlvi, lig. 5; pi. xlvii, fig. 3.

1828. Lonchopteris MantelU Brongn.; Prodrome, p. 60, 199; Histoire, Vol. I, p. 369, pi. cxxxi, figs. 4, 5.

1838. Lonchopteris Huttoni Presl in Sternberg; Flora der Vorwelt, Vol. II, p. 166.

1844. nbsp;nbsp;nbsp;Pecopteris sp. Auerbach; Bull. Soc, Imp. Nat. de Moscou, Vol. XVII, Pt. I, p. 148,

1845. nbsp;nbsp;nbsp;Polypodites reticulatus (Stokes and Webb) Ung.; Synops. PI. Foss., p. 93.

1845. Pterophyllum Murchisouianum Goppert in Murchison�s G�ologie de la Russie, Vol. II, Pt. Ill, Pal�ontologie, p. 501, pi. G, figs. 5, 6a (non fig. 3).

1845. nbsp;nbsp;nbsp;Pterophyllum fiUcinum G�ppert in Murchison�s G�ologie de la Russie, Vol. II,

1846. nbsp;nbsp;nbsp;Pecopteris Murchisoniana (G�pp.) Auerbach and Freers: Bull. Soc. Imp. Nat. de

1846. Pecopteris Auerbachiana Rouillier: Bull. Soc. Imp. Nat. de Moscou, Vol. XIX, Pt. II, p. 412.

1849. Pecopteris Auerbachiana Rouillier: Op. cit., Vol. XXII, p. 16, pi. J, fig. 55.

1852. Alethopteris reeentior Ett.: Abh. d. k. k. geol. Reiehsanst., Vol. I, Abth. Ill, No. 2, p. 16, pl. iii, figs. 17,18.

1854. nbsp;nbsp;nbsp;Anomopterissp. Stiehler; Zeitschr. d. deutsch. geol. Gesellschaft, Vol. VI, p. 661.

1855. nbsp;nbsp;nbsp;Anomopteris Ludowiooi Stiehler: Bericht d. naturwiss. Vereins d. Harzes f. 1853

1857. nbsp;nbsp;nbsp;Weichselia Lndovicai Stiehler; Zeitschr. d. gesammt. Naturwiss. z. Halle, Vol.

1858. nbsp;nbsp;nbsp;Weichselia Ludovieai Stiehler: Palaeontographica, Vol. V, Lieferuug 3, p. 73,

1865. Pleris reticulata (Stokes and Webb) Ett.: Die Farnkriiuter der Jetztwelt, p. 117. 1869. Alethopteris Ettingshausii Schimp.: Trait� de Pal. V�g., Vol. I, p. 569.

1869. nbsp;nbsp;nbsp;Lonchopteris reeentior (Ett.) Schenk: Palaeontographica, Vol. XIX, p. 4, pl. i,

1870. nbsp;nbsp;nbsp;Asplenites klinensis Trautschold, in pt.: Nonv. M�m. Soc. Imp. Nat. de Moscou,

1890. Pecopteris Peyleriana Nathorst (in pt.): Denkschr. Wien. Akad., Vol. LVII, p. 48, pl. iv, f. 3.

* In view of the imperfect Btate of our knowledge of fossil feins no attempt will be made in this paper to assign the genera to the now recognized famiiies, Osniundaceai Hynienophyliacere,nbsp;Schizmacem, Polypodiacem, etc., especially as Engler and Prantl�s great work has not at this writingnbsp;embraced this part of the vegetable kingdom.

' ^ The genus Weichselia was founded in 1858 (Palaeontographica, Vol. V, p. 73) by August Wilhelm Stiehler for the species TT. Ludowicre. which Mr. Seward reg.ards as identical with Lonchopteris Man-telli Brongn. (Histoire, Vol. I, p. 369, pl. cxxxi, figs 4, 5.) Lonchopteris is a Paleozoic genus and thisnbsp;form had to be called by a different name.

1891. Weichselia erra/ica Nathorst: Arch. Ver. Freund. Nat. Mecklenb., Jalirg. XLIV, p. 24.

1894. Weicliselia MantelU (Brougn.) Seward: Wealdeii Flora, Ft. I, p. 114, ligs. 12, 13 on p. 120, pi. X, fig. 3.

The horizons in division No. 2 made by Professor Jenney in Newton�s Dakota, lying 60 and 100 feet below the Dakota sandstone, contain innbsp;abundance a fern that is so close to Schenk�s Lonchopteris recentior,nbsp;referred by Seward to Weichselia MantelU, that it can not be separatednbsp;from that species.

Schenk in his work, Die fossilen Pflanzen der Wernsdorfer Schichten (Palaeontographica, Vol. XIX), j). 4, pi. i, figs. 2-6, describes and figures fragments of a fern with reticulate nervation that was obtainednbsp;from the Wernsdorf beds of the northern Carpathians, which are ofnbsp;Urgonian age. In the size, shape, and mode of insertion of the pinnules, in the character of the nervation, and, indeed, in all importantnbsp;points, the agreement between the Wyoming and European plants isnbsp;very close.

Schenk is no doubt correct in his supposition that this fern is bipin-nate. It is a rather peculiar fact that in all the numerous specimens coming from the Hay Creek coal field and examined by me there arenbsp;none that show the insertion of the ultimate pinnm on a primary one.nbsp;The specimens are all small bits of ultimate pinn�, as were those ofnbsp;Schenk, and show only a few pinnules. From the imprints left on thenbsp;stone, and the amount of carbonaceous matter left by the pinnules, wenbsp;must conclude that they were thick and leathery in nature. Owing tonbsp;this, in most of the specimens it is difficult to see the details of the nervation. Some of the pinnules approach in shape very near to LoncJiop-teris MantelU Brongn., from the WT^alden of England and France, fornbsp;there is some variability in them, although for a fern this is surprisinglynbsp;small. Schenk says of his form that it is with difficulty to be separatednbsp;from the Wealden species, and the Wyoming forms make still more doubtful the propriety of making two species of them. I have in PI. CLX,nbsp;Figs. 2 to 4, endeavored to give average forms. Fig. 2 represents thenbsp;terminal portion of an ultimate pinna with pinnules of average size.nbsp;Fig. 3 gives this enlarged three diameters, to show the nervation. Fig.nbsp;4 gives a portion of an ultimate pinna lower down than the portion givennbsp;in Fig. 2 and represents pinnules somewhat larger than those of Fig. 2,nbsp;being the average of the larger pinnules possessed by this fern. Itnbsp;should be noted that in the Hay Creek pinnules their margins are oftennbsp;bent under and the lamina on each side of the midrib is convex in form,nbsp;giving the pinnule something of the aspect of an Alethopteris, a featurenbsp;mentioned by Schenk as shown in the Wernsdorf plant.

Weichselia reticulata is one of the most common plants in Jenney�s second division, and forms nearly all of the material obtained at certain localities. This is the case with the collections made from cliffsnbsp;along the north side of Red Water Valley, cliff on the south side of

Pine Creek, carbouaceous shales in Eolliu�s tunnel, and dill on Oak Creek at Bobbin�s ranch. Besides these localities, numerous specinbsp;mens occur at the cliff in east bank of Oak Creek.

It thus seems to be abundant on both plant-bearing horizons in division No. 2 of Jenney, that 60 feet and that 100 feet below the basenbsp;of the Dakota sandstone, and it is without doubt one of the mostnbsp;characteristic plants of this division. No trace of it has so far beennbsp;found in the divisions of the Lower Cretaceous lying under No. 2. Itsnbsp;great abundance in division No. 2 and its absence in the underlyingnbsp;divisions indicate a change in the flora which is in keeping with thenbsp;diflei�ences seen in the other plants of the two portions of the Lowernbsp;Cretaceous.nbsp;nbsp;nbsp;nbsp;'

Both the specimens figured are from the black carbonaceous shales in Eollin�s tunnel.

1844. Cycadites Altkausii Bunker: Programm d. hoheren Gewerbschule in Cassel, 1843-1844, p. 7.

1846. Pecopteria Althausii Bunker: Mon. d. Norddeutsch. Wealdenbildung, p. 5, pi. ii, fig. 2.

1846. Pecopteriapolydactyla G�ppert in Bunker: op. cit., pj 5, pi. vii, fig. 4.

1846. Alethopteria elegans G�ppert in Bunker: op. cit., p. 8, pi. vii, figs. 7, 7a.

1852. Alethopteria Goepperti Ett.: Abb. d. k. k. geol. Reichsanst. Wien, Vol. I, Abth. Ill, No. 2, p. 16, pi. V.

1869. nbsp;nbsp;nbsp;Laccopteris Goepperti (Ett.) Schimp: Trait� de Pal. V�g., Vol. I, p. 582; Atlas,

1870. nbsp;nbsp;nbsp;Pecopteria explanata Trautschold: Nouv. M�m. Soc. Imp. Nat. de Moscou, Vol.

1871. nbsp;nbsp;nbsp;Matonidium Goepperti (Ett.) Schenk: Palaeontographica, Vol. XIX, p. 220, pl.

1888. Alethopteria polydactyla (G�pp.) Schenk: Bie fossilen Pflanzenreste, p. 39.

1891. Laccopteris polydactyla (G�pp.) Sap.: Plantes jurassiques. Vol. IV, p. 384.

This fern, described by Schenk as abundant in the Wealden formation of northern Germany, and found by Heer in the Wealden of Portugal, is one of the most common plants at the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pine Creek. Itnbsp;occurs also very rarely in the carbonaceous shales in Eollin�s tunnel. Itnbsp;has not yet been found at any other localities or on any other horizon.nbsp;Schenk�s specimens as described and figured in Die Foss. Flora dernbsp;Norddeutsch. Wealdeuformation, pp. 17, 18, pl. vi, fig. 5; pl. vii, figs.nbsp;1, la-c, 2, 2a (Palaeontographica, Vol. XIX, pp. 220, 221, pl. xxxvii,nbsp;fig. 5; pl. xxxviii, figs. 1, la-c), show much more of the plant than cannbsp;be seen in the fossils from the Hay Creek beds. These are always frag-

meuts of ultimate pinnae. They are pinnae of both the sterile and fruiting forms of the fern. In their dimensions the pinnules are in most cases larger than those ligured by Schenk, and smaller than those ofnbsp;Heer, given on pi. xv of his Contributions a la Flore Fossile du Portugal. The agreement in all essential jioints of the Hay Creek fossilsnbsp;with those from both European regions is exact. The fructified pinnules mostly carry sori from their tips, and they are proportionally verynbsp;large, so as to cover the entire lamina on each side of the midnerve.nbsp;The sori show a proportionally large and distinct depression in theirnbsp;center. Fig. 5 gives average sterile pinnules, and Fig. G representsnbsp;these enlarged two diameters, to show the character of the nerves. Fig.nbsp;7 represents the fertile pinnules, and Fig. 8 gives these enlarged twonbsp;diameters, to show the sori.

1890. Pecopteris Geyleriana Nath.: Denkschr. d. Wien. Akad. d. Wiss., Vol. LVII, p. 48, pi. iv, fig. 1; pi. vi, fig. 1.

This fern, coming from the Lower Cretaceous of Japan, was first described and figured by Hathorst in his Beitriige zur Mes. Floranbsp;Japans (Denkschr. Wien. Akad., Vol. LVII), p. 48, jd. iv, fig. 1; pi. vi,nbsp;fig. 1. It was later found by M. Yokoyama at additional localities innbsp;the same country and formation, who noticed the plant in the Journalnbsp;of the College of Science, Imperial University of Japan, Vol. VII, Pt.nbsp;Ill, 1894, pp. 219-220, pi. xxi, fig. 12; pi. xxiii, fig. 1, la; pi. xxviii, fig.nbsp;5, giving some excellent figures. The figures of both Nathorst andnbsp;Yokoyama show that the plant possesses some characteristic featuresnbsp;that render it rather easy to identify. The Japanese forms are fiir morenbsp;complete than those of the Hay Creek beds, but fortunately the xgt;ecul-iarities are found mostly in the pinnules, and these are well shown innbsp;the American fossil.

In the Hay Creek strata Pecopteris Geyleriana is always found in detached fragments of ultimate pitinae and mostly associated with If eich-

* There are probably no true representatives of the genus Pecopteris in the Cretaceous, but in default of the fruiting organs a large number of forms of Mesozoic age liave from time to time been referrednbsp;to this genus on account of the similarity of the fronds and their nervation. In recent times therenbsp;has been a strong movement in the direction of assigning such forms to more modern genera, and innbsp;due time all will probably be so referred. They are found to fall under several different genera, butnbsp;the majority of them probably belong to the genus Cladophlebis, established by Brongniart himselfnbsp;in 1849 (Tableau, p. 25), for the reception of a number of those that he had formerly included undernbsp;Pecopteris. Among other Mesozoic genera to which these forms have been referred are Weiebselia ofnbsp;Stiebler, Matonidinm of Schenk, and Scleropteris of Saporta. A number have also been placed in thenbsp;living genera Pteris, Thyrsopteris, and Gleichenia. This, however, is probably going almost as farnbsp;to the opposite extreme. Until the subject shall have been properly monographed we shall be obligednbsp;to follow the authorities we have.

seiia reticulata. While it is much less abuiulant than this latter, both occur in the same condition of preservation, which shows that the fragments had been transported some distance from the place ot theirnbsp;growth. The specimens of this Pecopteris are nowhere very abundantnbsp;and the fragments of ultimate pinn� are never very large. Still thenbsp;pinnules show their character very distinctly and the number of di�erentnbsp;Ijarts is great enough to indicate almost all the variations mentionednbsp;and illustrated by Yokoyama. The pinnules of all the Hay Creek specimens are quite small. They must have been thick and leathery, as isnbsp;indicated by Yokoyama�s figures. They must have been quite durable,nbsp;for they leave a thick layer of carbonaceous matter that obscures thenbsp;nerves. Yokoyama mentions as a peculiar feature that the lowest pinnules on the front of the rachis of the ultimate pinna; are often falcatenbsp;backward instead of forward, and he says that they aie mostly bluntnbsp;and that the views are in most cases indistinct. All these features arenbsp;seen in the specimens from the Hay Creek beds. The midnerve is generally persistent to near the tip and it sends off on each side forking lateralnbsp;nerves, which, owing to the thickness of the carbonaceous film, are notnbsp;often seen. Another peculiarity seen in both the Japanese and Haynbsp;Creek specimens is the rounding off of the pinnules at their base, so asnbsp;to form ears, and the posterior ear is usually larger than the anteriornbsp;one. The pinnules are more or less triangular in shape.

PI. CLX, Pig. 11, represents a fragment of an ultimate pinna with pinnules of the largest size that were seen. Pig. 12 gives those ofnbsp;intermediate size, while Pig. 9 gives the smallest size. The enlargementnbsp;of Pigs. 9 and 12 and in Pigs. 10 an d 13 are four diameters.

This plant has been found on the horizon 60 feet below the Dakota sandstone, at the cliff in the east bank of Oak Creek, one specimen; andnbsp;a number of specimens on the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pine Creek; carbonaceous shalesnbsp;in Kolliu�s tunnel, and cliff on Oak Creek at Bobbin�s ranch.

The specimen represented by Pigs. 9 and 10 of PI. CLX is from Eollin�s tunnel; that by Pig. 11 is from the cliff on the north side ofnbsp;Pine Creek, and that by Pigs. 12 and 13 from the east bank of Oaknbsp;Creek, 2 miles below Bobbin�s ranch.

1828. Pecopteris borealis Brongu.: Histoire de.s V�g�taux fossiles, Vol. I, p. 351, pi. cxix, figs. 1, 2.

A single specimen of a plant so much like the Pecopteris borealis of Brongniart that it may be identified with it was found on the horizonnbsp;60 feet below the Dakota sandstone, at the cliff in the east bank of Oaknbsp;Creek. It shows a considerable portion of .an ultimate pinna with anbsp;number of pinnules that are quite well preserved. These are shown in

Fig. 13. The ultimate pinu� must have been quite long and have had closely set pinnules that were separate near their bases. The lowernbsp;surface of the rachis seems to have had a corded appearance, from thenbsp;existence of the rachis in the midst of a wing on each side, caused bynbsp;the union of the bases of the pinnules. The pinnules have the aspectnbsp;of those of Oladophlebis of the Jurassic type. They are small, broadest at their bases, inclined forward, more or less ovate and subacutenbsp;. toward their tips. The nerves are very distinct, as shown in Fig. 14.nbsp;The general aspect of the pinnules is much like those of the pinnulesnbsp;of the specimen ligured by Heer in Flor. Foss. Arct., Vol. I, pi. xliv,nbsp;figs. 5a, 5b. The rigid wing� on each side of the rachis in the Haynbsp;Creek i^lants makes the rachis of the ultimate pinna appear muchnbsp;thicker than it really is. Only two specimens were found.

A single mutilated specimen of a fern was found on the horizon 60 feet below the Dakota sandstone, at the cliff' in the east bank of Oaknbsp;Creek, that is probably a new species. The specimen shows only anbsp;fragment of an ultimate pinna with pinnules more or less distortednbsp;by pressure. Some of them, however, show their original characternbsp;pretty well. The description of the plant is as follows: Frond bipin-nate, pinnules remote, obliquely attached, falcate and acute, slightlynbsp;decurrent, midnerve slender and continuous to near the tip of the pinnules, where it splits up into branches. Lateral nerves going offnbsp;obliquely, forking once, the forking taking place near their insertion.

Although not enough material of this plant was obtained to permit the determination of its full character and the establishment consequently of a good species, it is not near enough to any species knownnbsp;to me to justify its being identified with any hitherto described. Wherenbsp;a plant from some new region possesses only a slight resemblance tonbsp;one previously described from some remote locality it appears to benbsp;better usage to regard them as different species. Still more is this truenbsp;if the two belong to different geological formations. It is true that thisnbsp;involves a multiplication of species, but the making of species, whichnbsp;can be easily merged into others if necessary, involves possible errorsnbsp;of less importance than the unjustified assumption that the same plantnbsp;existed in widely separated localities and survived through differentnbsp;geological periods.

The plant now in question is a good deal like Fecopteris virginiensis, which I have described in Monograph XV of the U. S. Geological Survey, from the Lower Potomac of Virginia; but it lacks the toothing,nbsp;which is a very persistent feature on the pinnules of that plant, beingnbsp;shown on them even high up toward the ends of the ultimate piume.

It is also like tlie narrower forms of the pinnules of CladoplileMs acuta, which is found in the Lower Potomac formation (see Mon. TJ. S. Geol.nbsp;Survey, Vol. XV, pi. xi, flg. 7), but the pinnules of this form arenbsp;closely placed and united at bases. A larger amount of material wouldnbsp;very probably justify its identification with GladophleMs acuta. Ournbsp;plant has an obvious resemblance to the fern from the Kootanie formation of British America which Sir William Dawson considers as identical with Heer�s Aspleniuni distans from the Jurassic of Siberia (seenbsp;Dawson on the Mesozoic floras of the Eocky Mountain region of Canada;nbsp;Trans. Eoy. Soc. Can., Sec. IV, Vol. Ill, 1885, p. 5, pi. iii, fig. 7). Butnbsp;the Kootanie plant is a fern with larger pinnules. Whatever its specific order may be, our plant belongs to a type which is quite characteristic of the later Jurassic and basal Cretaceous.

1899. Cladophlebis parva Font.; Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p.73, pi. iv, figs. 7, 7a; pi. vi, figs. 1, la, 2, 2a, 3, 3a.

At the cliff on the north side of the valley of the South Fork of Hay Creek and on the horizon 150 feet above the Jurassic a small fragmentnbsp;of a fern was found that appears to be identical with GladophleMs parvanbsp;of the Lower Potomac. For description of this species see Mon. U. S.nbsp;Geol. Survey, Vol.XV, p.73. The amount of material is much too smallnbsp;to permit its true character to be made out. However, the pinnules,nbsp;which are well preserved, are exactly like those of GladophleMs parva.nbsp;These look much like Jurassic forms of Cladophlebis, and are probablynbsp;survivors from the Jurassic. Several imjierfect specimens, which maynbsp;also be placed doubtfully in this species, were found on the horizon 100nbsp;feet below the Dakota sandstone, at the cliff on Oak Creek, Eobbiu�snbsp;ranch.

1881. Sphenopieria plwrinervia Heer: Contributions a la Flore fossile du Portugal; Section des Travaux gcologiques du Portugal, 1881, p. 13, pi. xi, figs. 6, 6b;nbsp;pi. XV, figs. 8, 8b, 8c.

The specimen identified doubtfully with Heer�s species is a portion of an ultimate pinna of a small fern. It shows a number of minutenbsp;pinnules that have lost their tips, but were evidently elliptical in form

� Splienopteris is another mainly Paleozoic genus of ferns to which Cretaceous forms probably ought never to have been referred. Many of them have gone into Onychiopsia, Cladophlebis, Scleropteris,nbsp;Dichopteris, Cyathea, Dicksonia, and Thyrsopteris, but a considerable number still remain, audit willnbsp;be imiiossible in this paper to assign them to their proper genera. They will therefore be left innbsp;this genus until a thorough revision can be made of the group.

and narrowing to tlieir base in sucb a manner tbat they were attached to the rachis almost by a petiole. They resemble Sphendpteris pluri-nervia enough to justify a doubtful identification with the species.nbsp;There is not enough material to permit the determination of a full specific character. Heer describes his plant in Gontr, a la Flor. Foss, dunbsp;Portugal, pp. 13-14, pi. xi, fig. G; pi. xv, fig. 8, as coming from thenbsp;Lower Cretaceous of Portugal. The plant in the Hay Creek seriesnbsp;occurs on the horizon 150 feet above the top of the Jurassic, at thenbsp;cliff on the north side of the valley of the South Pork of Hay Creek,nbsp;in only two specimens.

1889. Thyrsopteris pinnatifida Font.: Potomac Flora, Mon. U. S. Geol. Survey, Vol.

XV, p. 136, pi. li, fig. 2; pi. liv, figs. 4, 5, 7, 7a, 7b; pi. Ivii, figs. 7, 7a.

On the horizon 150 feet above the Jurassic and at the cliT or the north side of the valley of the South Fork of Hay Creek a small fragmentnbsp;of a fern was found, having a character unlike the others, and resembling Thyrsopteris pinnatifida of the Lower Potomac of Yirginia. Asnbsp;there is not enough material to permit its full character to be made out,nbsp;its identification must be doubtful. The fragment shows a piece of annbsp;ultimate pinna carrying several fragmental pinnules which have all thenbsp;character of those of Thyrsopteris pinnatifida. They have the samenbsp;size, shape, aud lobing of the pinnules of that plant when they occurnbsp;toward the ends of ultimate pinme, being quite small, elliptical in shape,nbsp;and cut obliquely into minute lobes and teeth.

1889. Thyrsopteris crassinerols Font.: Potomac Flora, Mon. U. S. Geol. Survey, Vol.

At the same locality and on the same horizon with the doubtful specimen of Thyrsopteris pinnatifida, another small specimen of a different fern was found. This has pretty strongly shown the features ofnbsp;Thyrsopteris crassinervis of the Lov'er Potomac of Virginia, but in thisnbsp;case also the amount of material does not justify a positive identification with that form. The specimen is very distinct in the featuresnbsp;shown. It is a jiortion of a penultimate pinna from toward its tip, thatnbsp;contains several short ultimate pinme. These have broadly ellipticalnbsp;liiunules that are united at the base. The upper basal pinnules, as is

� Professor Fontaine lias referred a large number of Potomac ferns to this living genus, perhaps correctly, but it would jirobably have been better to place them in Brongniart�s extinct genus Coni-opteris. For a brief account of the general subject see the Fifteenth Annual Report of the U. S.nbsp;Geological Survey, p. 383.

the case with Thyrsopteris crassinervis, are a good deal larger than the others, but it is not lobed as is the case with the corresponding pinnulesnbsp;of the Potomac plant. This is probably owing to the fact that the ultimate pinnae of the Hay Creek specimen come from a portion of thenbsp;penultimate pinna nearer its end than those of the Potomac form thatnbsp;show lobed basal pinnules. The nerves are strong and distinct.

1889. Thi/rsopteris elUptiea Font.: Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 133, pi. xxiv, fig.s. 3, 3a; pi. xlvi, figs. 1, la; pi. 1, figs. 6, 6a, 9; pi. li, figs.nbsp;4, 6, 6a, 6b, 7; pi. liv, fig. 6; pi. Iv, fig. 4; pi. Ivi, figs. 6, 6a, 7; pi. Ivii,nbsp;figs. 6, 6a; pi. Iviii, figs. 2, 2a.

This plant, which is abundant in the Lower Potomac strata of Virginia, and has been described in Monograph XV, p. 133, is rather rare ill the Hay Greek beds. So far as yet found it occurs on the horizonnbsp;150 feet above the Jurassic at two localities: Cliff on the north side ofnbsp;the valley of the South Pork of Hay Creek, and shales under the thirdnbsp;sandstone, Barrett, with one doubtful small fragment at the contactnbsp;of the Jurassic with the Cretaceous, Lon Cottles� ranch. At all thenbsp;localities only small, imperfect fragments were obtained, showing portions of ultimate pinnae. At the first-named locality the fragments arenbsp;larger, but the pinnules are not so well preserved. At the second locality the small bits of pinnie, with often very distinct pinnules, go to helpnbsp;form a mat of vegetation along with small fragments of Finns stisqua-ensis and Gzekanowslcia nervosa, that covers the cleavage surfaces of thenbsp;shale. The plants here seem from some cause to have been torn intonbsp;small bits, which, however, are very distinct in character.

The shale under the third sandstone at Barrett deserves a careful and j)rolonged search. It would no doubt yield many beautifully preservednbsp;specimens of those plants already made out and some new species, fornbsp;very suggestive fragments, too small to give any positive character,nbsp;may sometimes be seen. The shale is well fitted to preserve plantsnbsp;and is full of fragments. It is very fine-grained, gray in color, with anbsp;tinge of buff. It splits into lamin� as thin as jjaper, and the surfacenbsp;of these takes a perfect imprint of a plant. Unfortunately, only a verynbsp;small amount of this material was obtained. It is a noteworthy factnbsp;that this shale is physically strikingly like the carbonaceous shale atnbsp;Webster�s ranch, which Professor Jenuey places geologically 100 feetnbsp;below it. OzelcanowsMa nervosa and Finns susquaensis occur in both.nbsp;The only difference, as shown by the plants, is that the small Zamites,nbsp;Z. borealis, is common on the loAver horizon, while it is not found on thenbsp;upi)er, and Thyrsopteris elliptica occurs on the upper and not on thenbsp;lower horizon.

The specimen figured was found at the cliff on the north side of the valley of the South Pork of Hay Creek, 2^ miles west of Barrett.

Frond bipinnate; only the terminal portions of some of the ultimate piniise were seen. The ultimate ihiinae have their terminal portionsnbsp;long and narrow, with an unusnally gradual reduction in the size ofnbsp;the lobes and teeth which they carry, and which represent the pinnules of lower portions of the pinn� and frond. The lowest pinnulesnbsp;seen on the ultimate pinn� (Fig. 6) are united at base, very obliquelynbsp;inserted on the rachis, oblong in form, with margins notched as if fornbsp;incipient lobes. Toward the end of the pinu� the pinnules pass verynbsp;gradually, by diminution in size and increasing union, into lobes andnbsp;then into teeth. These lobes and teeth are narrowly ovate, acute, andnbsp;very oblique, diverging from the rachis (Fig. 8). The lobes have eachnbsp;a single nerve, which sends a branch to the upper margin or tooth. Innbsp;the notched lower piun� a midnerve sends off on each side a branchnbsp;into each incipient lobe.

It is obvious that not enough material is possessed to give certainly the character of this small fern. The long drawn out tips of the ultimate pinn�, with small dentate lobes and acute diverging teeth, appearnbsp;to be a new and constant character. The tqis of the i)inn� look likenbsp;portions of a twig of some conifer. These terminal portions seem tonbsp;have been rather easily broken off, for they form most of the imprintsnbsp;found. One of these bits, 18 mm. long, shows only the tooth-like lobes,nbsp;the width from tip to tip of which is only 2.5 to 3 mm. The plant looksnbsp;mnchlike Sphenopteris MantelU Brongn. [OnyoMopsis MantelK (Brongn.)nbsp;Sew.], and would have been so regarded were it not for the passage innbsp;the lower portions of the pinn� of the lobes into Thyrsopterid pinnules. At any rate it belongs to the kind of fern with narrow, rigidnbsp;j)innnles which appears common in the Lower Cretaceous, and ofnbsp;which Oiiychiopsis MantelU may be taken as the type.

This fern occurs sparingly on the horizon 50 feet above the Jurassic, at the shales over coal 2 miles southeast of Barrett.

1889. Thyrsopteris brevifolia Font.: Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 121, pi. xxiv, figs. 5, 5a, 5b, 5c, 5(1, 10.

This pretty little fern is one of the most common plants on the horizon 50 feet above the Jurassic at the shale over coal 2 miles southeast of Barrett, where its fragments cover thickly some of the cleavage surfaces of the shale, being mingled with fragments of Thyrsopteris denU-folia and T. pecopteroides. It never shows, in any imprint, more thannbsp;detached fragments of ultimate pinn�. These, however, are numei�ousnbsp;enough to give a pretty full representation of various portions ofnbsp;these pinn� from different parts of the frond. At the same time

gradations show connecting links between the detached portions. This plant was found in the Lower Potomac of Virginia, occurring at thenbsp;Dutch Gap Canal, in a ball of red clay or shale, which was embeddednbsp;in the layers of bluish-gray clay and sand that form the banks of thenbsp;canal. It was found nowhere else in that formation, and it is interesting to note that it occurs in the Hay Creek region, at only one locality,nbsp;in a shale that resembles that containing it at the Dutch Gap. Itsnbsp;description was given in Mon. XV, p. 121, pi. xxiv, figs. 5, 5a-d, and 10.

The larger number of imprints occurring in the Hay Creek beds enable us to see parts not shown in the Potomac fossils. These arenbsp;portions from lower down on the ultimate pinnae and parts of ultimatenbsp;pinnae from higher up toward the summit of the frond. All the partsnbsp;indicate a fern somewhat more robust than the Dutch Gap plant. Thenbsp;pinnules from the lowest portion of the pinnae and frond are still morenbsp;like Sphenopteris hymemphylloides Brongn. than any of the Potomacnbsp;specimens. The ultimate pinnae from both regions were evidently verynbsp;long and slender, and the Hay Creek specimens show that they endednbsp;in long drawn out and attenuated terminations. Especially is this truenbsp;of the pinnae from the upper part of the frond, as shown in Pigs. 12nbsp;and 14 of PI. CLXI. The deeply incised pinnules. Fig. 10, graduatenbsp;into elliptical lobes and teeth toward the ends of the pinnae. Thesenbsp;are shown in Figs. 12 and 14, Fig. 12 giving the lobed forms and Fig. 14nbsp;those with teeth. All this is clearly shown in the enlarged Figs. 11,13,nbsp;and 15.

1889. Thyrsopteris pecopteroides Font.: Potomac Flora, Mon. U. S. Geol. Survejf, Vol. XV, p. 135, pi. li, figs. 1, la.

This small, delicately incised fern was found by the writer in the Lower Potomac of Virginia at Fredericksburg, where it occurs quitenbsp;rarely. It occurs in the Hay Creek beds, on the horizon 50 feet abovenbsp;the Jurassic, at the shales over coal 2 miles southeast of Barrett, alongnbsp;with Thyrsopteris hrevifolia and T. dentifolia, being almost as commonnbsp;as the former. The specimens show only portions of the ultimate pinnm,nbsp;but some of these appear to come from parts of the frond lower downnbsp;than any seen in the Potomac fossils. Hence some of the pinnules arenbsp;somewhat larger than any belonging to the Virginia specimens andnbsp;show a greater tendency to lobing. These are given in Figs. 10 and 17.nbsp;At the same time pinnm from parts of the frond higher up than thosenbsp;seen in the Potomac specimens were obtained. These are very minute.nbsp;They are shown in Figs. 18 and 19.

It IS a noteworthy fact that the three ferns last described, viz, Thyrsopteris dentifolia, T. hrevifolia, and T. pecopteroides, occur together in comparative abundance on the horizon given by Professor Jenney atnbsp;30 to 50 feet above the Jurassic, at shales over the coal 2 miles south-

east of Barrett, while they are found nowhere else in the Hay Creek region. Only one small collection from this locality was placed in mynbsp;hands, and it is much to be desired that additional collections shouldnbsp;be made there. The shale preserves the plants well, it cleaves nicely,nbsp;and seems to be rich in fossils. Some bits indicate that other and newnbsp;forms may be found there. It is peculiar that so many parts of detached,nbsp;ultimate pinme are found at this locality with their terminal portionsnbsp;perfectly preserved, while in no case were the piniim seen attached to anbsp;rachis. The terminal portions of pinn� of delicate ferns like these arenbsp;usually the parts most poorly preserved.

1889. Thyrsopteris hrevipennis Font.: Potomac Flora, Mon.U. S. Geol. Survey, Vol. XV, p. 124, pi. xxxiv, figs. 3, 3a; pl.xxxvi,figs. 2, 2a; pl.xxxvii,ligs. 3,9; pl.xxxviii,

This species was described by the writer from the Lower Potomac in Monograph XV of the TJ. S. Geological Survey, page 124. In the Haynbsp;Creek beds were found several small fragments of ultimate pinn�,nbsp;carrying a few pinnules, of a fern that is apparently the same species,nbsp;but the amount of material is not sufficient to permit positive identification. They occur only on the horizon 150 feet above the Jurassic, atnbsp;the cliff on the north side of the valley of the South Fork of Hay Creek.

This is apparently a new Scleropteris that occurs at the same locality and horizon as Thyrsopteris pinnatifida and T. crassinervis, onnbsp;the South Fork of Hay Creek, 170 feet below the Dakota sandstone. Itnbsp;occurs in only one specimen, but that is characterized well enough tonbsp;justify its being provisionally made a new species.

The specimen shows a fragment of a long, slender ultimate pinna. The lobes, or rather jiinnules, are remote from one another and verynbsp;obliquely directed toward the ends of the pinna, so that they divergenbsp;very slightly from the rachis to which they are attached. They arenbsp;very small, narrowly ellipitical in form and decurrent at base, so as to

^quot;Where the material was scarce and doubtful, Professor Fontaioe did not always select specimens for illustration. It seemed to me all the more important that such cases should be illustrated in ordernbsp;that the occurrence of the species in the Black Hills might be fully attested. I have therefore hadnbsp;figures made, however imperfect, to support his notes.

2 This genus was established by the Marquis Saporta in 1872 (Plantes Jurassiques, Vol. 1, p. 364) to embrace a number of forms of Mesozoic ferns previously referred to Sphenopteris, Loxopteris,nbsp;Pachypteris, and Dichopteris, but without wholly absorbing these genera. The Lower Cretaceous ofnbsp;America contains some forms that fall distinctly within the limits of the genus.

form a comparatively wide wing. The nervation consists in each pinnule of a parent nerve that splits up into several branches whichnbsp;are directed very obliquely upward toward the tip of the pinnule.nbsp;One or more of the branches may be forked.

The shale which yields these plants at the cliif on the north side of the valley of the South Fork of Hay Creek is a fine-grained fissilenbsp;material, gray in color, with a slight brownish shade. It preserves thenbsp;plants beautifully, although most of those obtained are in small bitsnbsp;owing to the small fragments of the shale obtained. This is no doubtnbsp;due to the fact that the specimens come from weathered shale of sur-faces long exposed. Prom the character of this material there is littlenbsp;doubt that if specimens be taken from fresher rock, farther in from thenbsp;surface, larger and more complete imprints of the plants would benbsp;found. Only a small amount of the rock was obtained, and no doubtnbsp;prolonged and careful search would result in finding other plantsnbsp;Occasionally to be seen on the specimens are small bits and fragmentsnbsp;that indicate the existence of other plants besides those mentioned innbsp;this paper. In addition a number of the plants found here are notnbsp;found elsewhere, so that it is very desirable that additional collectionsnbsp;should be made at this spot.

Frond probably tripinnatifid. The ultimate pinme or pinnules are very small. Their tips are not preserved, but they were probably notnbsp;more than o �� m length. They are alternate and attached at annbsp;angle of about 4o with the principal racliis. They carry minute cirnbsp;cular lobes or pinnules that are united at base by a proportionallynbsp;broad wing. This latter is thick in texture and rigid, so that when thenbsp;rachis is seen from above the wing seems to be a part of it.' Hence thenbsp;rachis appears abnormally strong. When the underside of the rachisnbsp;is presented it is seen to be very slender. The pinnules or lobes becomenbsp;more and more united toward the tips of the ultimate pinnm. Theynbsp;are not more than three-fourths of a millimeter wide. In each lobe anbsp;nerve ascends from a very oblique insertion and splits in a flabellatenbsp;manner into two or more branches.

This minute Scleropteris is not near any described plant known to me. The best preserved specimens do not show enough to enable thenbsp;character of the plant to be made out fully, but enough may be seen tonbsp;indicatG that it is a pretty well marked new species. PI CLXII 4nbsp;gives the most complete imprint found.nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;70*?

It occurs in several specimens on the horizon 150 feet above the Jurassic at the cliff on the north side of the valley of the South Forknbsp;of Hay Creek, and has been found as yet nowhere else.

CRETAOEOUS FORMATION OP THE BLACK HILLS.

Asplenitjm: Dicksonianum Heer!

PI. CLXII, Figs. 6-8.

1874. AspleniumDicksoniaimm�ieeT: Die Kreide-Florader arctischenZone, K. Svensk. Vet.-Akad. Handl., Vol. XII, No. 6 (Fl. Poss. Arct., Vol. III, Pt. II), p. 31, pl. i,nbsp;figs. 1 (excl. b, c), laa, 2, 3, 3b, 4, 5 (excl. a, b, c).

The specimens represent the summits of ultimate pinnm of a fern which is decidedly like Asplenittm Diclcsonianum Heer, from the Komenbsp;beds of Greenland. It has also something of the character of thenbsp;widely diffused Potomac plant Thyrsopteris rarinervis. but is, I think,nbsp;nearer Heer�s plant.^

Glbighenia Zippbi (Corda) Heer!

Pl. CLXII, Fig. 9.

1846. Peeopteris Zippei Corda in Renss: Versteinerungeu d. biibm. Kreideformation, Abth. II, p. 95, pl. xlix, figs 2, 3.

1868. Gleichenia Zippei (Corda) Heer: Fl. Foss. Arct., Vol. I, p. 79, pl. xliii, figs. 4, 4b.

Some ends of the ultimate pinnm of a small fern with the facies of Gleichenia occur iu the collection. This is nearest to Heer�s G. Zippeinbsp;from the Kome beds, but the pinnules are rather more acute than mostnbsp;of those of that plant, and indicate that those on this plant lowernbsp;down are somewhat larger than those of 0. Zippei. The form is alsonbsp;something like Aspidimn heterophyllum of the Potomac formation, butnbsp;seems to be smaller and more delicate. It may, however, be the same.^

*T1i6 above is all tbat Professor Fontaine says in bis letter of January 10, 1894, about the three small fragments figured on Pl. CLXII, Figs. 6-8, which were collected by Professor Jenney and myselfnbsp;on the slope of Red Canyon iu the Minnekahta region. After examining the specimens he returnednbsp;them with labels, on all of which he wrote: � � Probably Asplenium Dicksonianum. � It is a significantnbsp;fact that neither this species nor the Potomac fern Thyrsopteris rarinervis Font., occurs in the Haynbsp;Creek collection. A comparison of these fragments with the fine specimens of Asplenium Dicksonianum collected by us near Evans quarry, in the true Dakota group (see infra, p. 704, Pl. CLXX, Fig. 1),nbsp;will be of interest.

2 The above description by Professor Fontaine was based chiefly on the specimen figured on Pl. LXXX, Fig. 9, but of which, at the time he examined it, scarcely more than 2 cm. were visible of thenbsp;upper part of the pinna. After its return I observed that the impression passed into the rock belownbsp;the exposed portion, and by a little skillful manipulation I succeeded in scaling off a piece of rocknbsp;and exposing the remainder that we here see, amounting to considerably more than 5 cm. The lowernbsp;lobes are somewhat more toothed than the upper ones, thus differing from Heer�s figures. They arenbsp;not pointed like Aspidium heterophyllum Font., and it seems to me probable that the impression maynbsp;represent a pinnule of Thyrsopteris pecopteroides Font.

Class CYCADALES Engler 1897.'

No unequivocal oycadaceous plants occur above the borizou lying ISO feet above the Jurassic. The only possible exceptions are the onenbsp;or two small fragments of leaves that occur at higher horizons, andnbsp;that look more like Zamites than any other plant. They show, however, neither basal nor terminal portions, and may be Nageiopsis.nbsp;Oycads of the type of Zamites described by Heer, so characteristic ofnbsp;the Kome beds of Greenland, are the only certain ones found in thenbsp;Hay Creek strata. On the horizon 150 feet above the Jurassic at Johnnbsp;Barr�s tunnel they are the most common plants. Elsewhere they arenbsp;rare. It is a noteworthy fact that this type of cycad seems to be thenbsp;most characteristic one in the Kootanie beds, as made known by Sirnbsp;William Dawson, and in the strata of similar age at Great Falls, Montana. Taking all these occurrences into consideration, it seems thatnbsp;this type is highly characteristic of the Lower Cretaceous, at least ofnbsp;North America.

1871 Zamites brevipennis Heer: K. Svensk. Vet.-Akad. Haudl., Vol. XII, No. 6 (PI.

Several well-preserved specimens of a small Zamites occur on the horizon 150 feet above the Jurassic at John Barr�s tunnel, and nowherenbsp;else which are identical with Z. hrevipennis obtained by Heer from thenbsp;Kome beds of Greenland and described by him in Vol, III of FI. Foss.nbsp;Arct. Ft. II, Pie Kreide-Flora des Arctischen Zone, p. 67, pi. xv, �gs.

8 9 10. They agree so far that even Heer�s largest and smallest forms of this plant can be duplicated from the Hay Creek beds. Fig. 10nbsp;agrees well with Heer�s larger forms, and Fig. 12 with his smaller. Thenbsp;nerves could not be made out, for it appears that they are not visiblenbsp;in this type when the upper surface of the plant is presented uppermost.

The plants must have had a coriaceous and double-leaf texture, for in the shale the leaf substance is to a large extent preserved, and maynbsp;be peeled off so as to remove all trace of the plant.

1 Xbe class Bennettitales (see supra, p. 598) does not include tlie foliage, fruits, etc., of cycadeau vegetation found in a fossil state, but only petrified trunks. W� are, tberefore, compelled to refer tbe former still to tbe class Gycadales and family Cycadacem. There is evidently an inconsistency innbsp;this as it is altogether probable that tbe impressions from the same horizon represent the foliage,nbsp;etc of the forms whose trunks were entombed at other localities under different conditions.

The shale at John Barr�s tunnel deserves careful examination, and additional collections should be made from it. Only one small bundlenbsp;of specimens was placed in my hands as coming from this locality, andnbsp;it contained at least one species not found elsewhere, while it givesnbsp;promise of well-preserved specimens from a critical horizon in the Lowernbsp;Cretaceous. Besides it is of a nature to preserve in great perfectionnbsp;the plants that it contains. Even in the apparently weathered fragments obtained the points were shown with a distinctness rarely found.nbsp;The shale is very fine-grained and fissile, splitting into thin and smoothnbsp;laminae.

1874. Zamites horealis Heer: K. Svensk. Vet.-Akad. Handl., Vol. XII, No. 6 (FI. Foss.

A Zamites, which is identical in all respects with Heer�s Z. horealis from the Kome beds of Greenland, is one of the most common fossils atnbsp;some of the localities yielding plants from the lower horizons of thenbsp;Hay Creek beds. It occurs on the horizon 150 feet above the Jurassic,nbsp;at John Barr�s tunnel, where it is the most common fossil, and appearsnbsp;to be abundant. On the horizon 50 feet above the Jurassic, it occurs alsonbsp;in carbonaceous shale; Webster�s ranch, where it is rather common, andnbsp;from which the specimen figured on PI. CLXII, Pig. 14, was obtained;nbsp;also at the shales over lowest coal, Larrabee�s shaft, where it is not sonbsp;common. The nerves were not seen, as they are probably immersed innbsp;the rather thick leaf substance.

This Zamites seems to me to be identical with that coming from the Kootanie beds and described by Sir William Dawson in his paper onnbsp;the Mesozoic floras of the Eocky Mountain region of Canada: Trans.nbsp;Eoy. Soc. Can., Sec. lY., Vol. Ill, p. 7, pi. i, fig. 5. This he has identified with Heer�s Z, acutipennis,� from the Lower Cretaceous of Greenland. This Zamites is evidently widely diffused in the Lower Cretaceous of Xorth America, and is highly characteristic of it. On thisnbsp;account, the entire absence in the Lower Potomac, of the type ofnbsp;Zamites to which it belongs is all the more noteworthy.

On the horizon 100 feet below the base of the Dakota sandstone, at the cliff on Oak Creek at Robbin�s ranch, a small fragment of a leaf wasnbsp;found, which looks like a portion of a Zamites. It has pretty strong,nbsp;closely placed, and numerous nerves. As it shows neither base nornbsp;termination, its character can not be determined. It may be Xageiopsisnbsp;or Podozamites. If it be a Zamites it does not belong to the type ofnbsp;Z. borealis Heer, but rather to that of Z. tenuinervis Pont., of thenbsp;Lower Potomac.

The above constitute all the occurrences of possibly cycadaceous foliage in the Hay Creek strata.

FONTAINE.] nbsp;nbsp;nbsp;LOWER CRETACEOUS FLORA.

G-enus G-LOSSOZAMITES Schimper. Glossozamites Eontaineanus Ward n. sp.

The most eommoo fossils are togmeef, �f detaobed leaflets a�d one ebtoe leaflet of J idant .eh.eli m strikiogly bte a Ne.iropferis of the

Coal Measares (IF. ��.��). I am pretty sure, however, that it is a Glossozainites, a form of cycad that hasi loafirri-r. i i .

-- r. � � r , nbsp;nbsp;nbsp;,.nbsp;nbsp;nbsp;nbsp;^�atiets which closely resemble

1 , nbsp;nbsp;nbsp;. � I. 1 T. 1nbsp;nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;^ Glossozamites, has leaf-

,s probably new. I wish that yon would eompare it with the flgures of Glossozamites in your library.^nbsp;nbsp;nbsp;nbsp;�

I^ol. XV, p. 271, pi. c.-sxxvi, fig. 12. nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;purvey,

,o:^/quot;;�!� nbsp;nbsp;nbsp;��I. aiiWike seed was tonnd on the horison

MO feet below the Dakota sandstone, at the cm on Oak Creel at Eobbln's Eanch. This b, ,al, respeet. is eaaetly like the � dtrnd bnbsp;the Lower Potomac of Virginia, and described under the name olcanbsp;deospermum rotundatum, in Mon. U. S. Geol. Survey Vol XV n 271'nbsp;A similar seed was found in the Trinity division of the Oomanche seriesnbsp;of the Lower Cretaceous of Texas. The Hay Creek seed has the shapenbsp;and size of G. rotundatum, with also its characteristic epidermis whiehnbsp;is smooth, parchment-like, and durable.nbsp;nbsp;nbsp;nbsp;�

21 have complied with me last suggestion in the above, which is contained in his repc small collection made by Professor Jenney and myself from the slope of Red Canyon, west of the foanbsp;sil forest containing these specimens. I have examined all the figures of Glossozamites and of thenbsp;forms originally referred to other genera (Podozamltes. Pterophyllum) that Schimper referred to thatnbsp;genns when he established it. The pinnules are generally more elongated and narrow, conforming to

lingulatis.�' This, however, has not been consistently adhered to. The figure that approache.s onri

most nearly is that of Kurr in his Beitrage z. loss. FI. d. Juraform. AVurttemburgs, 1845 pi. i fig 5 called by him Pterophyllum oUongifolium, and referred to Glossozamites by Schimpernbsp;In their short, rounded form they approach much more closely to some species ofOtozamites (cf. Onbsp;Beanii) (L. amp; H.) Brongn. in Saporta, Plantes Jnrassiques, Vol, II, pi, xcv, Fig. 2), and our Fig. 17 evennbsp;shows a slightly auriculate base. That genus passes in some of its species into Splienozamltes, innbsp;which the pinnules are wedge-shaped at the base, and either sessile or raised on a short stalk. Ournbsp;forms may he compared with S. latifolius (Brongn.) Sap. (of. op. cit., pi. cxiii, figs. 2, 3).

CRETACEOUS FORMATION OF THE BLACK HILLS.

WilliAMSONiA ? phcenioopsoides Ward ii. sp.^

PI. CLXII, Fig. 20.

An imperfectly preserved imprint of a portion of a plant was found on the horizon 150 feet above the Jurassic, at the cliff on the north sidenbsp;of the valley of the South Pork of Hay Creek. This, owing to itsnbsp;strong resemblance to Williamsonia, is placed doubtfully in that genus.

It consists of the summit of what seems to have been a thick, fleshy stem, from which radiate flabellately the basal portions of what werenbsp;probably thick, fleshy bracts, having the character of those of Williamsonia. The nature of these can not be made out, as only their basesnbsp;are preserved, and these seem to be distorted from compression bynbsp;crowding. This gives them less width than is shown in the bracts ofnbsp;most Williamsonias. The fossil looks something like a palm leaf, whichnbsp;preserves only the portion immediately around the summit of the petiole. It resembles, also, some of the forms of Jurassic Phcenicopsis,nbsp;which Heer has described in his PI. Poss. Arct., Vol. lY, Pt. IInbsp;(Beitriige zur Juraflora, Ostsib.), p. 112, pis. xxix, xxx, and it is notnbsp;impossible that it may belong to this genus. If it is a Williamsonia, itnbsp;is probably a new species.

Class CONIFERS (Conifers).quot;

Conifers form the most abundant plants in the Hay Greek strata. They surpass in species any other great group, and far exceed in thenbsp;number of individuals of some species any other plants. They are, asnbsp;a rule, the best pre.served specimens that are found at the severalnbsp;localities. While they are the most abundant forms in the highernbsp;strata, there is a noteworthy scarcity of them in the lower.

* Whatever may be the objections to giving names to defective objects, it is found in practice that to designate them merely �sp.� after assigning them even doubtfully to a genus leads to great confusion and involves much more labor on the part of all who may subsequently have anything to do withnbsp;them than to give them specific names. Such a designation is a name. It lias to be credited to thenbsp;namer, and the awkward combination thus produced becomes a permanent part of the synonomy.nbsp;But it involves the possibility that several different objects may have the same combination throughout. Some papers are so burdened with these names, falsely supposed to obviate the objection ofnbsp;nomina nuda or of undue definiteness, that it becomes necessary to number them and refer to themnbsp;as Nos. 1, 2, 3, etc., or even to count the lines on the page where the particular one in question isnbsp;mentioned and refer to them in this Avay. If tliey are not described they are nowiwa nuda, and ifnbsp;described they are names, and must be identified in some way. The evils of this practice have becomenbsp;so great that it might almost be given as a rule that if a form is Avorth mentioning at all it is Avorthnbsp;a specific name.

In view of the above I have given names to most such objects treated in this paper, and the name here employed is justified by Professor Fontaine's comparison of it with Heer's genus Phcenicopsis.

21 have not attempted in this paper to classify the Coniferae according to the latest systems, but have left the arrangement substantially as Professor Fontaine drew it up. The forms enumerated,nbsp;however, embrace not only the families Taxace� and Pinace� hut also the class G-inkgoales.

A number of cone scales and seeds were found in the lower strata of the Hay Greek Lower Cretaceous series which seem to belong to a newnbsp;species of conifer closely resembling Araucaria. The fossils occur asnbsp;cone scales and seeds on the horizon 150 feet above the Jurassic, at thenbsp;clilf on the north side of the valley of the South Fork of Hay Creek.nbsp;A cone scale (PI. OLXIII, Fig. 7) was discovered with traces of a seednbsp;on it at the contact of the Cretaceous with the Jurassic, at the bednbsp;of shales Lon Cottles�s ranch; also a number of detached seeds (PI.nbsp;CLXIII Figs. 1-�, 8, 9). Some seeds attached to scales and somenbsp;scales without seeds were found. These fossils form pretty much allnbsp;that were obtained from this locality. Some of the seeds and scalesnbsp;are remarkably well preserved, and show very well the relation of thenbsp;seeds to the scales, as well as the form of the latter. The scales, likenbsp;those of the true Araucaria, were evidently very deciduous, for nonbsp;indication was found of their attachment to an axis. Both the seedsnbsp;and the scales vary a little in shape, which is no doubt due to distortion from pressure. The seeds are hard and bony or nut-like in structure and have an ovate-euneate to nearly cuneate form. They are 4 tonbsp;5 mm. long, and have a width of 3 to 3.5 min. in their widest portion.nbsp;The forms of these seeds, differing somewhat in shape, are given on PI.,nbsp;CLXIII, Figs. 1-9. Pig. 1 (enlarged 2 diameters in Fig. 2) gives thenbsp;most common and normal form. This seed shows on its margin a remnant of the cone scale to which it was once attached. Pig. 3 (enlargednbsp;2 diameters in Fig. 4) shows a seed somewhat larger and narrower thannbsp;that given in Pig. 1. Fig.J (enlarged 2 diameters in Fig. 6) gives a shapenbsp;that is more ovate than the normal, more enlongated, and narrowernbsp;proportionally than common. This shape nears that of Carpolithusnbsp;fwnarius, described below, and suggests the idea that this latter maynbsp;be an abnormal form of the Araucarites now being described. Thesenbsp;�variations are most probably due to distortion from pressure.

The cone scales are strikingly like those of Araucaria. They are broadly cuneate in outline, and leaving out their terminal part, are notnbsp;unlike the seeds borne on them. In their widest portion tliey are aboutnbsp;9 mm. wide. Including their beak-like tips, they have a length of aboutnbsp;12mm. Their free ends or summits are thickened and carry a beak likenbsp;projection, as in Araucaria. They show, as might be expected, morenbsp;distortion from pressure than do the seeds. They were apparentlynbsp;leathery, firm texture, and very durable. Fig. 7 shows a cone scalenbsp;that has indications of the thickening at its summit. Fig. 8 (enlargednbsp;2 diameters in Fig. 9) gives the most complete and undistorted scale-found. It has a seed partly embedded in its surface, and this embed

diug of the seed in the inner surface of the scale appears to have been the normal mode of attachment of the seed to the cone scale. Judgingnbsp;from this specimen the seeds were borne singly under each scale, embedded in its inner surface. They were flattened, and in shape resembled the scale to which they were attached. These features remind onenbsp;strongly of the cones of Araucaria Ciinmngliamii Alton, the Moretonnbsp;Bay pine, which contains similar seeds in the same way in its cone scales.

This is a single cone scale found at John Barr�s tunnel, on the horizon 150 feet above the top of the Jurassic. It is too poorly preserved and there is too little material to enable one to fix the character. It is,nbsp;however, a cone scale of some Arauoarites, and it is clearly a diiferentnbsp;species from Araucarites wyomingensis, for it is much longer than anynbsp;of the cone scales of that jilaut, and it tapers more gradually. It isnbsp;spatulate-cuueate in forni, rounded at the free end, and widest here,nbsp;having the width of 9 mm. in this iiortion. It is 2 cm. long and tapersnbsp;very gradually to the end by which it was attached, where it shows anbsp;width of 2 mm. It shows no trace of a beak at the free end, and nonenbsp;of a seed, as it has evidently suffered from maceration.

1883. Finns smquaensis Dn.; Trans. Roy. Soc. Can., Sec. IV, Vol. I, p. 23, pi. iii, fig. 36.

Sir William Dawson, in his paper on the Cretaceous and Tertiary Floras of British Columbia and the Northwest Territory (1883) and onnbsp;the Mesozoic Floras of the llocky Mountain Kegions of Canada (1885),nbsp;p. 9, pi. ii, figs. 6, Ga, has described very narrow and long Pinus leaves,nbsp;which he has named P. siisquaensis. Fragments of precisely similarnbsp;leaves occur mostly in the lower strata of the Hay Creek Lower Cretaceous. This gives another connecting link with the Kootanie flora.nbsp;The specimens found in the Hay Creek beds are much more imperfectnbsp;than those described by Sir William Dawson. They are never foundnbsp;entire or grouped, but are fragments sufficient to show that they mustnbsp;have been quite long. Their fragmentary and scattered condition indicate that they must have drifted some distance. It is not always easynbsp;to distinguish leaves like these from those of Leptostrobtis longifolius,nbsp;which they much resemble, especially when no nerves are visible. Thenbsp;possession of a midnerve, when this is visible, is decisive. Otherwisenbsp;the decidedly greater thickness and rigidity of the Pinus leaves points

* Professor Pontaiiie did not give this a specific name, and I have supplied it on the principle stated in the last footnote. It is perhaps better than to reject it altogether.

to their presence. The Hay Greek leaves are one-nerved, about 1 mm. wide, quite thick and rigid. They occur ou the horizon 100 feet belownbsp;the Dakota sandstone, in small bits, which are rather rare and ofnbsp;doubtful character. They may be leaves of Leptostrobus, which bynbsp;wrinkling from pressure, appear to have a midnerve. The localitynbsp;showing these doubtful forms is the cliff on the north side of Pinenbsp;Creek, where a multitude of Leptostrobus leaves occur with them.

On the horizon 150 feet above the Jurassic, at the shales under the third sandstone, Barrett, it is more certainly shown; still, however, innbsp;rather rare and small fragments. These are thick in texture, one-nerved,nbsp;and rigid. On the horizon 50 feet above the Jurassic, at the carbonaceous shales, Webster�s ranch, it is quite common in pretty large, wellnbsp;characterized fragments.

The specimen figured �n PI. OLXIII, Fig. 11a is from the clilf on the east bank of Oak Greek; that in Fig. 12 is from the shales under thenbsp;third sandstone above the coal at Barrett, and the large leaves shownnbsp;in Fig. 13 are from the cliff on the east bank of Oak Creek, 2 miles belownbsp;Bobbin�s ranch.

1889. AMetites angusticarpus Font.: Potoma� Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 263, pi. cxxxiii, flg. 1.

A specimen of a narrow cone was found ou the horizon CO feet below the Dakota sandstone, at the cliff' in the east bank of Oak Creek.nbsp;This is apparently identical in species with the cone of a similar character found in the Lower Potomac of Virginia and described asnbsp;AMetites angustiearpus in Mon. IJ. S. Geol. Survey, Vol, XV, p. 263,nbsp;pi. cxxxiii, fig. 1. It has the same form quot;with the Potomac plant andnbsp;the same kind of cone scales, which, in their lower portions at least,nbsp;are thin and at the same time are closely imbricated.

1889. Leptostrobus lougifolius Font.; Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 228, pi. ci, figs. 2, 3; pi. cii, figs. 1-4; pi, ciii, figs. 6, 6a-e, 7, 7a, 8,nbsp;8a, 9, 10, 10a, 11, 12; pi. civ, fig. 6.

This species, described by the writer from the Lower Potomae of Virginia in Mon. U. S. Geol. Survey, Vol. XV, pp. 228-230, is one ofnbsp;the most common plants in Professor Jenney�s division No. 2, of thenbsp;Hay Creek beds. Hardly a specimen at some localities is found without imprints of fragments of the leaves, and on some fragments of

rocks they are jiiled upon one another. It is not found at all below the horizon 100 feet beneath the Dakota sandstone. With only one xiroba-ble exception the leaves are found unattached to a stem. They occurnbsp;mostly as scattered fragments and show neither base nor summit. Innbsp;cases where the specimens are very numerous and lie one upon anothernbsp;there is no means of determining the original length of the leaves.nbsp;They must, however, have been very long, for some of the fragmentsnbsp;are 8 cm. long. The texture was thin, a good deal thinner than thatnbsp;of the leaves of Pinus. This thinness of texture and the absence of anbsp;midnerve are the most obvious differences between this plant and Pinus.

This plant occurs on the horizon 100 feet below the Dakota sandstone at the cliff on the north side of Pine Creek, which furnished thenbsp;specimens figured on PL CLXIII, Fig. 15, and PI. CLXV, Fig. 3.nbsp;Here it is the most common plant, scattered leaves occuring on nearlynbsp;all the specimens, while on some they are piled up or matted together.nbsp;They occur more rarely on the same horizon, at the cliff' on Oak Creek,nbsp;at Eobbin�s ranch. On the horizon 00 feet below the Dakota, at thenbsp;cliff on the east bank of Oak Greek, they are found also, but not verynbsp;abundantly. The leaves are mostly 1 mm. wide, rarely attaining thenbsp;width of 1.5 mm. Most of the best preserved imprints show, with thenbsp;help of a good lens, a varying number of fine parallel nerves, lookingnbsp;like striiE, up to the number of 0, which is probably the true number.nbsp;Some, however, of the exceptionally well preserved imprints with thenbsp;same helj) disclose two comparatively strong parallel nerves, one nearnbsp;each margin with a flat space between, in which fine nerves like thosenbsp;shown on most of the leaves are visible up to about 4 in number. Heernbsp;in FI. Foss. Arct., Yol. VI, Abth. I, Pt. I (Xachtriige zur Jurafloranbsp;Sibiriens) p. 25, has given these last-named characters for some of thenbsp;leaves of bis Leptostrobus rigida. The character given by Heer wasnbsp;not seen in any of the leaves of the Lower Potomac of Virginia, nonbsp;doubt because none of these were as well preserved as are some ofnbsp;the Hay Creek specimens. The fact that some only of the Hay Creeknbsp;leaves show the two stronger nerves seems to indicate that these arenbsp;visible as such�that is, as prominent veins�only on the under side ofnbsp;the leaves, whereas on the upper side, if seen at all, they appear asnbsp;fine nerves. On some of the best preserved imprints, with the help ofnbsp;a lens, these stronger nerves appear to be formed by the close approximation or consolidation of several fine nerves.

One of the specimens from the cliff on the north side of Pine Creek shows a great number of leaf fragments, and among them a number converging so as to appear to form or be attached to a short twig. This is anbsp;feature seen in some of the Lower Potomac specimens. From the greatnbsp;number of leaf fragments in some cases, and from the almost totalnbsp;absence of attachments of these, they must have been quite deciduous.nbsp;From the additional facts found in the Hay Creek specimens we maynbsp;amend the description of the species given in Mon. IJ. S. Geol. Survey,

Vol. as follows: Leaves tbiii in texture, showing on the upper surface, with the help of a lens, line parallel nerves up to 6 in number; oil the under surface 2 stronger parallel veins and between them finenbsp;nerves up to 4 in number.

It seems to the writer that some Lower Cretaceous plants described under other names should be identified with this species. Heer hasnbsp;described as Pinun Fetcrseni in FI. Foss. Arct., Vol. I, Kreideflora, p. 84,nbsp;pi. xliv, fig. 19, a, b, leaves which he gives as being thin in texture,nbsp;about 1 mm. in width, although in fragments showing considerablenbsp;length and having several nerves�in a word, as having most, if notnbsp;all, of the characteristic features of Leptostrohus longifolius. Thisnbsp;plant, coming from the Koine beds of Greenland, is most probablynbsp;LeptostrobiiH longifolim. fleer gives as OzehanowsMa dicJiotoma, alsonbsp;from the Koine beds, leaves which he describes in Fl. Foss. Arct., Vol.nbsp;VI, Abth. 11, Flora der Komeschichten, p. 14, pi. ii, fig. 12b, pi. iii, fig.nbsp;1, and which he identifies with his Selerophyllina dichotoma. It, however, in its leaves appears a more delicate plant than 8. dichotoma, andnbsp;with narrower forms. The leaves do not appear to fork at all, thenbsp;apparent forking, as given by Heer, being due to the fact that the endsnbsp;of some ot the apparent branches, really independent leaves, are hidden by the other superposed leaves. The leaves of this specimen arenbsp;exactly like those of Leptostrobns longifolius in their general characternbsp;and their arrangement on the stem, as shown in fleer�s pi. iii, fig, 1,nbsp;and much like some of the forms of this species shown in the Potomacnbsp;specimens, for example, those in pi. cii, figs. 1, 2, of the Potomac flora.

PI. cLxnr, Pigs. 16,17.

A small winged seed was found on the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pine Creek. Ifcnbsp;reminds one of the winged seed obtained from the Brown Jura andnbsp;assigned by Heer to Leptostrobns (see Fl. Foss. Arct., Vol. VI, Abth.nbsp;I, Pt. I, Kachtriige zur Juraflora Sibirieus, p, 23). The seed now innbsp;question is about 4 mm. long and less than 2 mm. in width. It isnbsp;elliptical in shape and appears to retain only a portion of the wingnbsp;showing on the left-hand upper portion a part of it in the form of annbsp;elliptical projection like a beak. The seed is entire, but the appendagenbsp;is too poorly preserved to give any reliable indication of its true character. Its true position is quite doubtful, but it may provisionally, andnbsp;for the sake of a name, be placed with Leptostrobns. Peptostrobusnbsp;longifolius is the most common fossil at this locality.

� No apeoifio name was given by Professor Fontaine to this seed. I have therefore empUed the leading character in a-ssigning it a name.

1889. Athrotaxopsis tenuicauUs Font.: Potoniiic Flora, Mon. II. S. Geol. Survey, Vol. XV, p. 241, pi. cxiv, figs. 4, 4a, 5; pi. cxv, ligs. 4, 4a; pi. cxvi, fig. 6; pi. cxvii,nbsp;figs. 2, 2a.

In Professor Jeimey�s division Xo. 2 of tlie Hay Creek beds are found some specimens of a conifer tliat agree well with Athrotaxopsis tenuicauUs as described by the writer, from the Lower Potomac of Virginia,nbsp;in Mon. �. S. Geol. Survey, Vol. XV, p. 241. The fossils are in the formnbsp;of fragments of alternate twigs of varying length, as shown on PI.nbsp;CLXIV, Pigs. 1-3. The thickness of these will, on an average, somewhat surpass the average of the Potomac Athrotaxopsis tenuicauUs andnbsp;will lie between it and that of A. grandis. This, however, does notnbsp;seem to indicate a new species, but rather a more vigorous habit ofnbsp;growth for the Hay Creek xilaiits, a feature shown also in the Sequoianbsp;Reichenbachi, from these strata. In the Hay Creek beds Athrotaxopsis tenuicauUs occurs on the horizon 100 feet below the Dakota sandstone rather commonly, but in small fragments at the cliff on the northnbsp;side of Pine Creek. On the horizon 60 feet below the Dakota sandstone it occurs not very commonly, but in well-iireserved large twigsnbsp;at the cliff in the east bank of Oak Creek, from which all the sxieci-niens here figured were obtaiued. One of the sj)ecimeiis bears a cone,nbsp;represented by Pig. 4 of the same xilate.

1842. Araucaj-ites Jteichenbachi Geiu.; Characteristik d. Schichten u. Petrefacten d.

1849. Araucaria lieiehenbachi (Gein.) Debey: Entwurf. z. einer geogn.-geogenet. Dar-stellung d. Gegend v. A.achen, pp. 63, 64 (Nachtriige).

1868. Sequoia IteiclienbacJii (Gein.) Heer: FI. Foss. Arct., Vol. I, p. 83, pi. xliii, figs. Id, 2b, 5a, 5d, 5dd, 8, 8b. �

Fine leafy branches of a Sequoia, having all the characters of 8. Reichenbachi, occur at the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pine Creek, along with the conesnbsp;that probably belong to the same species.

At the horizon 60 feet below the Dakota sandstone, at the cliff in the east bank of Oak Creek, several cones of a similar kind are found.nbsp;These latter are poorly jireserved, but they retain character enough tonbsp;justify identifying them with cones of 8. Reichenbachi.

' The synoiioray here given ia only partial, as a complete one would involve the decision of a num-bei of knotty questions, for which this is obviously not the place. The only omission that concerns us here is that of Geinitzia cretacea Eudl., which will be considered a little later.

The flue, leafy twigs distinguished by Professor Jenuey as specimens A and B are the most complete of the leafy branches. The largest ofnbsp;these, specimen A, shows a portion of an ultimate twig that is 15 cm.nbsp;long and 3 mm. wide. It has a number of the characteristic curvingnbsp;leaves of 8. Reichenhachi, which are widest at base and narrow at theirnbsp;ends to an acute tip. The longest of these were 16 em. in length. Thenbsp;leaves that are retained are attached laterally. The upper face of thenbsp;twigs show occasional elongate elliptieal scars left by the bases of thenbsp;leaves that have fallen off.

The slab marked B by Professor Jenney has been photographed and forms PI. CLXV. Fig. 1, on the left, shows the leafy branch abovenbsp;mentioned, while Fig. 2, on the lower right, is the imprint of a smallnbsp;cone which may have belonged to the same branch or individual. Allnbsp;across the slab lie the long two-nerved leaves of Leptostrobus longi-foUus Font. (Fig. 3). This specimen is from the cliff on the north side ofnbsp;Pine Creek, 100 feet below the Dakota sandstone in division No. 2 ofnbsp;Professor Jenney.

The fine cone given in PI. OLXVI, Fig. 1, comes from the same horizon and locality. It is almost certainly the cone of S. Reichetibachi,nbsp;for it has attached to it a portion ot the twig on whose summit thenbsp;cone was borne, and this has elliptical scars like those seen on thenbsp;upper surface ot leafy branches of S. Reichenbachi. Besides, it agreesnbsp;very well with the cones griven by Heer for this species in FI. Foss.nbsp;Arct., Xol. Ill, PC II (Hie Kreide-Flora des Arctischen Zone) pi. xx,nbsp;figs, la, 2, 3. The cone scales are, however, longer than those of Heer,nbsp;probably on account of differences in the mode of preservation. Thosenbsp;of Heer seem to be compressed vertically, while in the Hay Creeknbsp;specimens they may be elongated by pressure.

These cones are comparatively large for those of a Cretaceous Sequoia. With the scales closed, this one was probably broadly elliptical in shape, having a length of 30-35 mm. and a maximum thickness of 20-25 mm.

1874. Sequoia i/racilis Heer: Die Kreide-Flora des Arctischen Zone, K. Sveusk. vet.-Akad., Handl., Vol. Xn, No. 6 (FI. Foss. Arct., Vol. Ill, Pt. II), p. 80, pi. xviii, flg. Ic; pl. xxii, figs, la, lb, Ic, 2-1, 5a-e, 7, 8, 8b, 9, 10, 10b, 10c.

Small, round cones of a Sequoia occur sparingly on the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pinenbsp;Creek and at the cliff on the south side of Pine Creek. The specimensnbsp;here figured were obtained at the latter locality. These cones arenbsp;evidently of a different species from those that occur with them, andnbsp;which I have identified with Sequoia Reichenbachi, They are muchnbsp;smaller, and are round in shape. One of them is depicted in Fig. 2, PI.nbsp;CLXYI. They have not been found attached to any leafy branches,nbsp;hence the character of the leaves with which they belong can not be

determined. In size, shape, indeed in all features, they agree well with the cones that Heer determines as those of 8. gracilis, and whichnbsp;he depicts in FI. Foss. Arct., Vol. Ill, Pt. II, pi. xxii, figs. 5a, 5h, 5d.

Leafy branches of Sequoia gracilis have not been identified by the writer from the Hay Creek strata, but the plant identified with Spheno-lepidium parceramosum is not uncommon in the strata containing thenbsp;cones now in question. The leaves and twigs of this are so much likenbsp;those of 8. gracilis that I would not hesitate to identify these Hay Creeknbsp;fossils with it were it not that the leaves contain a midrib, whereasnbsp;Heer says those of 8. gracilis are without it.

An immature cone of some Sequoia was obtained on the horizon 150 feet above the Jurassic, at the cliff on the north side of the valley ofnbsp;the South Fork of Hay Creek. It is 8 mm. long, 6 mm. wide, and nearlynbsp;globular in form. On its surface it shows, rather vaguely, rhombicnbsp;imprints of the character of those made by the terminations of Sequoianbsp;cone scales. There is nothing to show with what leafy branches itnbsp;belongs. It is shown natural size on. PI. CLXVI, Fig. 3, and enlargednbsp;two diameters in Fig. 4.

Certain remarkable imprints of the stems of a conifer, which seems to be a new species of the genus Geinitzia, are found in Professornbsp;Jenuey�s division Xo. 2 of the Hay Creek beds. They occur in smallernbsp;specimens on the horizon 100 feet below the Dakota sandstone, at thenbsp;eliff on the north side of Pine Creek (PI. CLXVI, Pigs. 5-11), andnbsp;on the horizon 60 feet below the Dakota, at the cliff iii the east banknbsp;of Oak Creek, in larger ones (PI. CLXVII). The stems leaving thenbsp;imprints were fragments of much larger parts, for they are broken atnbsp;both ends and show no appreciable change in thickness from one endnbsp;to the other. In no case was any of the vegetable matter of the stemnbsp;or leaf preserved, but all the fossils are in the form of flattened moldsnbsp;of the stem. The molds on their inner surface bear imiirints in the

' This genus -was founded by Endlicher in bis Synopsis Coniferarurn, 1847, p. 280, to include certain forms referred by Geiiiitz to Sedites and Araucarites and by Corda to Cryptomeria. Among the former was the AraucaHtes lleichenbachi of Geinitz, which Heer in 1808 identified with the living genusnbsp;Sequoia, of which Endlicher was also the author. Since the latter date this well-known fossil plantnbsp;has been almost uniformly called Sequoia Reichenbachi^ and many place Endlicher�s Geinitzia cretaceanbsp;under it as a synonym. Others retain the older forms under Geinitzia, and this has been done by Professor Eontaine, while still recognizing Sequoia Reichenhachi. It will be allowed to stand thus,nbsp;although it seems to me that the retention of the genus Geinitzia logically carries the S. lleichenbachinbsp;with it into that genus as the type, while, on the other hand, the recognition of S. Reichenhachi logically abolishes the genus Geinitzia.

inclosing shale, which are the reverse of the markings shown on the surface of the stem. The molds are so flattened by pressure that theynbsp;are almost completely collapsed. In splitting the shale the cleavagenbsp;took place along these collapsed molds, so that the imprint on thenbsp;specimen shows the inner surface of more or less than one-half of thenbsp;mold. In some of the imprints both margins of the half mold are morenbsp;or less xgt;reserved, so that the original width may be detected, and innbsp;some jdaces a narrow portion ot the other half, next to the margin, isnbsp;obtained, so that one can get an idea of the thickness of the stem afternbsp;its flattening. When we take into consideration the considerablenbsp;thickness of some of the stems, as indicated by the width, the amountnbsp;of compression is surprising. Molds having a width of 1.5 mm. show anbsp;hollow only 2 to 3 mm. thick. This indicates that comj)aratively oldnbsp;branches were still soft and succulent. On one of these flattened moldsnbsp;may be seen imprints of short jjortions of the basal jiarts of a numbernbsp;of leaves. These leaves were a portion of those attached to the stemnbsp;on the parts that, in the crushing, formed the margins of the collaj^sednbsp;molds, and hence were in the most favorable position to be preserved.

The stems.�In describing the stems I will give first the character of the imprints in the shale, and then from these deduce the nature of thenbsp;markings on the stem that made them.

The smallest imprint seen of what seems to be a series of stems of the same xdant, and the one here named Geinitzia Jenneyi, is thatnbsp;depicted in Fig. 5 of PI. CLXVI enlarged two diameters in Fig. (1. Itnbsp;is 35 mm. long and 4 mm. wide, being made by a fragment of whatnbsp;was originally a much longer stem. If it belongs to the same plantnbsp;with that making the impressions to be described further on, thennbsp;it is the youngest of the series. The imprints of the leaf scars havenbsp;considerable interspaces, but still are pi�ctty thickly set on the imprintnbsp;of the stem. They are rhombic in form, with the greater dimensionsnbsp;in the direction of the axis of the stem. Their lateral angles arenbsp;more or less rounded off'. The superior angle is acute and the inferiornbsp;one similar in form, but this latter is generally not defined wellnbsp;enough to be seen. Toward the upper part of the imprint there is anbsp;vague indication, on the best preserved imprints, of a furrow running in the direction of the axis of the stem, with a pit, as if made bynbsp;the .entrance of the vascular bundle of the leaf. If these imimints werenbsp;stretched at right angles to the axis ot the stem, which would occur innbsp;the case that they are made by permanent leaf scars on stems thatnbsp;increase in thickness, they would graduate in shape into the formsnbsp;represented on PI. CLXVII, Figs. 1, 2.

PI. OLXVII, lig. 1, dexjicts the largest and most complete imprint found. It was evidently made by a stem that was much larger andnbsp;longer than that making the imprint given in Pig. 5 of PI. OLXVI,nbsp;and api^areutly was corresxtondingly older. That it is a fragment of anbsp;much longer stem is shown by the fact that it is broken short off' atnbsp;both ends, and, although 16 cm. long, shows, from one end to the other.

no appreciable deviation from a width of 15 mm. This is the imprint that shows traces of leaves along the margins. This imprint is thicklynbsp;set with deimessions made by leaf scars. These imprints of leaf scarsnbsp;are more closely placed and much larger and more distinct than thosenbsp;of PI. CLXVI, Fig. 5. With the increased thickness of the stem, thenbsp;leaf scars seem to have had their dimensions at right angles with thenbsp;stem increased more than those in the direction of the axis.

The imprints of the leaf scars shown on this specimen are deep and vgry distinct. In contour they are approximately rhombic, with thenbsp;transverse dimensions slightly greater than those in the direction ofnbsp;the length of the stem. The upper margin, however, is a curve, andnbsp;the lower one shows a more or less obtuse angle. The right and leftnbsp;ends, or lateral angles, are acute and more or less drawn out into pointsnbsp;that are directed downward, as shown in Fig. 2 of PI. GLXVII, whichnbsp;represents an enlarged and restored imprint. Within the depressednbsp;area forming the imprint of the leaf scar there is a boss or proturber-ance, more or less elliptical in shape, with its major axis at right anglesnbsp;with the axis of the stem. This boss is often distorted by pressure, andnbsp;varies then somewhat in shape, being sometimes even round. The bossnbsp;is bounded by a depressed line or furrow that is slightly deeper thannbsp;the rest of the imprint. From the right and left ends of the furrow anbsp;similar furrow, one on each side, in perfectly formed imprints, runsnbsp;toward the lateral angles of the imprint of the leaf scars. But thesenbsp;are rarely seen. The boss is jdaced, not centrally, but somewhat nearernbsp;the angle of the lower margin of the imprint of the leaf scar. As indicated in the best preserved imprints, the original and normal shape ofnbsp;the boss and of the furrow which bounds it and determines its formnbsp;wasapproximately that of the entire imprint�that is, rhombic�but withnbsp;the difference that the lower angle, instead of the upper, is roundednbsp;out more or less into a curve. However, as stated, distortion usuallynbsp;destroys this form. There are sometimes indications that the centralnbsp;portion of the boss was raised into a sort of mamma or teat.

The imprint given in Fig. 8 of PI. CLXVI seems to have been made by a stem older and larger than that depicted on PI. CLXVII. Itsnbsp;width is about 15 mm., but one margin is not preserved, so that thenbsp;imprint does not show the true size of the stem. The imprints of thenbsp;leaf scars here are larger and more crowded than in the form represented on PI. CLXVII, Fig. 1. Owing to their crowding, their uppernbsp;margin no longer shows the curvature seen in that figure, but tends tonbsp;become angular, giving the contour more truly a rhombic shape. Thenbsp;lateral angles are more rounded off, and the lower angle is prolonged tonbsp;form a kind of tail, as represented in Fig. 9 of PI. CLXVI. Betweennbsp;these imprints of scars there are no interspaces, as were still to be seennbsp;on the specimen figured on PI. CLXVII, but they crowd one another.nbsp;The stem, whose imprint is depicted in Fig. 8 of PI. CLXVI, must havenbsp;been larger than that figured on PI. CLXVII, for it shows a width ofnbsp;15 mm., with only one margin preserved. The amount of woody matter

iu the stem.s making the imprints must have been small, for in the specimens enough of the mold is shown to indicate that it was flattened to a thickness of only 3 or 3 mm. This leads us to infer that these imprintsnbsp;could not have been made by cones, and that if by stems they mustnbsp;have remained succulent a long time.

The imprint depicted in Fig. 10 of PI. CLXVI, if not larger than that represented by Fig. 8, seems to have been older. As one margin ofnbsp;the imprint is not shown, we can not determine the true size of the stern.nbsp;The imprint of the stem in this case is rather more than 15 mm, wide.nbsp;The imprints of the leaf scars are larger, more crowded, and more distinct than those of any of the previously described specimens. In then-shape they show still further modification. The upper margin is morenbsp;decidedly angular, the tail from the lower angle is nearly or quite obliterated and the impi�ints are more elongated transversely. The scarnbsp;imprints have here more ot the true rhombic form than any of thosenbsp;described in the preceding pages. The imprints are deep and very distinct. The central protuberance is more distinct than any of the others,nbsp;and the furrows running from its right and left ends to the lateral anglesnbsp;of the imprint of the leaf scar are deeper and more sharply defined thannbsp;in any others.

The imprints described in the preceding account are seen in the rock material that surrounded and entombed the original stems. Thej^ arenbsp;markings imprinted on the inner surfaces of the collapsed molds, andnbsp;of course in character they are the reverse markings on the stemsnbsp;which imprinted them. Convexities on the surface of the stems formnbsp;concavities in the surrounding sediment, and, vice versa, concavitiesnbsp;correspond to convexities. It may be concluded, then, that the stemsnbsp;forming these fossils had on their surface prominences or cushionsnbsp;approximately of rhombic form, but varying in the manner describednbsp;with the age and thickness of the stem. These had within their margins a rim or ridge, also approximately rhombic in form, and thisnbsp;inclosed a depressed, transversely elongated area which contained anbsp;circular, still deeper depression, which was caused by the entrance ofnbsp;the vascular bundle from the leaf into the stem. From the lateralnbsp;angles of the central ridge inclosing the depression there passed, onenbsp;on each side, a raised line or ridge to the lateral angles of the leaf scar.nbsp;These cushions seem to have been permanent, and they were probablynbsp;left by the disartieulation of the leaf bases from the stems, like thenbsp;scars of Lepidodendron, which they resemble in form. They seem tonbsp;have grown in size with the increasing thickness of the stem whichnbsp;bore them and to have become more crowded and pronounced iu character, A comparison of the imprints depicted in the figures given innbsp;the preceding seems to show that they were made by stems belongingnbsp;to the same species, and that the differences in their forms are causednbsp;by the fact that the scars in enlarging with age increased more in theirnbsp;dimensions at right angles to the axis of the stems than iu the direction of that axis. At the same time they became more crowded.

The leaves.�Unfortunately, no imprints of entire leaves were seen attached to the fossils. On the margins of the imprints given on PI.nbsp;CLXVII there may be seen imprints of small ijortions of the lowestnbsp;parts of a number of leaves. These imprints indicate that the leavesnbsp;that made them are narrow, curved upward, keeled, pretty tliick atnbsp;their bases, and very rigid. In fact the imprints are such as would benbsp;made by leaves similar to those which Velenovsky gives as those ofnbsp;Geinitzia cretacea, and which he has figured and described in Die Gym-nospermen der b�hm. Kreideformation, p. 15, pi. viii, figs. 11,12; pi. ix,nbsp;figs. 1,2. The leaves referred to are given in pi. ix, fig. 1.

At first sight the imprints of the leaf scars look, in their general form, like Brachyphyllum, but the leaves of that genus have a boss in theirnbsp;center instead of a pit. The other markings also are too regular fornbsp;those of B rachyphylluin, and are not of the same pattern. The imprintsnbsp;are strikingly like those made by the terminal surfaces of the cone scalesnbsp;of some Pinus, but to make them the scales must have stood at rightnbsp;angles with tiie axis of the cones. This is true of the cones of Geinitzia,nbsp;which are also long and cylindrical. But the markings on the terminalnbsp;surfaces of the cone scales of Geinitzia are totally different. Besidesnbsp;it would seem impossible to compress any cone into the thinness indicated by the molds, especially cones with scales at right angles to thenbsp;axis. The forms represented in Fig. 5 of PI. CLXVI and bn PI.nbsp;GLXVII are obviously imjmssible for cones. Those given in Figs. 8nbsp;and 10 of PI. OLXVI might more probably pass for imprints of cones,nbsp;but they are clearly made by portions of long cylindrical bodies, toonbsp;long for cones. Then, too, the impressions on these are clearly essentially the same in character as those on PI. CLXVII. The impressionsnbsp;made by the leaf scars in these stems are so strikingly like those shownnbsp;on fig. 1, pi. ix, of Velenovskj'^, referred to above, that we can not resistnbsp;the belief that if not of the same genus they must be closely allied tonbsp;it. The resemblance between Velenovsk.Cs fig. 1 and Fig. 1 of PI.nbsp;CLXVII is essentially strong, extending not only to the shape of thenbsp;imprints of the leaf scars, but also to the depression within it. Thenbsp;same gradation in shape is also indicated. The jmunger branches ofnbsp;Geinitzia cretacea, as given in pi. ix, fig. 2, of Velenovsky�s work, havenbsp;the rhombic imprints with the greater dimensions in the direction ofnbsp;the axis of the stem, as in Fig. 5 of PI. CLXVI. Another fact thatnbsp;indicates that our xdant is nearly allied to that of Velenovsky is thenbsp;number, xrersisteuce, and distinctness of the imprints of the leaf scars.nbsp;I know of no conifer except Geinitzia that shows these features. Heer�snbsp;Geinitzia formo.m shows crowded, persistent rhombic leaf scars.

Lesquereux, in his Tertiary Flora, pi. Ixi, figs. 28, 29, represents stems with crowded, xjersistent scars of what he calls Sequoia longifolia. Onnbsp;jd. Ixii, figs. 15-18, he gives representations of stems with similar scars,nbsp;which he calls Sequoia Mformis. These scars closely resemble those onnbsp;our PI. CLXVI, Fig, 5. On x)l. vii, in fig. 19, he gives a similarlynbsp;marked stem for AMetites duhvus. All of these plants Schenk states he

regards as Geinitzia. See Zittel�s Haudbuch der Paljeontologie, Abtb. II, pp. 299-300. On pb vii, of the above-cited work of Lesquereux, innbsp;fig. 31, there is a representation of a stem of what he regards as Finnsnbsp;pala�ostrohus (Ett.) Heer. The scars on this are strikingly like thosenbsp;on the older stems of the Hay Creek plant.

The resemblance between the Hay Creek forms and Geinitzia is so strong that we are justified in placing them in that genus, at least provisionally. As Geinitzia is hitherto known from no strata older thannbsp;the Younger Cretaceous, it may be found that our jdant is an ancestralnbsp;form of the true Geinitzia. In that case it would be fittingly named

1846. Thuifes (�uiyressUesl') /iumaniisBunk.: Moiiographie d. norddeutsch. Weaiden-bildung, p- 20, pi. rii, fig. 8.

1846. nbsp;nbsp;nbsp;Lycopodites f sp. Dunk.: Op. cit., pp. 20,8.5, pi. viii, fig. 8.

1847. nbsp;nbsp;nbsp;Widdringtonites hurrianus (Dunk.) End!.; Synopsis Coiiiferarum, p. 272.

1852. JViddrim/lonites Haidingeri Ett.; Reitrag Flora d. Weaklenperioile, Abb d k. k. geol. Keichsanst., Vol. I, Abtb. ,3, No. 2, p. 26, pi. ii, fig. 1,

1852. AraucarUes Dunlceri Ett., in pt.: Op. cit., p. 27, pi. ii, fig. 10 (non figs. 2-9).

1870. nbsp;nbsp;nbsp;fJraucarites hamatus Trantsob.; Der Klin�scbo Sandstein, Nouv. M�m. Soc.

Imp. de Moscou, Vol. XIII, p. 225 (Livraisou 3, p. 37), pi. xxi, figs. 3, 3a, 3b, 3c.

1871. nbsp;nbsp;nbsp;Spheiioleins Kurriana (Dunk.) Schenk: Foss. FI. d. uordwestdeutsoh. w�ealden-

formation, Palaeontograpbica, Vol. XIX, p. 243, pi. xsxvii, figs. 5-8 8a-pi. xxxviii, fig. 1 (non tig. 2), nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;�

1881. Sphenolepidium Kurrianum (Dunk.) Heer: Contr. ala FI. Foss, du Portno-al Section des Travaux geologiques du Portugal, p. 19, jfi. xii, fig. ib; pi. xiii�nbsp;figs, lb, 8b; pi. xxi, fig. 5c; pi. xviii, figs. 1-8 (excl. figs. 5b, 5c).

Specimens were obtained of a conifer that can not be distinguished from the widely diffused Lower Cretaceous plant Sphenolepidium Kur-rianim. They occur on the horizon 100 feet below the Dakota sandstone, at the clifi on the north side of Pine (Jlreek, rather commonly,nbsp;and sometimes in well preserved branching specimens. On the samenbsp;horizon, at the cliff on the south side of Pine Creek, and the cliff ofnbsp;Oak Creek, at Bobbin�s ranch, tire fossils are rarer and not so wellnbsp;preserved.. The best specimens are found on the horizon 60 feet belownbsp;the Dakota, at the cliff in the east bank of Oak Creek. Here somenbsp;very fine, freely branching specimens were obtained. The scale-likenbsp;leaves of this plant in the Hay Creek beds are a little broader thannbsp;those found in the Potomac, jirobably indicating a more luxuriantnbsp;growth, which feature is seen iu a number of the other Hay Creeknbsp;plants.

The specimen represented by Pig. 12 of PI. CLXVI is from the cliff on the north side of Pine Creek, and that by Pig. 13 from the shales onnbsp;the south side of Pine Creek.

1889. Splienolepidiumparcerainosmn Pout.: Potomac Flora, Mon. U. S. GeoL Survey, VoL XV, p. 257, pL cxxix, iigs. 7, 7a, 71); pi. cxxx, figs. 8, 8a; pi. cxxxi,nbsp;fig. 2.

This plant, also first found in the Lower Potomac of Virginia, occurs in the Hay Creek beds. It is confined, like Sphenolepidiuni Kurrianum,nbsp;to the upper member, Jenney�s Ho. 2 of the Hay Creek Lower Cretaceous, and occurs mostly witli that plant and Sequoia Beichenhachi.

It is found on the horizon GO feet below the Dakota sandstone, at the cliff� in the east bank of Oak Creek (PL CLXIII, Fig. 11b), rather commonly, and sometimes in fine specimens. On the horizon 100 feet belownbsp;the Dakota, it is found at two localities: Cliff on the north side of Pinenbsp;Creek, from which were obtained the sxiecimens figured on PI. CLXVIII,nbsp;Figs. 1-3, and cliff on the south side of Pine Creek, being rather common at the first-named locality on Pine Creek.

This plant was described by the writer in Mon. U. S. Geol. Survey, Xol. XV, jip. 257-258. It is well characterized by its long, sparinglynbsp;branched, slender twigs, thickly clotlied with leaves, of which the laterally attached ones have an ovate or elongate elliptical shape and rathernbsp;long acute tijis. They also have a midnerve. The leaves of this plantnbsp;are in shape much like those that Heer has depicted for Sequoia qracilis,nbsp;but are generally more slender. Were it not for the midnerve I wouldnbsp;conclude that it is that Sequoia, showing only a varietal difference.nbsp;Heer, however, states that Sequoia qracilis has no midnerve in its leaves.nbsp;I would be all the more inclined to identify it with this Sequoia, becausenbsp;small, round Sequoia cones, exactly like those of S. qracilis, occur withnbsp;it. This i)lant is highly characteristic of the upper portion of the Lowernbsp;Potomac strata, such as is found near Brooke Station, Virginia, whichnbsp;group is called by Mr. Ward the Aquia Creek series. It forms anothernbsp;of the plants that indicate a similar geological age for the Brooke stratanbsp;and Jenney�s division Ho. 2 of the Hay Creek beds.

1889. Taxodiiim (Glyptostrobus) brookense Font.: Potomac Flora, Mon. U. S. Geol. Survey, VoL XV, p. 254, pi. cxxii, figs. 1, la, lb; pL cxxiv, figs. 3, 3a, 4, 4a, 5,6, 7,nbsp;7a, 8, 9; pi. cxxxi, figs. 5,5a; pi. clxv, figs. 1-3; pi. clxvi, figs. 4,4a, 7; pi. clxvii,nbsp;fig. .3.

1895. Glyptostrobus Srool'cMsis (Font.) Ward: Fifteenth Annual Report U. S. Geol. Survey, pp. 359, 377, 380.

Several good specimens of this plant, first described by the writer from the Lower Potomac of Virginia in Mon. �. S. Geol. Survey, Vol.nbsp;XV, p. 254, occur on the horizon CO feet below the Dakota sandstone,

at the cliff in the east bank of Oak Creek (from which the specimen here figured on PI. OLXWIII, Fig. 4, was obtained), along with Ath-rotaxopsis tenuicaulis and Sphenolepidium parceramosum. It occursnbsp;also, but rarely, on the horizon 100 feet, below tlie Dakota sandstonenbsp;at the cliff on the north side of Pine Greek, as seen in faint impressions on the large slab, PI. CLXW, Pig. 4. In the Lower Potomac ofnbsp;Virginia this form is highly characteristic of the upper or Brookenbsp;group. Like many of the Hay Greek fossils, the twigs of this conifernbsp;are a little stouter than those of the same species found in the Lowernbsp;Potomac. The leaves also diverge rather more from the stem than donbsp;most of those from the Potomac. This, however, is probably due tonbsp;differences in the inodes of preservation.

p. 19o, pi. l.vxv, tigs. 1, la, lb; pi. Ixxvi, fig.s. 2-6; pi. Ixxvii, figs 1 2��i� Ixxviii, figs. 1-0; pi. Ixxix, fig. 7; pi. Ixxxv, figs. 1, 2, 8, 9.nbsp;nbsp;nbsp;nbsp;^nbsp;nbsp;nbsp;nbsp;'

111 the Hay Creek series detached fragments of leaves occur thnt are so much like Aageiopm longifoUa that they may, with little hesitf

Potomac of Virginia, in some fine specimens. It was described hv tiJ writer ill Mon H. S. Geol. Survey, Vol. XV, p. 195. The distinctivenbsp;characters of ^ageiopsis as compared with Podozamites are found Innbsp;the basal and terminal portions of their leaves; that is, the charactersnbsp;that may be seen in the detached leaf. As tlm Hay c�reek speS�eunbsp;nowhere show these portions of the leaves, we can not be certain thatnbsp;these fragments are Xageiopsis; but the texture, shape, size, and othernbsp;features of the fragments, as well as the nervation, agree so well w nnbsp;N. longifoUa that the identification is.jnstified.

Sir William Dawson, in his paper on the � Mesozoic floras of the PocLt. Mountain region of Canada� (Trans. Eoy. Soc. Can., Sec. IV Vol IhI nnbsp;6, pi. i, fig. 3, describes a plant from the Kootanie series nf it ^�1nbsp;which he identifies with Foclozamites lanceolatus. This is in ^0^1nbsp;re.spects much like Nageiopm longifoUa, being the termination of Inbsp;lea,. Bis Lardly possible tbaUbls Podosa.olfes has � �l � ./enbsp;the Norlhen, Hem.spbere^o its geograpbleal distributioo. aed from thenbsp;Triassic into the Lower Cretaceous in its o-Anm,vm,.inbsp;nbsp;nbsp;nbsp;o ,nbsp;nbsp;nbsp;nbsp;. ,

Zamites Gopperti, also from the Urgonian of tL Weriisdorfbei� seems to benbsp;nbsp;nbsp;nbsp;UnpifoUa. The form he gives i^ itls pCe,

der Wernsdorler Schichten (Palaeontographica, Vol. XIX), pi. iii T 6 IS just what would be seen in W. longifoUa if the lower surface of a

large leaf be presented uppermost, so that the stem partially hides the insertions of the leaflets.

N'. longifolia occurs, so far as yet seen, only at the horizon 150 feet above the Jurassic, at the clilf on the north side of the valley of thenbsp;South Fork of Hay Creek, and also at shales under the third sandstone,nbsp;Barrett. It is quite common at the former locality and rather rare atnbsp;the latter.

Both the specimens figured are from the bed of shales under the third sandstone, 50 to 100 feet above the coal at Barrett.

1889. Nagetopsis angustifolia Font.: Potomac Flora, Mon. U. S. Geol. Survey, VoL XV, p. 202, pi. Ixxxvi, figs. 8, 9; pi. Ixxxvii, figs. 2, 2a, 3, 4, 5, 5a, 6, 6a; pi.nbsp;Ixxxviii, figs. 1, 3, 4, 6-8; pi. Ixxxix, figs. 2, 2a.

A single leaflet of a plant that appears to be identical with Nagei-opsis angustifolia occurs on the horizon 150 feet above the Jurassic, at the shales under the third sandstone, Barrett. This species wasnbsp;described by the writer in Mon. IJ. S. Geol. Survey, Vol. XV, p. 202.nbsp;It is one of the most widely diffused species of the Virginia Potomacnbsp;formation. Although the leaflet is well characterized, and can hardlynbsp;be anything but this Xageiopsis, I do not make the identification positive, as the amount of material is so small.

1889. liaieropsis adiantifoUa Font.: Potomac Flora, Mon. U. S. Geol. ,Survey, Vol.

XV, p. 211, pi. xcii, figs. 8, 8a, 9; pi. xoiii, figs. 1, la, 2, 3; pi. xciv, figs. 2, 3.

Fragments of detached leaves of a plant which seems to be identical with Baieropsis adiantifoUa occur not very abundantly in the Haynbsp;Creek beds, and only at the horizon 150 feet above the Jurassic. Thisnbsp;plant was found by the writer in the Lower Potomac of Virginia, andnbsp;was described in Mon. U, S. Geol. Survey, Vol. XV, p. 211. The Potomac specimens yield some forms that are much more complete thannbsp;any found in the Hay Creek beds. Still, as the leaves are of peculiarnbsp;shape and have a lobing not found in any others, and as these pointsnbsp;are clearly indicated in the specimens drawn, there does not seem to benbsp;much room for doubt that the Hay Creek forms are really B. adiantifoUa. Most of the Hay Creek specimens do not show the margins ofnbsp;the leaves, or, indeed, their shape. On one of these, however, the characteristic nervation of B. adiantifoUa was visible. This nervation isnbsp;marked by fine but sharply defined and closely placed nerves that fork

so as to spread iu a fan-shaped manner. In the specimen figured we have a more complete fragment of a leaf. It shows enough to indicatenbsp;that the shape of the leaf was the characteristic one of the speciesnbsp;now in question and it has in addition preserved, in the right-handnbsp;lower corner of the leaf two of the characteristic lobes and teeth ofnbsp;B. adimiUtoha. Ihe teeth are not preserved well enough to show thenbsp;spike-hke tips in which they terminate. These, however, are hardlynbsp;ever visible, even m the best preserved Potomac specimens.

In the Hay Creek beds this plant occurs in a considerable number of tragments, a the cliff on the north side of the valley of the South Fork

Hay Cre^ek and m one specimen (that here figured) at the shales under the third sandstone, Harrett.

Two speoime,.* of o �l�t tb�t is .��d, like Bmerop.i. �luHp�rUta were found on tbe borieon 100 feet below tbe Dakota sandstone at thenbsp;elifton the north side of Pino Creek. B. plurifarUU was found�by tienbsp;writer in the Lower Potomac of Viro-inin ��r; �nbsp;nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;a ^ue

described in Mon. �. S. Geoi. Survey,Vol. XV, p. 208.�'wi'iT� tae IW Creek specnens are ouite fragmentary, they show euonsh to stron-hnbsp;mdicate their identity with the Potomae species. We may rely mSienbsp;fully on conclusions drawn from a small amount of materinUu tlfe ci�nbsp;of such leaves as this than where leaves are concerned that belong- tonbsp;a type common to many different plants. Still, as we have only fwonbsp;imperfect specimens, I make the identification doubtful.

A fossil not to be distinguished from HeerV first found in the Wealden of PortiigaL ol.u-s in ttTquot;nbsp;of the Hay Greek series, Lower Cretaceous It i ^ rnbsp;nbsp;nbsp;nbsp;Piembers

iirz:rrT,rhTriirTh^^^^^^^^

and 1 think it, as well as Heer�s plant, is a true Baiera. Heer describes bis forms in Contr. a. la Flore Foss, du Portugal, p. 18. The descriii-tion that Heer gives applies to the Hay Creek plant, viz, the leaves arenbsp;divided into lacini� in a dichotomous manner. The lacinim are fromnbsp;1 to 2 mm. wide and have several nerves. The �gures of Heer represent that the leaf had at base a single narrow lacinia, and this, bynbsp;repeated dichotomous subdivision, gave origin to the leaf. The basalnbsp;lamina, as in the Hay Creek plants, probably passed downward intonbsp;a petiole. Heer�s figures represent the lacinise more crowded togethernbsp;and looking as if the leaf had been stretched by pressure in the direction of its length. In the Hay Creek specimens the pressure seems tonbsp;havm operated to spread out the lobes. Heer�s fig. 11 of iil. xvii represents the specimen of his plant that is nearest to our forms. He saysnbsp;of the nerves of his plant that they are distinct, but in the Hay Creeknbsp;specimens they are seen with difficulty. Probably this distinction isnbsp;caused by differences in the mode of preservation. The ultimate laciniicnbsp;of the Hay Creek plants are only 1 mm. in width, and it is possible thatnbsp;the subdivision was carried further than was seen.

The shale of the two localities furnishing this plant, although given by Professor Jenney as separated by 100 feet of strata and as occurringnbsp;at different places, is strikingly alike, being very flue grained andnbsp;fissile, the substance of the plant iieeliiig off from the stone like paper.nbsp;It preserves the plants well, and additional collections should be madenbsp;from it.

1889. Cephalotaxopsis magnifoUa Font.; Potomac Flor.a, Mon. U. S. Geol. Survey, Vol. XV, p. 236, pi. civ, tig.s. 4, 5; pi. cv', figs. 1, la, lb, 2, 4; pi. cvi, figs. 1,nbsp;la, 3; pi. cvii, figs. 1, 2, 4, 4a; pi. cviii, figs. 1, 3, 1.

Leaves that are identical with those of Geplialotaxopsis magnifoUa, as described in Mon. U. S. Geol. Surv., Vol. XY, p. 236, from the Loivernbsp;Potomac of Virginia, are found sparingly on the horizon 150 feet abovenbsp;the Jurassic, at the cliff on the north side of the Valley of the Southnbsp;Fork of Hay Creek, and in shales under the third sandstone, Barrett.nbsp;They are found also on the horizon 100 feet under the Dakota, at thenbsp;cliff on the north side of Pine Creek. At these localities they are bynbsp;no means common. With the larger leaves, corresponding to those ofnbsp;C. magnifoUa, are others that agree better with those of G. ramosa. As,nbsp;however, none of the leaves are attached to stems, the data are not sufficient to justify their seiiaration into two distinct species. The probabilities, however, are that two species are present. The leaves ofnbsp;Cephalota.xopsis seem to have been drifted some distance. As the nutlike fruit GarpoUtJms montmm-nigrornm occurs at the same locality

with these leaves, and as this is much like C. fmciculatm, which is found in the Potomac strata with many fine specimens of Cephalotax-opsis and as also Oephalotaxus has similar fruit, it is probable thatnbsp;this Carpolithus is the fruit of some Oephalotaxopsisnbsp;The specimens represented on PI. CLXII Pig lb -ud PI CLXIXnbsp;Pig. 4, are from the north side of the valley of the South Porii of Haynbsp;Creek, miles west of Barrett. The other specimen (PI CLXIXnbsp;Pig. 3) is from the shales under the third sandstone above the coal atnbsp;Barrett.

A nbsp;nbsp;nbsp;�meut � tom,a �� a,,nbsp;nbsp;nbsp;nbsp;150nbsp;nbsp;nbsp;nbsp;J

at the d,� �� the aorth sale of the valley of the Soath Fork of Ha^ Creek, which is probably the male aa.ent of eoi.fe conifer. It Is onitenbsp;we 1 preserved .ami shows a length of 1 cm., with a width of 4 I,,,.,nbsp;.noli,ding the deflected bracts. The form is cyliadricai, with both emlinbsp;obtuse The bracts on the upper face are mostly removed, being takennbsp;oil in the splitting ot the shale along the plane of the ament. Hence

mi 1 h 1 1 nbsp;nbsp;nbsp;4-nbsp;nbsp;nbsp;nbsp;iougtu. It IS comparatively stout

In the Lower Cretaceous series of the Hay Creek region dicotyledons occur only in the highest portion in Professor Jenney�s division No lt;gt;nbsp;In the strict confinement of this type of vegetation to the upper portionnbsp;the Hay Creek Lower Cretaceous differs from the. Lower Potomac asnbsp;shown in .Pirgmia Ihis latter formation shows iu its older portion anbsp;few dicotyledons of peculiar archaic type, unlike anything found in the

ever, a maPked resemblance between the Hay Creek dicotyledons and those of the upper Brooke beds of the Virginia Potomam In bothnbsp;cases the type of dicotyledons is more modern in ffm.Aki finbsp;nlement fmn.d In .be �ide. bed. of .be Lowe. C � �*'7.nbsp;m .�.poemble to �y whether or not there ie really a ditfere.me in thenbsp;occurrence ot diootyledone m these two widely separated ter.auee ofnbsp;Lower tiretaceous. The collections made thus far in the Hay Creeknbsp;region are very scanty, and it may be true that more persistent searchnbsp;Mill disclose dicotyledons of ancient type in the lower Hay Creek bedsnbsp;It is from these beds that the collections are most scanty. Conclusionsnbsp;based on the fai are to hnd certain forms, are at best uncertain, andnbsp;they are especmlly so when the collections can not be taken as fairlynbsp;represeutiiig the tiora.nbsp;nbsp;nbsp;nbsp;^

Ill the case of the Hay Creek Lower Cretaceous flora we may fairly conclude that dicotyledons were relatively not very abundant on anynbsp;horizon, and, granting that they existed iu the time of the dejiositionnbsp;of the lower beds, they formed ]iroportionally a much smaller elementnbsp;of the vegetation than during the era of the formation of the upjiernbsp;strata. The collections show that even in division �To. 2 the ferns andnbsp;conifers far surpassed the dicotyledons. The case is very differentnbsp;when we pass above No. 2 into the true Dakota formation. Here conifers, cy cads, and ferns become insignificant in numbers, and dicotyledons attain an overwhelming predominance. The facts that arenbsp;indicated by the Hay Creek dicotyledons, so far as the evidence nownbsp;attained goes to show, are similar to those made out from the study ofnbsp;the Lower Potomac beds. Dicotyledons of modern asjiect apiiear innbsp;some force in the upper strata of the Hay Creek Lower Cretaceous, butnbsp;they do not form the dominant element in the flora.

A fragment of a small dicotyledonous leaf was found on the horizon 100 feet below the Dakota sandstone, at the cliff on the north side ofnbsp;Pine Creek. The fragment shows intact the left side of the base, anbsp;lobe, and the sinus between this and the next higher lobe, which isnbsp;only partially preserved. The indications are that this latter is similarnbsp;in character to the lowest lobe, which is fully preserved. The basalnbsp;portion of the leaf is rounded off and iiasses into the lowest lobe withnbsp;a considerable convexity in the margin of the leaf. The lobe that isnbsp;preserved is oblong, with an elliptical-shaped tip that is turned slightlynbsp;outward away from the midrib. One of the primary veins of the leafnbsp;passes into this lobe to its tips. The sinus between this and the nextnbsp;lobe forms a narrow, acute, inverted triangle. A similar primary nervenbsp;passes into the second partially preserved lobe. The upper portion ofnbsp;this latter lobe and of the leaf, as well as nearly all of the right-handnbsp;half of the leaf, are wanting. Not enough of the leaf is preserved tonbsp;fix its true position. It may belong to any one of several genera. As,nbsp;however, it seems to be nearer some of the forms of Quercus than to anynbsp;other genus, I place it provisionally in the allied genus Quercophyllum.nbsp;It should be noted that it has the facies of a recent type of leaf. Itsnbsp;importance as a fossil lies in the fact that it is distinctly a dycotyledonnbsp;that is different from the others found in the Hay Creek Lower Cretaceous, and that the archaic features are not shown in it.

A tagmenl of a small loaf ,nito di�ore�t from the other Hay Crook dicotyledons was found on the hormon 100 feet below the Dakota sandstone, m the Carbonaceous shales M Eollin�s tunnel. It is 2 cm lonenbsp;and II mm wide, with hut little variation in the width from end to enrfnbsp;The entire leaf was probably oblong i� jbape, or lanceolate. The leafnbsp;tetare seems to have been liriu and durable, and the nerves are butnbsp;faintly shown. The midrib is slender. The secondary or lateral veinsnbsp;go off from the midrib ah,lost at right angles. They are parallel, placednbsp;at eijua distances and slightly arched in the middle, with the r endsnbsp;directed toward the einl of the leaf. They are all of equal strength

and are placed about 1.5 mm. apart. No nervation other than the ndd-rib and lateral veins was seen.

The general aspect of this leaf is much like that of a fern of the Angioptoridium type, and It resembles some of the pinnules of Anoio.nbsp;ten*.� ��me, as, for eiample, that given in Mon. U. S Geolnbsp;Survey, Fd. XV, pi. siiv, Jg. g; bnt this leaf has a iniioh alendere)nbsp;midrib, and the lateral nerves do not fork. Besides, these nerves havlnbsp;the appearance of the nerves of a dicotyledon rathe; than of a fernnbsp;Not enongh of the plant has been found to determine positivdy itsnbsp;time position. It may belong to anyone of several generaof Lotyledomnbsp;The nerves are closer ban is usual in dicotyledons of this type I, J

perhaps nearest to IJlinns, and I place it provisionally in tL allied genus Ulmipbyiluin.

1889. Ficophyllum serraium Font.: Potomac Flora Mod tt s n i r, p. 294, pi. oxlv, fig. 2; pi. cxlix, fig. 9.nbsp;nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;�

Ficophyllum serratum^^, found in the Lower Potomac of Virginia and described by the writer in Mon. F. S. Geol. Survey Vol XVnbsp;pi. cxlv fig. 2; pi. cxlix fig. 9. A fragment of a dic�otyledonons leafnbsp;was Ob ained in division Xo.2 of the Hay Creek beds that so stronglynbsp;resembles this that it may safely be identified with it The fossil nownbsp;in question occurs on the horizon 00 feet below the Dakota sandstonenbsp;at the cliff in the east bank of Oak Creek. Only one specimen wasnbsp;19 GEOL, PT 2-44

found. It sliows a portion of the lower part of the midrib and a large part of the right-hand half of the leaf. The fossil indicates a leaf of thenbsp;same size and character as that shown on pi. cxlis in fig. 9 of Mon.nbsp;U. S. Geol. Survey, Vol. XV. The tendency� to form double teethnbsp;seen in the leaf depicted in fig. 9 does not appear here. That, however, is not a persistent feature in the Potomac plant.

1889. Sapindopsis variahilis Pont.: Potomac Flora, Mon. U. S. Geol. Survey, Vol. XV, p. 298, pi. cli, figs. 1, la; pi. clii, figs. 1, 4, 4a; pi. cliii, fig. 3; pi. cliv,nbsp;figs. 2-4, 4a; pi. civ, figs. 2-5.

Sapindopsis variahilis was first found by the writer in numerous well-preserved specimens in the upper or Brooke group of beds belonging to the Lower Potomac. It is described in Mon. U. S. Geol. Survey,nbsp;Vol. XV, pp. 298-300. It is highly characteristic of the upper portionnbsp;of the Lower Potomac in Virginia, and great numbers of its fossils arenbsp;found at some localities. It is by far the most common dicotyledon atnbsp;the localities where it occurs.

Precisely similar leaves occur in division No. 2 of the Hay Greek beds. They are found on the horizon GO feet below the Dakota sandstone, at the cliff in the east bank of Oak Greek, where it is the mostnbsp;abundant dicotyledon, and is quite common, and where the specimennbsp;here figured was obtained. It is, in fact, the only abundant dicotyledonnbsp;in the Hay Greek Lower Gretaceous. It occurs also on the horizon 100nbsp;feet below the Dakota sandstone at the cliff on Oak Greek, at Bobbin�snbsp;ranch. Here it is found sparingly, but in well-preserved forms. Thisnbsp;plant is a valuable one for the determination of the age of the beds innbsp;which it occurs, for it has a number of features that render it easy tonbsp;identify, and which cause it obviously to differ from others. Thenbsp;leaves have a thick, very durable texture, that causes them to be muchnbsp;better preserved than most dicotyledons. The odd-pinnate leaves,nbsp;owing to the persistence of the leaflets at their summits, frequentlynbsp;show them attached, and sometimes even the terminal leaflets. Thenbsp;nervation is strongly marked and characteristic. Indeed, these leavesnbsp;can hardly be mistaken for others. It is signiflcant to find that thisnbsp;plant, which is the most abundant in the Brooke group of the Virginianbsp;Lower Potomac, is the most common dicotyledon in the upper membernbsp;of the Hay Greek Lower Gretaceous. As indicating similarity of age,nbsp;such a plant is much more important than any single species, which isnbsp;vaguely characteristic and represented by few individuals. This Sapindopsis is �at home� and well established in the upper portion of thenbsp;Lower Gretaceous of both the Hay Greek region and of Virginia.

from the compactly bnilt chafty .a.nente aeerlbed to omifere. �'1�*� length of about 1 cm. and a width of ohnnf qnbsp;nbsp;nbsp;nbsp;mi . .

IiVCEETr� SEDIS.

F'RUITS.

The following fruits have not heAn Tma.a/i nbsp;nbsp;nbsp;. ,nbsp;nbsp;nbsp;nbsp;. ,

in a way to indicate where they belong in nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;foliage

�� TC�quot;s;�h�;.'r^quot;�'' nbsp;nbsp;nbsp;=��. ti.�,. v�.. XV,

On the horizon lo� feet above the Jurassic, at the cliff on the north side of the va ley of the South Port of Hay Creek, a single linpri �nbsp;as from a nut-like fruit, was obtained. This in �LcL .. inbsp;tical with one of the fruits of GarpoUtlms fasciculJus fromquot;

U. S. Geol. Survey, Vol. XV, p. 265, pl- cxxxiv fig ^ culatus, as found in the Potomac of Virginia shnw= ^ Mnusfasct-frnits bom. on a common stem. The fS�l� 7! �nbsp;nbsp;nbsp;nbsp;'�'�-�t�

plnm-like fruit, two or three in a head and as r� ^ otaxns has a folia occurs at this locality, this fruit may belong to ThflTtT*** T^�-'

The genus Xageiopsis, which is abundant in iLa t -r. l Virginia, and highly characteristic of it, was establisheTby the wXnbsp;for certain leaves and leafy branches that agreed closelv wbll ti?!nbsp;living genus Hageia Gaertner, generally regarded as a sabgenns of

Podocarpus Endlioher, now surviving in the Bast Indies and Japan. When the description of tlie genus was written I had not seen eithernbsp;the foliage or fruit of Nageia. Since that time, however, through thenbsp;kiudnegs of a friend in Japan, specimens of both have been obtained.nbsp;My conclusion as to the close resemblance of the foliage of �fageia andnbsp;and �lageiopsis has been strongly confirmed by an inspection of these.nbsp;The fruits of the living Uageia are so much like some of those of thenbsp;Lower Potomac of Virginia, which I described as belonging to thenbsp;groups Oarpolithus and Cycadeospermum, especially the latter, that Inbsp;think it quite probable that some of the Oarpolithus forms and perhapsnbsp;all of Cycadeospermum are fruits of Nageiopsis. It is true that mostnbsp;of the Nageias have single nut-like fruits, but Nageia Blumei Endl.nbsp;[Podocarpus Blumei Endl.) is described as having its fruit, after the fallnbsp;of the floral leaves, grouped in bunches at the ends of the braiichlets.nbsp;Hence it may be that even branched nutlets, like those of Garpolithusnbsp;fasoiculatus may belong to �lageiopsis.

Pig. 11 of PI. OLXIX shows this nut natural size, and Fig. 12 is eidarged 2 diameters.

A nut-like fruit, which is probably a new species of Oarpolithus, was obtained on the horizon 150 feet above the Jurassic, at the cliff on thenbsp;north side of the valley of the South Fork of Hay Creek. It is ovatenbsp;in shape, 15 mm. long, and, including the rind or margin, 10 mm. widenbsp;at the widest part, which is close to its base. It has a distinct winglike margin, which is flat, while the body of the seed is strongly convex, indicating that the margin was thinner than the seed jiroper. Innbsp;shape and size it resembles Gycadeospermuni spatulatum Font., of thenbsp;Lower Potomac of Virginia. This latter was figured in Mon. IT. 8. Geol.nbsp;Survey, Vol. XV, pi. cxxxv, figs. 11,21. The Potomac fruit, however, hasnbsp;no wing, and is a thinner seed with a less firm texture. This seed maynbsp;be the fruit of Oephalotaxopsis magnifolia Font., for this plant occurs atnbsp;this locality, and the fruit of Ceijhalotaxus is fleshy, with a hard woodynbsp;seed within.

The fossil here named Garpolithus harrensis was obtained on the horizon 150 feet above the Jurassic, at .lolin Barr�s tunnel. It has annbsp;ovate shape and is 9 mm. long, with a maximum width at its lowernbsp;portion of about 4 mm. As it leaves a pretty deep imprint in the shale,

1 Professor !Fontaine in his manuscript designates this form hy a name that had been twice used before and therefore it was necessary to change it.

2The name that Professor Fontaine gave this form in his manuscript has already been given to three different objects by different authors. As it was found at Barr�s tunnel it may be callednbsp;G. harrensia.

it was probably quite tliick and firm iu texture. It is a good deal like Garpolithiis virginiensis Font., but it is more elliptic in form than thatnbsp;and proportionally narrower, and had apparently a less woody texture.nbsp;It may prove identical with the seed of Araucarites toyomingensis, butnbsp;the differences seem to justify its doubtful separation as a new snecies.

1889. CaiyoUthus virginiensis Pont.: Potomac Flora, Mon. U. S. Geol. Survey, Vol.

XV, p. 266, pi. cxxxiv, figs. 11, 11a, 12, 13, 14, 14a; pi. cxxxv, figs. 1, 5; pi. clxviii, figs. 7, 7a.

Several detached nut-like seeds were found on the horizon 100 feet below the Dakota sandstone, at the cliff on the north side of Pinenbsp;Creek. They are not attached to a stem, as were some of the forms ofnbsp;Oarpolithus virginiensis, which were found iu some abundance in thenbsp;Lower Potomac of Virginia, and described in Mon. U. S. Geol. Survey,nbsp;Vol. XV, p. 26G, but they resemble strikingly the detached seed of thisnbsp;Xdant. The resemblance is strong enough to justify the identificationnbsp;of the Hay Creek seed with those of the Potomac. Like the Potomacnbsp;seeds, those of Hay Creek seem to have had a firm woody texture.nbsp;One of the seeds has a short pedicel, indicating that it was attachednbsp;to a stem after the manner of the Potomac specimens.

This is a narrowly elliptical or fusiform seed, occurring in the strata at the junction of the Jurassic with the Cretaceous at Lon Cottle�snbsp;ranch. It is 5 mm. long, with a maximum width of 1.5 mm. It hasnbsp;attached to it what looks like a portion of a wing. Possibly this is annbsp;abnormal seed of Araucarites wyomingensis, but more probably it isnbsp;the seed of a different species of Araucarites, as it is proportionally toonbsp;narrow for A. icyomingensis.

Pig. 17 of PI. CLXIX represents it natural size, and Pig. 18 enlarged 2 diameters.

Genus PEISTMAXTELIA Ward n. gen.

FusifoT'iii OT ci()(iT-sliG,ped l�icivhiugs,�Oertaiii peculiar oblong and fusiform markings are found not rarely on the horizon 100 feet belownbsp;the Dakota sandstone, at the clift on the north side of Dine Greek,

* The name given to this form hy Professor Fontaine in his manuscript was preoccupied. The one I have chosen is derived from the Latin word for bay, iu vague allusion to the Hay Creek coal field.

They appear on the surface of the rock as convex forms that are casts of concave shapes that existed apparently on woody stems of considerable size in the cambium layer under the bark. They are not arrangednbsp;in a strictly definite manner or with unvarying pattern. They havenbsp;their longer dimensions in the direction of the length of the stem onnbsp;which they occur, and are arranged mostly in interrupted rows, withnbsp;the individual markings more or less en �chelon, with their ends sometimes overlapping. Sometimes they are close together and touch fornbsp;most of their length. Some are curved, but most of them are straight.nbsp;These markings have a sufficiently constant and definite character tonbsp;enable one to recognize them at a glance. They occur only at certainnbsp;horizons. Hence we must infer that they are not the results of merenbsp;accident. Another fact that gives them significance is their occurrencenbsp;in the same way and with the same shapes in the Lower Potomac ofnbsp;Yirginia. In this they are found on the same horizon at Fredericksburg and at Cockpit Point. I can offer no satisfactory explanation ofnbsp;them, but they are worthy of description, for they clearly belong tonbsp;the wood of a particular kind of tree occurring only in the Lowernbsp;Cretaceous on a definite horizon.

Note.�The above was Professor Fontaine�s description of these objects, and Fig. 19 of PI. CLXIX is a fairly good illustration of their appearance. I was withnbsp;him when the specimens of this plant referred to by him from Cockpit Point, on thenbsp;Potomac River, in Virginia, were found on the occasion of our visit to that localitynbsp;on .July 27, 1893, and the specimens we then collected now lie before me, as do alsonbsp;those from the Hay Creek coal field. Professor Fontaine states that others werenbsp;obtained from Fredericksburg, hut these I have not seen. The Fredericksburgnbsp;horizon is the same as that of Cockpit Point, viz., his Fredericksburg or my Rappahannock series of the Potomac formation.

In addition to these three localities, I last summer found the same plant in the Cheyenne sandstone of Kansas. It is qnlto abundant in what Professor Cragin hasnbsp;called the Lamphier shales, and also occurs in the more carbonaceous portions ofnbsp;his Stokes sandstone. Referring to my notes, I find first the mention of broad stemsnbsp;resembling bamboo and subsequently of these peculiar �cigar-shaped markings identical with those from the Black Hills and Cockpit Point,� so associated with thenbsp;broadbamboodike stems �that it was easy to ho sure that they belong to the stemsnbsp;and occur in the interior as a part of the internal structure.� These specimens arenbsp;now in temporary storage and I can not confront them with the others, but I wasnbsp;too familiar with them to have been mistaken, as the Cockpit Point specimens hadnbsp;greatly interested me and led me to make a prolonged search for similar objects previously figured by other authors. I will now give the result of that investigationnbsp;supplemented by some later discoveries.

Of all the figures thus far found that which Feistmantel gives in his Flora of Kach (Foss. FI. Gondw. Syst., Vol. 11, Pt. I, 1876, pi. x, fig. 2) comes the nearest to thenbsp;American forms. In fact, it is substantially identical and must represent the samenbsp;genus. It is for this reason that I dedicate this new genus to the late Dr. �ttokarnbsp;Feistmantel, for whom, notwithstanding his numerous and important contributionsnbsp;to paleohot.any, no genus of fossil plants has been named, and very few species.

�Portion of a stem of a coniferous plant.�The specimen which I have figured here seems to me to he undoubtedly a fragment of the stem of a coniferous plant. Thenbsp;scars, it is true, remind one very much of a lycopodiaceous plant, hut no Lycopo-

(liace� have quot;been found anywhere in Mesozoic strata. The scars are spirally disposed, oblong, with the broader portion above, where, I believe, leaves were inserted. The lower portion is narrower and elongate, hut no other structure is to be seen. Ifnbsp;we compare these specimens, however, with stems of living coniferous plants, wenbsp;shall find that the structure of the young branches is similar. Rut to describe andnbsp;determine them more exactly is, I believe, not possible, because it is always verynbsp;difBcult to recognize a plant only from a fragment of the stem. We can only saynbsp;that the stems belong, perhaps, to one of the coniferous plants found in the samenbsp;locality, and two especially may be suggested, the Pachyphyllum, or the plant tonbsp;which the scales I shall next describe belonged. I believe this stem can not benbsp;referred to Echinostrobus Schimp,, as the leaves are quite different.� In thenbsp;description of the plate of fig, 2 he simply says: ^^Stem of a coniferous plant, withnbsp;leaf sears. �Prom Kukurhit. �

Next to this in point of similarity to our forms I place three figures of Stokes and Webb in their report on Mantell�s collection from the Tilgate Forest in Sussexnbsp;(Wealden), contributed to the Geological Society of Loudon and published in itsnbsp;Transactions in 1824 (Trans. Geol. Soc. London, 2d Ser., Vol. 1,pp. 421-424, pi. xlv-xlvii). These are the figs. 8 of pi. xlvi and figs. 4b and 4c of pi. xlvii, all of whichnbsp;are regarded as parts of their Clathraria anomala, and the first of them is still includednbsp;by Seward (Wealden Flora, Pt. II, p. 123) in Bucklandia anomala, which is the modernnbsp;name of that same jjlaiit. It is generally admitted that these are the piths of cycad-ean trunks, and for this class of objects Saporta proposed the name Cycadeomj'elounbsp;(Plantes Jurassiques, Vol. II, p. 331).

Saporta did not, however, deal with the English Wealden forms, and only included under his new genus so much of the plant described by Schimper (Trait� de Pal.nbsp;V�g., Vol. II, P- i-83) under the designation Clathraria liasina as related to certainnbsp;pith casts found at Hettanges near Metz. Schimper thought that these objects represented the woody cylinder of cycadeau trunks (he does not say the medulla), andnbsp;ho suggested that they might lieloug to Olozamites major. He did not figure any ofnbsp;the specimens, and the only figure I have seen of this plant, which SajTorta callednbsp;Ciicadeomyelonhetiangense, is that of the Plantes Jurassiques, Vol. II, Atlas, pi. cxix,nbsp;fig. 5. This also presents a remarkable similarity to the American Lower Cretaceousnbsp;forms under consideration, and I was at first tempted to refer these to Cycadeomyelonnbsp;and class them with the Cycadales; but certain weighty considerations deter menbsp;from this course.

The only other figures that I have thought it worth while to compare are those of Germar�s Oniphalomela scabra (Palaeontograpbica, Vol. I, pi. ill), which are withoutnbsp;much doubt pith casts of cycads, and were referred by Schimper to Clathraria andnbsp;called Clathraria f Germari (Trait�, Vol. HI, p. 5.54). The markings here are quitenbsp;different from those heretofore considered and approach more closely to those seennbsp;on the medulla of other cyeadean trunks of which we have knowledge, some of whichnbsp;are described in this paper (of. Cycadeoidea StillwelU, supra, pp. 636, 637, PI. CXLIX)nbsp;and others elsewhere (see Proc. Biol. Soc. Washington, Vol. XI, p. 13).�

The principal ohjeotion to regarding the American forms as distinct from Cyoa-deomyelon and for seriously doubting that they really represent the medulla of cyeadean trunks is that the markings appear in all cases to he on the inner wall ofnbsp;the hollow cylinder of some vegetable trunk, and not on the outer surface of thenbsp;medullary axis, i. e., in precisely the reverse position from those of Cycadeomyelon.nbsp;lu the case of the Indian plant, although leistmantel supposed that the markiugsnbsp;were leaf scars on the snifaco of coniferous stems, there is nothing in his figures tonbsp;negative the idea that they might be internal. He speaks as if he had consFderablenbsp;material, and this question could perhaps be settled by an examination of it. Innbsp;many of our specimens it would he difficult to decide whether the scars occupiednbsp;an outer or an inner surface, and Professor Fontaine, in his description given above,nbsp;does not clearly indicate what his view of the matter is by saying that � they appear

on the surface of the rock as convex forms that are casts of concave shapes that existed apparently on woody stems of considerable size in the cambium layer undernbsp;the bark.� This, it seems to me, might admit of either interpretation. As I nownbsp;examine the specimen figured by him I think I see evidence that the projectionsnbsp;were inward, and other material that he did not figure confirms this impression.nbsp;The specimens from Cockpit Point present the same difflcnlty, but one of these prettynbsp;clearly indicates that it forms the thin edge of a flattened hollow due to pressure,nbsp;and represents itself the investing layer of whatever may have once occupied thisnbsp;hollow space. � Put with this my observations in Kansas, which left no doubt in mynbsp;mind that the bamboo-like stems on parts of which these markings occur were thenbsp;interior parts of large hollow trunks, and the evidence becomes strong that our plantnbsp;is not a Cycadeomyelon or anj^ other �myelon� or pith, but T�art of a hollow moldnbsp;with the elevations directed toward the center of the trunk.

The species of Feistmantelia will depend chiefly on the shape of the elevations. Those of Feistmantel�s figure are decidedly fusiform, with the upper end of thenbsp;spindle much larger. That form may therefore be called Feistmantelia fnsiformis.nbsp;His statement that they are �spirally disposed� is scarcely justified by the figure,nbsp;but here, as in all other cases observed by me, they are alternately disposed, i.e.,nbsp;lying side by side, but each one beginning and ending at a different point from itsnbsp;neighbor, which is a characteristic feature of Cycadeomyelon, and strongly suggestsnbsp;a connection with the medullary rays. The Cockpit Point specimens have some ofnbsp;the half-reliefs somewhat fusiform, but often simply oblong, i. e., half cylindersnbsp;abruptly rounded at the ends. This latter is almost the only form preserved by thenbsp;Hay Creek specimens, and ou this account I have preferred the specific name aWonga.

This plant affords a good example of the geological value of certain kinds of objects which appear to have very little value for biology. Many paleobotauistsnbsp;look with contempt upon anything whose systematic position is in doubt and declarenbsp;that it does more harm than good to list forms which can not be referred withnbsp;practical certainty to some definite family or genus. They argue, correctly enough,nbsp;that the attempt to draw conclusions from such material as to the history of plantsnbsp;is wholly misleading and vitiates all reasoning from fossil plants. They forget, ornbsp;never seem to have thought, that a form may have a geological value quite independent of all such conclusions. Such reasoning is really biological after all, i. e.,nbsp;it is an attempt to work out the genealogy of certain groups of vegetation. Thenbsp;forms, such as this one, are worthless for this purpose and any attempt to employnbsp;them in this manner can not be too strongly condemned. The value they have isnbsp;what is called geognostic. If, as in the present case, the objects are clear and definite,nbsp;so as to be readily recognizable whenever found, and especially if, as also in thisnbsp;case, they are confined to certain geological horizons, they become useful indicesnbsp;and characteristic marks of geological formations, and, wisely employed, becomenbsp;valuable aids to geology. If these peculiar markings had only been seen once, theynbsp;might be regarded as mere lusns naturw and neglected; but when we find themnbsp;under practically the same conditions at about the same horizon and all exactlynbsp;alike in widely different parts of the country', we begin to see that they representnbsp;similar beds and add important testimony to the similarity in age.

All the American forms have occurred in the Lower Cretaceous, and their range, so far as now known, is from near the base of the Cretaceous to near the top of thenbsp;beds that lie below the Dakota group or Cenomanian of Europe, i. e., from thenbsp;Keocomian to the Gault or Alblaii of Old World nomenclature. If the specimensnbsp;from India are the same as ours, this carries the genus down to the Lias, providednbsp;the beds of Kach have been correctly correlated. When the .Inrassic of America isnbsp;better know'n we may expect to find representatives of this plant in them, but therenbsp;is reason to believe that the species will differ in the same way that they do in othernbsp;better-understood genera. It will be further observed that this range is about thenbsp;same as that of the fossio cycads in general, which may or may not be taken as annbsp;argument for the cycadaceous nature of Feistmantelia,�L. P. W.

The preceding descriptions include all the fossil plants obtained thus far from the Lower Cretaceous strata of the Hay Creek region that arenbsp;sufficiently well characterized to be worthy of mention. Incidentallynbsp;in the descriptions of the plants, attention has been called to some ofnbsp;the localities which seem worthy of having additional collections madenbsp;from them. There are some other localities equally worthy of furthernbsp;attention, which may be noticed here.

The shale in the cliff on the north side of the valley of the South Forkof Hay Creek lying 150 feet above the Jurassic, is one that shouldnbsp;have additional collections made from it. It has yielded a large numnbsp;ber of good fossils from a small amount of material, but there are iadinbsp;cations that a careful and prolonged examination would discover manvnbsp;more, probably new ones. The shale is fine-grained and fissile havingnbsp;a light brown color. It preserves the plants beautifully and thev arenbsp;easily worked out of it. It has fragments of plants which with thenbsp;material in hand are not capable of determination, but which hint atnbsp;the existence of forms different from those described. A number ofnbsp;plants found here have not been discovered elsewhere. They occur onnbsp;an important horizon and seem to be very rich in fossilsnbsp;Material occurring at the cliff in the east bank of Oak Creek 2 milesnbsp;below Ilobbio's Eooeb, i,nbsp;nbsp;nbsp;nbsp;In a fl,.e.,...i..e,i,

argillaceous sandstone that is interstratifled with thin layers of a very fine-grained shale. These shale partings preserve plants finelynbsp;and have yielded some very distinct and large imprints. Only a smaffnbsp;amount of material has been obtained from this place. It well denbsp;serves further examination. It occurs on a critical horizon and thenbsp;plants found here do not seem to have suffered so much from driftingnbsp;as they have at most of the other localities.nbsp;nbsp;nbsp;nbsp;�

The bed of �bales at the contact of the Jurassic with the Cretaceous at Lon Cottles Eanch, is another critical horizon, and emineutlvnbsp;deserves further and careful examination. This shale is light chocolatenbsp;in color, very fine grained and fissile, enabling one to work out thenbsp;plants easily. It preserves them finely. It is fmi of fragments ofnbsp;plants, and as the amount of material obtained from it is verv smuJi

cies This shale contains among others the seeds and conerates of AmuccM ^vyom^ngens^s, and the fossils fodnd here do not occSnbsp;elsewhere.

of a� age of ao Hay Creek beds tba ;o boaoath �f� t�P'oal Dakota aaodeto,,. it wi,i be useful to pre

seat] sts of tbe plants that occur on the several horkons. I will beelu With the lowest.nbsp;nbsp;nbsp;nbsp;oegm

Plants occurring at the contact of the Cretaceous with the Jurassic, Division No. 4.

1. nbsp;nbsp;nbsp;Thyrsopteris elliptica Font. ?nbsp;nbsp;nbsp;nbsp;[ 3. Carpolitlxns foenarius Ward u. sx).

Plants occurring on the horizon 100 feet below the Dakota sandstone, Division No. �.

Plants occurring on the horizon 50 to 60 feet below the Dakota sandstone, Division No.S.

Prom these lists it will be seen that the flora of the horizon 100 feet below the Dakota sandstone and that of the horizon 60 feet below it arenbsp;essentially the same. The resemblance is not fully disclosed by thenbsp;lists alone. The same plants that are abundant on the one horizon arenbsp;also abundant on the other, and they show very much the same statenbsp;of preservation. It is noteworthy that on botli of these horizons, fromnbsp;some cause, the plants are more distinctly characterized than they arenbsp;on the lower horizons. They also occur in larger and more completenbsp;specimens, and the leaves are more often attached to stems. The plantsnbsp;indicate that there is no break between the two horizons named, bothnbsp;of which occur in Professor Jenney�s division ilo. 2. The horizon 60 feetnbsp;below the Dakota sandstone is shown by the plants to be somewhatnbsp;higher than that 100 feet below it, in the disappearance of some of thenbsp;survivors from lower horizons, which had struggled on to the latter.nbsp;Thyrsopteris elliptica Font, comes up into the horizon 100 feet belownbsp;the Dakota sandstone, showing one or two doubtful specimens. Itnbsp;does not appear at all on the higher horizon. Gephalotaxopsis magni-folia Pont., surviving' feebly on the lower horizon in division No. 2, doesnbsp;not igt;as8 up into the higher. Pinus siisqimensis Dn. is the only plantnbsp;belonging to the lower horizons that is found on the highest horizon ofnbsp;division No. 2. It should be stated, howevei�, that the specimens supposed to be this Pinus, that are found on the two horizons of divisionnbsp;No. 2, are few and not well characterized, so that the identification ofnbsp;them with P. susquaensis is not entirely free from doubt.

If we compare the list of plants forrnd on the lowest horizon in division No. 2, or that 100 feet below the Dakota sandstone, with that yielded by the horizon 1.50 feet above tlie Jurassic and occurring innbsp;division No. 3, we And a decided change. No dicotyledons occur belownbsp;division No. 2. The plants that are most abundant on the lower horizon in division No. 2, and most characteristic of it, do not occur at allnbsp;below it. Those that come up to it from lover horizons appear as survivors and not as well-established plants. They occur in some cases asnbsp;doubtful forms, and in all cases are rare. Many of the most characteristic j)lants of the lower horizons, such as GzoliaTiowslcia ncTvosd Heer,nbsp;Zamites lorealis Heer, Zamites hrevipennis Heer, do not pass up into thenbsp;horizon 100 feet below the Dakota sandstone. These and othernbsp;evidences derived from a study of the plants indicate a time-breaknbsp;between Jenney�s divisions No. 3 and No. 2. On the other hand, nonbsp;change in the flora of the strata from the junction of the Jurassic withnbsp;the Cretaceous up to the base of division No. 2 indicates a want of conformity in them. Divisions No. 3 and No. 4, so far as the evidence ofnbsp;the plants goes, make one group. It is true that there are changes innbsp;the species occurring on the lower horizons varying from the contactnbsp;of the Jurassic with the Cretaceous up to and including the horizon

150 feet above the Jurassic, but tbe general character of the flora as a whole is the same. It is much more Jurassic in type than that of thenbsp;beds higher up. Thyrsopteris, Zamites (of the type of Z. borealis Heer),nbsp;conifers with flabeilate leaves like Czekauowskia and Baieropsis, Arau-carites and Scleropterids with small pinnules are the most characteristic plants. It must not be forgotten, however, that the collections ofnbsp;plants from these lower beds, especially those of division Ho. 4, arenbsp;very scanty, and far inferior in the number of specimens to thosenbsp;obtained from division Ho. 2. A more thorough search of these stratanbsp;may furnish numerous plants that would materially modify the conclusions drawn from the material now in hand.

GEOLOGICAL AGE OF THE HAY CREEK STRATA LYING BETWEEN THE TYPICAL DAKOTA SANDSTONE AND THE .IITRASSIC.

As stated in the beginning of this paper, the strata yielding the plants described in it were assumed by Hewton to be of the same agenbsp;as the true Dakota, a system of beds in which dicotyledons form nearlynbsp;all the plants, they being of comparatively modern type. The plantsnbsp;found even on the highest horizon of division Ho. 2 differ totally fromnbsp;those of the true Dakota beds, and iudicate a distinctly older series.nbsp;The plants from the two horizons in division Ho. 2 are essentially thenbsp;same and indicate that there is no unconformity in this division. Wenbsp;may leave out of consideration the fusiform markings {Feistmantelianbsp;oblonga Ward u. sp.), the questionable species of Zamites, Baieropsisnbsp;pluripartita Font., and the possible seeds of Leptostrobus, that occurnbsp;on the horizon 100 feet below the Dakota sandstone, for they are toonbsp;poorly characterized to help in determining age. We have then 24nbsp;species from the two horizons of division Ho. 2. Of these, 4 are new,nbsp;and for that reason can not be used in fixing the geological age. Ofnbsp;the 20 species remaining no fewer than 14 occur in the Lower Potomacnbsp;of Virginia. The dicotyledons found in this division are of a morenbsp;modern type than those which occur in the Lower Potomac beneathnbsp;the Brooke or upper jiortion of that group of beds, and Sapindopsisnbsp;variabilis Font., the most abundant dicotyledon in the Brooke strata,nbsp;is by far the most abundant one in division Ho. 2. Besides, such plantsnbsp;as Sphenolepidiiim Kurrianum (Dunk.) Heer, Splienolepiditm parcera-mosum Font., Glyptostrobus broolcensis (Font.) Ward, and Leptostrobusnbsp;longifolius Font., that are common on the Brooke horizon, are commonnbsp;here also.

Of the 20 significant species occurring in division Ho. 2, and not found in the Lower Potomac, G have been previously described as coming from other formations. Finns susquaensis Dn., according to Sirnbsp;William Dawson, occurs in the Kootanie formation; Sequoia gracilisnbsp;Heer, according to Heer, is found in the Rome beds of Greenland;nbsp;Matonidium Althausii (Dunk.) Ward, according to Schenk and Heer,nbsp;occurs in the Wealden of Europe; Pecopteris Gei/leriawa Hath., as stated

by M. Yokoyama, is found in the Xeocoinian of Japan; Weicliselia reticulafa (Stokes and Webb) Ward, Sclieuk gives as occurring in tlienbsp;Urgonian Werrisdorf beds of Europe; Heer gives Fecopteris borealisnbsp;Brongu. as found in the Kome beds of Greenland, wliich he regardsnbsp;as Urgonian in age. The Lower Potomac is, according to the plants,nbsp;Heocomiaii in age. The Wealden being equivalent in age to Lowernbsp;Heocomian, and the Urgonian being a formation of the Upper Heoco-mian, and the Kootaide being also Heocomian in age, it follows thatnbsp;all the fossil plants found in division Yo. ii that are sufficiently wellnbsp;characterized to throw light on its age. are ISTeocomiau species. Of thenbsp;new species, we may omit Uimiphylluni densinerve and Qiiercophyllumnbsp;wyomingensis as being too undetermined to be significant. The twonbsp;remaining ones, Oeinitzia Jenneyi and Gladophlehis wyominge^isis, arenbsp;closely allied to Heocomian fossils.

We may then conclude without hesitation that Jenney's division Ho. 2 is certainly older than the typical Dakota group with predominantnbsp;dicotyledons, and that its age is Heocomian. We may also hold thatnbsp;of the various more or less local groups of beds of Heocomian age, it isnbsp;nearest to the Lower Potomac, as exposed in Virginia. We may gonbsp;further and determine with great probability that the age of divisionnbsp;Ho. 2 corresponds with that of the Brooke group, an upper member ofnbsp;the Lower Potomac.

Coming now to divisions Ho. 3 and Ho. 4, we will not be able to make so satisfactory an analysis, for the fossils are not nearly so well preserved and the specimens are not so large as those of the upper division.nbsp;In addition the collections from these members of the Hay Creeknbsp;series are much more scanty, so that conclusions based on the absencenbsp;of types are more risky than they are in division Ho. 2.

In thetwolowerdivisions32 different species of plants have been found whose characters have been more or less fully determined. Pourteeunbsp;of these are new species, 5 have been found from formations other thannbsp;Potomac, whose age is known, and 13 are Potomac species.

Most of the new species are so regarded because their character has been very imperfectly determined, and not enough is known of them tonbsp;permit their identification with known species. In a number of casesnbsp;there is nothing shown that would prevent more complete specimensnbsp;from exhibiting features that would identify them with plants previously described. Indeed it is quite probable that such forms asnbsp;CarpoUthus fwnarius Ward, Garpolithus harrensis Ward, Zamitesf species, Willkmsoniaf plmnicopsoides Ward, the aments supposed to belongnbsp;to some conifer and some dicotyledons, and the immature cone ofnbsp;Sequoia, are not really new species. The apparently large proportion of new species has then no significance. The new si)ecies thatnbsp;have been determined with some definiteness, such as Araucaritcsnbsp;icyomingensiSj Scleropteris rotundifolia, and Scleropteris ddstantifolia^nbsp;so far as their generic character goes, indicate survivors from the

Jurassic. Thirteen species have been determined, many of them doubtfully, as identical with Lower Potomac forms. They indicate that the beds containing them correspond in age with the lower portion ofnbsp;the Lower Potomac. A number of them are Jurassic in type, beingnbsp;probably survivors of a flora of that age. The large proportion ofnbsp;Potomac species confirms the conclusion deduced from the plants ofnbsp;division �lo. 2, viz, that the flora of the Hay Creek beds is, among thenbsp;local Lower Cretaceous floras, nearest to that of the Lower Potomac.nbsp;Five of the 32 species found in the beds now in question have been previously described as coming from Lower Cretaceous groups other thannbsp;Lower Potomac. Zamites borealis Heer, and Zamites brevipennis Heer,nbsp;were described by Heer from the Kome beds of Greenland, and Sphen-opteris plurinerviaHeev from the Wealden of Portugal. From the latter formation Heer also describes Gzehanoicslcia nervosa Heer. Finnsnbsp;susquaensis Dn., before mentioned, seems more at home in these beds,nbsp;but survives into division �To. 2. Eighteen out of the 32 species arenbsp;then more or less certainly Neocomian species, and they include all thenbsp;plants from these lower strata that are identical with forms previouslynbsp;described.

We find from this review of the plants that all the species of the third and fourth divisions of the Hay Creek beds that lie under the Dakotanbsp;sandstone which can be identified with previously described plants arenbsp;Neocomian in age, and this is a remarkably close agreement between thenbsp;flora of the strata now in question and that of the Neocomian. The factnbsp;that the Hay Creek flora shows a much greater resemblance to that ofnbsp;the Lower Potomac than to the Kootanie floras of British America andnbsp;of Great Falls, Montana, which occur much nearer to the Hay Creeknbsp;region than does the Potomaeof Virginia, is another surprising feature.*

It remains only to consider the forms of plant life that have been obtained from the highest member of the Dakota group of Newton,nbsp;which, there is no reason to doubt, represents some horizon of the truenbsp;Dakota No. 1 of Meek and Hayden, although, in the imperfect state ofnbsp;our knowledge of that formation, it is impossible to fix its j)osition withnbsp;exactness. The rock or matrix in which the plants are embedded isnbsp;wholly different from that of the plains of Kansas where the greaternbsp;part of the plants have been found. No signs of the dark-brown ferruginous sandstones and clay ironstones so characteristic of the latternbsp;were seen by me, and Professor Jenney describes none in the Hay Creeknbsp;region. But it is known that the Dakota group is not wholly made upnbsp;of these, and quite recently heavy beds of different material have beennbsp;found in southern Kansas underlying the typical plant-bearing Dakota

iThis and a number of similar questions are discussed by Professor Jenney in bis notes (see supra, pp. 568-593).

Although there is believed to be unconformity between the true Dakota sandstone of the Black Hills and the Lower Cretaceous bedsnbsp;beneath them, still it is not probable that tlie time interval was verynbsp;great, and therefore it is reasonable to suppose that the Dakota sandstones here represented lie near the base of that formation and correspond rather to some of the � transition beds� of Kansas than to thenbsp;plant-bearing horizons of the plains; and it seems a fair presumptionnbsp;that the latter are wanting in this region. We should not, therefore,nbsp;expect that the flora of these beds would be precisely the same as thatnbsp;which is now so well known as the flora of the Dakota group�that is,nbsp;we should expect it to contain some of the elements of that flora alongnbsp;with some of those of the underlying older floras. This, in fact, isjustnbsp;what the small collection made by Professor Jenney and myself, innbsp;the vicinity of Evans quarry in September, 1893, reveals, and thisnbsp;constitutes all that we thus far know of the plants of the Dakota groupnbsp;in the Black Hills, Professor Jenney not having included any of thesenbsp;in his collection from the Hay Creek region for reasons that he gives.nbsp;We may therefore proceed at once to the examination of these plants.

The study that was made of this collection after my return, by Dr. Knowlton and myself, although characterized as �careful,�^ was not asnbsp;thorough as it might have been, and I am obliged to admit several mistakes in the determinations. Ho figures had been prepared at thatnbsp;time, and it was only in the cases where the nervation was clear that wenbsp;could be certain of its nature. In very obscure and indistinct specimens there is always the liability to mistake meaningless markings onnbsp;the rock for nerves. However it may be with other fossil remains, innbsp;the case of plants, and especially of dicotyledonous leaves with obscurenbsp;nervation, but upon which almost everything depends, it is whollynbsp;unsafe to attempt to determine a collection without drawings, or atnbsp;least pencil sketches, made with the aid of special appliances for finding the nerves and following them out to the margins of the leaves.nbsp;Such drawings have now been made, and with their aid a reexamination of the specimens has resulted in the following determinationsnbsp;which are probably as correct as they can be made from the materialnbsp;in hand.

1 nbsp;nbsp;nbsp;The results of the observations made by me in company with Mr. C. K. Gould were presented innbsp;brief to the Geological Society of Washington on November 10, 1897, and an abstract prepared bynbsp;mj^self was publisbed in Science, X.S,Vot,YI,'N'o. 152, for November 26, 18D7, pp. 814-815 A morenbsp;extended paper by Mr. Gould, entitled � On a series of transition beds from tbe Comanche to the Dakotanbsp;Cretaceous in southwest Kansas,� by Charles Newton Gould, in the American Journal of Science, 4thnbsp;series, Vol. V, March, 1898, pp. 169-175, sums up more fully our joint observations.

DESCTIIPTIO�7 OF THE SPECIES. Subkingdom PTERIDOPHYTA.

Class FILICALES (Ferns).

1874. Asplenmm Dicksonianum Heer: Die Kreide-Flora der arctischen Zone, K. Svensk. Vet.-Akad. Haudl., Vol. XII, No. 6 (FI. Foss. Arct., Vol. Ill, Abtk. II),nbsp;p. 31, pi. i, figs. 1 (excl. b. c._), laa, 2, 3, 3b, 4, 5 (excl. a, b).

Several line specimens of this fern, of which the one �gured is a fair sample, were obtained from the carbonaceous shales overlying the hardnbsp;sandstone at the falls of the Minnekalita Creek or Pall Eiver on thenbsp;right bank.

This plant was first described by Heer from the Kome beds of Greenland (Gault or TJrgonian), but it also occurs in the Atane beds, which are correlated with the Cenomanian, and have been supposed to benbsp;nearly equivalent to the Dakota group. It has been found in thenbsp;Kootanie deposits of British America, in a supposed �Teocomian depositnbsp;at Cape Lisburn, Alaska, and in the Amboy Clays at Woodbridge,nbsp;Few Jersey. It is also one of the few ferns that have been found innbsp;the Dakota group, where, however, it is rare. Its evidence, therefore,nbsp;considered by itself, would be to put even this uppermost deposit innbsp;the Lower Cretaceous, but this is overcome by that of the remainingnbsp;forms. The specimens are the best in the collection, good and characteristic, leaving no doubt on the score of identity. They present anbsp;strong contrast with the few very small and doubtful forms found bynbsp;us on the slope of Red Caiiou and figured on PI. CLXII, Figs. 6, 7, 8nbsp;(see supra, p. 6G4).

Subkiiigdom SPERMATOPHYTA (Phanerogams).

Class DICOTYLEDONE^.

1892. Quercus Wardiana Lx.; Flora of the Dakota Group, Mon. U. S. Geol. Survey, Vol. XVII, p. 53, pi. vii, fig. 1.

These two specimens were collected from the coarse sandstone of bed No. 7 of my section, on jiage 258 of the Journal of Geology for April-

May, 1894, Yol. II, jSTo. 3, reproduced in this paper (supra, p. 500). The one represented by Fig. 2 of PI. OLXX was found iu place over Evansnbsp;quarry, and the one by Fig. 3 in the loose' material thrown down innbsp;uncovering the workable stone, but from the character of the rock itnbsp;undoubtedly came from the same stratum. The rock is too coarse tonbsp;show the finer nervation, and neither specimen shows base, summit, ornbsp;margin. The determination, therefore, as stated on page 262 of thatnbsp;memoir, must remain uncertain. Still, the midrib and secondarynbsp;nerves are very distinct, and agree well with both description and figurenbsp;as given by Lesquereux, while nothing else can be found into which theynbsp;will fit. The general aspect is that of an oak of the type of Q. Prinus L.

1874. Sassafras Miidyei Lx.: Cretaceous Flora, Cputr. Foss. FI. West. Terr. (Hayden), Vol. VI, p. 78, pi. xiv, figs. 3, 4; pi. xxx, fig. 7.

The specimens are all without doubt from bed Xo. 7 over the quarry sandstone at Evans quarry, but those represented by Fig. 4 of PI.nbsp;CLXX and Fig. 1 of PI. CLXXI were found in the debris thrownnbsp;down in uncovering the quarry. These are in coarse, thinly laminatednbsp;sandstone shale, while the other specimen, represented by Fig. 5 ofnbsp;PI. CLXX, came from a clay shale bed in place, which is much flnernbsp;and shows the impression very clearly. The agreement with Les-quereux�s figures is very close, and I have compared it with the originalnbsp;specimens. Our Fig. 4 of PI. CLXX may be compared with Lesque-reux�s fig. 7 of pi. xxx, and our Fig. 5 comes nearest to his fig. 4 of pl.nbsp;xiv. Both of the original specimens unfortunately bear the same number (649) of the U. S. National Museum collection, but they also bearnbsp;Professor Lesquereux�s original numbers, and the former'is his No.nbsp;1349, while the latter is No. 682. They were collected by Mr. Charlesnbsp;Sternberg at Salina, Kansas, in typical Dakota sandstone.

When I studied these specimens for my paper on the Cretaceous Rim of the Black Hills (Jour. Geol., Yol. II, p. 262), I did not make out thenbsp;nervation on the coarse sandstone of the two specimens now shown innbsp;Fig. 4 of PI. CLXX and Fig. 1 of PI. CLXXI, and from the generalnbsp;form I identified them with Lindera venusta of Lesquereux. This isnbsp;now seen to have been an error. I also wrongly supposed that thenbsp;specimen Fig. 5 of PI. CLXX was the same as the others that Inbsp;had referred to Aralia Towneri Lx., and so placed it. On careful comparison of the figures and specimens it is obvious that none of themnbsp;represent that species, and that they differ generically from one another.

1892. Platanus cissoides Lx.: Hora of the Dakota Croup, Mon. U. S. Geol. Survey, Vol. XVn, p. 75, pi. Ixi, fig. 3.

This is only a fragment, but so far as it goes it agrees witli the specimen figured by Lesquereux. It is in a fine-grained clay shale, which shows the nervation clearly. I referred it doubtfully to this species innbsp;my early paper, and now, after a drawing has been made and the matter has been subjected to a reexamination, I find myself unable to suggest anotlier reference. It is a question of letting it stand or rejectingnbsp;it entirely, and as it is clearly diiferent from anything else obtained, Inbsp;incline to the former course. It was found in place over the quarrynbsp;sandstone at Evans quarry.

Leaves elliptical in outline, 4 to 6 cm. long, about 3 cm. wide, crenate-dentate with rounded teeth to near the base, petioled, oblique at base, the lamina extending lower on one side, rounded at the summit] midrib strong, more or less curved; secondary nerves about 6 on a side,nbsp;rather distant, irregularly placed, leaving the midrib at an angle ofnbsp;about 45�, curving upward, the lower more than the upper, so as tonbsp;converge in crossing the blade, slightly undulating or irregular in theirnbsp;course, giving off a few tertiary nerves or nervilles from both sides,nbsp;which sometimes join some distance from the margin and form an angular arch or loop, from the outer part of which small nerves proceed intonbsp;the teeth, sometimes forking or dividing, the branches entering thenbsp;teeth.

Fig. 3 of PI. GLXXI represents a specimen from the clay shales above Evans quarry, consisting of the lower part of two leaves lyingnbsp;side by side, with petioles complete. Considerably more than half ofnbsp;one of them is preserved and one side of the other, showing the nervation clearly. In searching for the equivalent of this form I have beennbsp;unable to find it in the Dakota group, and, indeed, I have thus farnbsp;failed to find anything similar in any published illustrations. That itnbsp;represents a Oelastrophyllum is clear both from the characteristic nervation and from the general facies, and a large number of siiecies of that

genus have been described from different formations ranging from the older Potomac to the Miocene. In the Potomac formation, as I havenbsp;previously shown,' it constitutes one of the most complete series thatnbsp;we have rising with slight modifications from one horizon to another,nbsp;from the lowest to the highest beds. Many of these forms have beennbsp;described and figured, but others remain unpublished. I have studiednbsp;them all more or less, and I remembered one species in particularnbsp;obtained by me from the Aquia Creek series at Port Foote, Maryland,nbsp;in a bluff on the bank of the Potomac, to which I had given specialnbsp;attention and of which pencil sketches had been made to enable me tonbsp;make out the exact nervation. This I knew must be close to the formnbsp;in question, and when I comx)ared it I found them substantially identical I had gone so far as to name the Potomac form Gelastrophyllumnbsp;pulciirum on the labels without having as yet written the description.nbsp;The agreement is so close that there seems no course left but to consider the Black Hills plant as the same as the Maryland one, and Inbsp;here introduce one of the figures already prepared (Fig 4. of PI.nbsp;OLXXI) for comparison. The difference in the horizon points, alongnbsp;with other facts, to a low position in the Dakota series for the bedsnbsp;in question.

Family VITAGEH51 (Vine family).

187�? Sassafras obtusus Lx.; Fifth Ann. Rept. U. S. Geol. Surv. Terr. (Hayden) for 1871, p. 303.

1873 nbsp;nbsp;nbsp;Sassafras obtusus Lx.: Sixth Ann. Rept. U. S. Geol. Surv. Terr. (Hayden) for 1872,

1874 nbsp;nbsp;nbsp;Sassafras obtusum Lx.; Cretaceons Flora, Contr. Foss. FI. West. Terr., Pt, I,

1870. Cissites obiusurn I,x.; Eighth Ann. Rept. U. S. Geol. Surv. Terr. (Hayden) for 1874, p. 354.

1883 Cissites salisburinfoUus Lx.: Cretaceons and Tertiary Flora, Contr. Foss. FI. West. Terr., Pt. Ill, Rept. IT. S. Geol. Surv. Terr.� (Hayden), Vol. VIII, p. 66.

This flue specimen was found at the falls on the right bank of Min-nekahta Creek or Fall River, below Evans quarry, in the shales over-lying the hard sandstone, associated with Asplenium Diclcsoniamim Heer, already recorded. The shales were so thin that they broke intonbsp;a number of jiieces, which were carefully jireserved, so that on examin-ino- the material it was possible to find an almost complete leaf, and fornbsp;a large part of this both surfaces (counterparts) ar� present. It proves

to be one of the most beautiful specimens that have thus far been found of this species.

In studying the broken pieces before they had been put together and a complete figure made, I was led to compare it with Aralia Tou-nerinbsp;of Lesquereux, to which it bears some resemblance, but upon a reinvestigation I am satisfied that it is not that plant, which does not occurnbsp;in the collection.

Our form has the very rounded lobes of those represented in the Cretaceous Flora, pi. xiii, and though considerably larger, most closelynbsp;approaches figs. 2 and 3 of that plat e. There is the same tendency ofnbsp;one of the lateral primaries to curve outward more than the other thatnbsp;is seen in fig. 3, only this is still more marked.

The general question as to whether plants of this type from the American Cretaceous are really the ancestors of the exclusively American genus Sassafras, or should be referred to the vine or the planenbsp;trees, need not be discussed here. It will suffice to refer to two of mynbsp;early papers on the subject published in 1888 and 1890, respectively.*

1892. Cissites iiujens Lx.: Flora of the Dakota Group, Mon. U. S. Geol. Survey, A^ol.

The specimen represented by Fig. 1 of PI. CLXXII was collected at the falls on the right bank of Minnekahta Creek or Fall Elver in thinnbsp;shale, which was rather coarse and had very uneven partings, rendering the collection of specimens unsatisfactory. The nervation isnbsp;obscure. The other specimen, Pig. 2, is one that was picked up in thenbsp;debris at the foot of the cliff below Evans quarry and must have comenbsp;from bed Xo. 7. It is somewhat more clear in its nervation, but thenbsp;upper part of the leaf is wanting and none of the lobes or sinusesnbsp;remain. I had labeled it Aralia Towneri, and it is possible that it maynbsp;represent Sassafras Mtidgii, but I seem to see a difference in its generalnbsp;aspect from the other specimens so referred. Both these specimens, sonbsp;far as they go, agree almost perfectly with Cissites ingens Lx., as shownnbsp;by the perfect specimen figured on pi. xix, fig. 2, of the flora of thenbsp;Dakota group. This conformity extends in both cases so far as tonbsp;include the rather unusual feature seen in the opposite secondary nervesnbsp;of the midrib or middle primary. I think there is good reason tonbsp;believe that both these leaves belong to the same species as those figured by Lesquereux from the Dakota group of Ellsworth County, Kansas, but whether they are ancestors of the vine or of the plane tree isnbsp;a much more difficult question.

iProc. TJ. S. Xat. Mus., Vol. XI, pp. 39-42, pi. xvii-xxii, 1888; Araericaii Katuralist, Vol. XXIV, September, 1890, pp. 797-810, pi. xxviii.

Leaves coriaceous, oblong, rounded at the summit, subcordate or truncate at the base, entire or slightly denticulate, pinnately nerved,-midrib strong, straight or slightly eurved; secondaries thick, rathernbsp;near together, approximately parallel, straight or slightly curvingnbsp;upward, somewhat irregular in their course, closer on one side of thenbsp;midrib than on the other and making a different angle with it, this anglenbsp;varying from 30� near the summit, where they curve in toward thenbsp;apex, to 60� near the base, some of them forking and others simple,nbsp;the dichotomy sometimes taking place near the margin and sometimesnbsp;near the middle of the nerve; nervilles distinct and numerous, many ofnbsp;them percurrent, but others joining and anastomosing to form triangularnbsp;or rectangular meshes.

In my early paper I did not give the full character of this species, but only pointed out its relation to the only other two species of thenbsp;genus. Professor Lesquereux, as appears from Dr. Knowlton�s footnote to page 124 of the flora of the Dakota Droup, recognized thenbsp;resemblance of the forms for which the genus was established to Prp-tophyllum, and had he not made the genus Viburnites I should havenbsp;been obliged to refer these forms to Protophyllum. The difference isnbsp;perhaps not generic, and it is an interesting question whether it pointsnbsp;to a real relationship between the fossil Viburnums and Protophyllum.nbsp;There is scarcely a doubt as to the correctness of the reference of manynbsp;of our fossil leaves to Viburnum, and I have found seeds of Viburnumnbsp;associated with such leaves.^ The similar nervation of many speciesnbsp;of Protophyllum, and especially the strong dichotomy of the secondarynbsp;nerves, has always suggested to me an affinity between these genera.nbsp;As the systematic position of Protophyllum has always been a matternbsp;�of speculation, this possible connecting link in Viburnites has a specialnbsp;interest for the botanist.

Both the specimens were found in place in the shales above Evans quarry, bed No. 7 of my section.

I take pleasure in repeating the statement formerly made, that the specific name chosen for this plant was meant to give some slightnbsp;expression of my appreciation of the favors extended to me and mynbsp;party by Mr. Pred. Evans, of Hot Springs, the leading citizen of thenbsp;town, proprietor of Evans�s quarry, and a public spirited and generousnbsp;man.

1 Types of tbe Laramie Flora, Hull. U. S. Geol Survey, Ko. 37, 1887, p. 109, pi. 11, figs. 4-8.

Under the four preceding heads there have been described 87 distinct forms of plant life from the Cretaceous deposits of the Black Hills, viz,nbsp;22 in the condition of silicifled cycadean trunks without foliage, 1 innbsp;the condition of silicifled wood belonging to the ConifeiiB, 57 in thenbsp;condition of impressions upon the sandstones and shales of Lower Cretaceous rocks of stems, leaves, and fruits, and 8 in the same conditionnbsp;as the last occurring in rocks of the Dakota group proper, or Uppernbsp;Cretaceous. One of these latter, Asplenium Dicksonianum Heer, occursnbsp;in both these beds, which accounts for the otherwise apparent increasenbsp;in the number to 88 instead of 87.nbsp;nbsp;nbsp;nbsp;,

Professor Fontaine has given, at the close of his treatment of the Hay Creek flora (supra, pp. 699-702), a fairly complete summary ofnbsp;the general results of a study of these plants, and as this constitutes thenbsp;great bulk of the entire flora, there is little to add by way of correlation.

Professor Jenney has also discussed certain questions arising out of the geological and geographical distribution of the plant remains, having been furnished with a copy of Professor Fontaine�s report in manuscript. Itoccurred tome, however, thata table showing the distributionnbsp;of all the plants, not only within the Black Hills, but throughout thenbsp;American beds, and also in other countries wherever species previouslynbsp;known have been identifled in the Black Hills, would afford any whonbsp;might be disposed to do so an opportunity to make general comparisons and to better understand the full meaning of the data presented.

� It will be observed that the above table is divided into two principal parts, viz; First, that containing the distribution within the Blacknbsp;Hills; and, secondly, the outside distribution of the species that are notnbsp;new. So far as the Hay Creek species are concerned. Professor Fontaine has sufficiently dwelt upon the remarkable features of the distribution, especially the great number that are common to those beds andnbsp;the Potomac formation. He has also discussed the value from a paleontological point of view of Professor Jenney�s stratigraphical subdivisions, I will only say on this last head that after a careful comparisonnbsp;of his sections with those that were made by us conjointly in 1893, Inbsp;have decided that the plant bed which we discovered on the easternnbsp;slope of Red Canyon, a short distance west of the principal fossil forest,nbsp;some 3 miles southwest of Minnekahta station, 50 to 75 feet above thenbsp;Jurassic, and constituting No. 9 of our flrst section (Jour. Ceol., Vol.nbsp;II, p. 255), must come within his division No. 4, while the principalnbsp;cycad bed. No. 12 of that section, which lies 175 to 200 feet above thenbsp;Jurassic and about 60 to 100 feet below the base of the Dakota sandstone, which is eroded away in that region, probably comes within hisnbsp;division No. 2, and is so treated in the table. The position of the cycadnbsp;bed in the Blackhawk region has also been carefully studied, and isnbsp;found to occupy the same relation to the underlying and overlying

strata as that of Miiuiekahta. I have therefore assumed that all the cycads come from No. 2, a couclusion which is subject to futurenbsp;correction.

Other forms of cycadaceous vegetation are very scarce, only three undoubted species of that type occurring in the collection. Two ofnbsp;these, Zamites brevipennis Heer and Z. borealis Heer, are from the Haynbsp;Creek region, and, as Professor Jenney in one of his letters remarks,nbsp;these were, found in divisions No. 3 and No. 4. The Olossozamites Fon-taineanus found by us in Ited Canyon is also referable to No. 4. Ifnbsp;these are the leaves of the plants whose trunks occur in such greatnbsp;abundance the two ought to be found at about the same horizon. Still,nbsp;so meager is the present known flora that no conclusions drawn from itsnbsp;absence in certain beds can be considered valid. The further fact, alsonbsp;pointed out by Professor Jenney, that tlie principal cycad bed is nearlynbsp;100 miles south of the Hay Creek region may possess some significancenbsp;for the vertical distribution.

A glance at the first part of the table serves chiefly to impress the mind with the defectiveness of the record, and the somewhat orderlessnbsp;grouping of the marks in certain parts of the pages can scarcely benbsp;said to furnish a basis for discussing the range of the species. As itnbsp;stands, however, it may be said in general that while most of the fernsnbsp;occur in divisions No. 3 and No. 4, most of the true conifers are found innbsp;division No. 2, and well up in that. The Taxacete and Ginkgoalesnbsp;occupy a somewhat intermediate position in No. 3.

The number of forms common to the Black Hills Lower Cretaceous and the Potomac formation greatly exceeds those common to it and thenbsp;Kootanie; but it must be remembered that the present known Potomacnbsp;flora is many times greater than the Kootanie flora as now known, andnbsp;it is probable that this difference would be equalized were we in possession of all the data for comparison. A few species occur in thenbsp;Amboy Clays, Tuscaloosa formation, and Island series, i. e., in thenbsp;Newer Potomac, but these are not sufficient to warrant us in assumingnbsp;that any of the plant-bearing beds of the Black Hills thus far found arenbsp;the equivalent of these upper beds. On the other hand, as I havenbsp;already pointed out (supra, p. 703), the small flora known from the Dakotanbsp;sandstone above Evans quarry and at Minuekahta Falls indicates anbsp;very low place for these beds in the true Dakota group, and would notnbsp;be wholly inconsistent with their reference to the horizon of the Cheyenne sandstone or lower Albirupean.

The distribution outside of America is principally confined to the Lower Cretaceous, especially the Wealden and Neocomian, which arenbsp;probably for the most part parallel series, the name being dependentnbsp;upon the character of the deposits, the IVealden being the estuarine ornbsp;lacustrine equivalent of the marine Neocomian of various countries. Itnbsp;is further significant that all the species of wide lateral and verticalnbsp;range, Weichselia reticulata, Matonidium Althausii, Sequoia Beichenbachi,

and Spehnolepidium Kurrianum, which make up the bulk of the foreign distribution, are primarily Wealden or Keocomiau species, and theirnbsp;range above and below is merely the result of the great abundance,nbsp;exuberance, and persistence of these forms, or in part, perhaps, ofnbsp;errors in determination.

I have frequently alluded to these facts and have given the distribution of the same and other similar forms occurring in the Lower Cretaceous of America,^ and my only excuse lor repeating them here, in so far as they concern this paper, is that I desire to make the evidence asnbsp;complete as possible, and omit nothing that in any important degreenbsp;bears upon the age of the beds yielding the flora here recorded. To anynbsp;one competent to weigh this evidence there should no longer remainnbsp;a doubt on the general subject, and alike the original claim that allnbsp;the sandstones of the Cretaceous rim of the Black Hills belong to thenbsp;Dakota group proper, or Ko. 1 of Meek and Hayden, and the recent contention that the cycad and other plant-bearing beds form a part of thenbsp;Jurassic may be regarded as definitively overthrown.

^See Am. Jour. Sci., 3d series, Vol. XXXVI, August, 1888, i).127; Fifteenth Ann. Rept, IT. S. Geol. Survey, pp, 388-392; Sixteenth Ann. Rept. U. S. Geol. Survey, Parti, pp. 482-483.

	1									Distribution within the			Black Hills.
	'													Division No. 2.							Division No. 1.
							Division No.		3.
	1						Division No.		3.										60 feet below		Dakota pro]	group )er.
	j	Jurassic contact.	50 feet above the Jurassic.		50-75 feet above the Jurassic.		150 feet above the Jurassic.									sands	one.		the D sands	akota tone.	Dakota pro]	group )er.
	17ames of the species.			quot;o 3Q es tD 5		-�o ?; P	� �		43 P' o � o	ca 75 '� �	� P p	43 o w �*3 o	% i ^ i *0 1	�4. o � �	� c � p	� � � � p �-1	pa � p 2 a Z		M � . � .P O p	� �	� p p 3 � .			c4 1 'p c	C8 �
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a		JO	, g	O		P	' b	43			�					43	O	�				� gt;	�*. �	�	c	.5
V rt g		o O P	CO	� pg 75	*� � fO ct t-l p	� . o � � �� '3nbsp;o'*� OP�	p �	cS pq p	�:� p �	� g � �	� 1 o	U c � � p pa H	1 rt	S c lt;?	p � 5	c � 5	o ?H o	p	� g �	c	� � 73	� -S fP X	�w 'E	g o o w	� � amp;	�
							CC	�	O	H		U c � � p pa H												�
									O				1		X	........	........	.........	........
�									X				...........			X	X	X	X 1
1	Equisetum A�irginicum Font..................................................	........		........					X				...............		X	.....	........	X	1		........	........
2	Weichselia reticulata (Stokes and Webb) Ward..............................					........	........1	.......	.......			...	...............				X	X		- -.	........	........		.....
3	Matonidium Althausii (Dunk.) Ward.........................................				........		........1			.......		....	...............					X			........	........		.....
4	Pecopteris Geyleriana Nath..................................................					.......	........		.......	.......	....								X j	.......	........	........
5	borealis Brongn...................................................	.......					........	.......	.......	.......		.......	.......	.......					X j	.......	........	.......	......
6	Cladophlebis wyomingensis n. sp.............................................	.......		.......			........			.......			.......	... - �			........		!.......		.....* * *	........		X
7	parva Font.....................................................	.......				.......		.......	X	.......		.......	.......					........	1				......		......
8 '	Sphenopteris plurinervia Heer (?)............................................		.......	.......	.......	.......	........	.......	X	.......		.......							1				......		......
9	Thyrsopteria pinnatifida Font (?)............................................	.......	.......	.......		.......	........		X	.......		.......	.......				........	........					......	.....		.....
10 i	crassinervis Font...............................................	.......	.......	.......	.......	.......	........	.......	X	.......		.......					........	........	........					.....	......
11	elliptica Font...................................................	X	.......	.......		.......	X	.......	X	.......					........	........			.....	........	........	.......		X	......
12	dentifolia n. ap..................................................	.......	.......	X		.......	........	.......	.......	.....						........						.......		X	......
13	brevifolia Font.................................................	.......	.......	X	.......			.......	........	.......					........	........	........				........	.......
14	pecopteroides Font.............................................	.......		X		.......				........					........	........	........		......	........	........	.......
15	brevixienids Font...............................................		.......	........	........	........		........	X	.....*quot;		........	........		........		........		........	........	........			***��.	......	.....
16	Scleropteris distaiitifoNa n. sp................................................		........		........	........	�	........	X	........			.......		........	........	........	........		........	X	.......			......	.....
17	rotundii'olia n. sp................................................		.......	........	........	........	........	........	X	..-��***	1	........			........		........	........		...............		.......			X	X
18	Asplenium Dicksonianum Heer ..............................................	........	........	........		X	........	........	........	...?'*	...	........	........	X		........	........	........		...............		.......			......	.....
]9	Gleichenia Zippei Heer (?)...................................................	........	........	........	........	X		........	........	........	X	........			........		........		........		........	.......			......
2U i	Cycadeoidea dacotensis (McBride) Ward emend..............................		........	........		........		........	........			........			........		........	........	........	........	........	.......			......
21	colossalis n. sp...................................................	........	........	........	........		........	........	........			........			........	.......	........		........		........	.......			......
22	Wellsiin. sp.....................................................	........	........	........	........	........		........	........		.J				........		........		........		........	.......			......
23	ininnekabtensis n. sp........................... ................	........	........	........		........	........		........	X	'	.......							........	........
24	I)ulcherrima n. sp................................................	........				........		........	........	X		........	X	A�	........				........	........	........	.......
25	cicatricula n. sp.................................................	........	........			........	........		........	........	...	........				........	.......		........	........	........	.......
26	turrita n. sp.....................................................		........	........		........		........	........			........				........			........	........		.......			......
27	McBridei n. sp..................................................	........		........		........	........	........	........	X			.....'		........		........		.......	........		.......	��		......
28	Marshiaua n. sp.................................................			........	........	........	........	........	........			........										.......
29	furcata n. sp.....................................................		........	........		........	........					... ----	......	.....1........						........	........	.......
30	Colei n. sp.......................................................	........	........		........	........	........	........	........	X		........	X	........1........							........	.......
31	Paynei ........................................................	........	........	........	........	........	........	........	........			........		........												......
32	aspera ii. sp......................................................	........	........	........		........	........	........	........	.......		........		.....	........				........							......
33	insolita n. sp....................................................			........			.........	........	........				' X	.....	........		........			........	......* �					......
34	occidentalis n. sp................................................				........			........	........	X		........	' X	.....	.......						........				......	......
35	Jenneyana Ward................................................	........	........	........	........		........	........	........	X		........	X		........							.......
36	ingens n. sp.....................................................			........	........				........	........		........
37	fonuosa n. sp....................................................	........		........		........		........	........			........
38	Stillwelli n. sp...................................................	........		........	........	........	........	........	........	X		X								.....* � *						......
39	excelsa n. sp.....................................................	........		........			........			........		........	.....
40	nana n. sp.......................................................		........	........	........	........		........	........	X			quot;..... .......								........	.......
41	Zamites brevipennis Heer....................................................	........	........	........	........	........		X	........	........			.......							......	........			X	......
42	borealis Heer........................................................	........	X		X	........	........	X	........	........		........	.....				X				� * *.....
43	(?)8p. Font..........................................................	........	........	........	........	........	........	........	........	........				........			X						X		......
44	Glossozamites Fontaineanus Ward n. sp......................................		........		----....	X	........	........	........	........				.......		........						.......		(!)		......
45	Cycadeospermum rotundatum Font...........................................	........	........	........	........		........		........	........					........											......
46	WilJiamsonia (?) phcenicopsoides Ward n. sp.................................		........	........	........	........	........	........	X	X									.....						......	......
47	Araucarioxylon Hoppertonae Kn. n. sp........................................	........	........	........		........	........	........	........	X					X		.....		X		........	.......			......	......
48	Araucarites wyomingensis n. sp..............................................	X	........	........	........	........	........		X					........	X				X					***'t .	......
49	(?) cuneatus Ward n. sp..........................................	........	........	........	........		........	X		........							X		X		......				X	......
50	Pinus susquaensis Dn........................................................		X	........		........	X		........	........			�' '		X			' ' '							......	......
51	Abielites angusticarpus Font.................................................	........			........	.......	........	........		........				........	X	........			X	' 1........					X
52	Leptoatrobus longifolius Font................................................						........	.......	........	........								........	X		.......				......	......
53	alatus Ward n. sp. -.............................................		........	........	........		........	........		.......								.......	_____							......
54	AthrotaxopsivS tenuicaulis Font...............................................	........		........	........	.......			........	........		.......'			X				........					X	......
55	Sequoia Eeichenbachi (Gein.) Heer...........................................	........	........						.......									.......	X					X	......
66	gracilis Heer.........................................................			........					.......	........				........		X	X�	.......	X					��v..	......
57	sp. Font, (immature cone)............................................	........	........			.......	.......		X								.......	.......	X	1 .....				**��. .	......
58	Geinitzia Jenneyi n. sp........................................................	.......	........	........	.......				.......								.......	.......	X	1					......	......
59	Sphenolepidium Kurrianum (Dunk.) Heer....................................		........	.......			.......	.......	.......					.......			.......		1	..... .....					......	......
60	parceramosuin Font..........................................	........			.......	.......		.......	.......	.......					......			.......	1...'.....	1					......
61	Glyptostrobus brookensis (Font.) Ward......................................	........	.......		.......	.......	.......	.......		.......					.....		.......	.......		I		i� � *.			......
02	Nageiopsis longifolia Font....................................................			.......	.......	.......	X	.......	X	.......							.......	1.......	.1...	1					......	......
63	angustifoliaFont. (?)..............................................	.......	.......	.......	.......	.......	X	.......		.......							.......		!.......	......					......
64	Baieropsis adiantifolia Font..................................................	.......	.......	.......		.......	X		X			......*		.......					.......	...... 1					......	......
65	pluripartitaFont (?)..............................................	.......	.......	.......		.......	X		.......	.......	...			.......			.......		.......	...... !					......	......
66	Czekanowskia nervosa Heer..................................................	.......	X	......^	.......	.......	X	.......		.......						...	.......	!.......								......
67	Cephalotaxopsis magnifolia Font.............................................	.......	.......		.......	.......	X	.......	X	.......							.......	1.......	.......	......,J		� �..	**�			......
68	Male ament of a conifer....... .......................................-......		.......			.......	.......	.......	X	.......					�. * �	.....	.......	! X		........i		X
69	Qvrercophyllum wyomingense n. sp.......................................	.......			.......	......			.......	.......				.......	quot;quot;	.....	.......		X	.......J		* �..		***�..	......
70	Quorcus WardianaLx. (?)...................................................						.......	.......	.......	.......						!.......	........			.......!				***��.
71	Ulmiphyllum densinerve n. sp................................................	.......		.......	.......	.......			.......	.......	...				quot;quot;		.......		1.......	........		X	**�	***��	......
72	Ficophyllum serratum Font..................................................		.......		.......	.......	.......	.......									.......	.......	(.......			X			......
73	Sassafras Mudgii Lx.........................................-...............				.......		.......	.......									X	.......	! �			X
74	Platanus cissoidcs Lx, (?)....................................................				.......		.......		.......	.......						.......	.......	.......		.......
75	Colastrophyllum pulcbrum Ward n. sp......................................			.......				.......		.......					�		.......	.......	.......		X	'.......
76	Sapindopsis variabilis Font..................................................	.......		.......			.......	.......	.......	.......							.......	.......	.......			. X
77	Cissites aalisburiiSfoUua Lx..................................................	.......		.......				.......	........	........		^,...''					.......	.......	.......	.......		; X			___...
78	ingena Lx...........................................................	.......			.......			........	........	........				.......			.......		1.......	.......		.........			......	......
79	Viburnites Evansanus Ward................................................	.......	........j.......			.......		.......	........	........						J.......	.......		.......	.......		.......			......
80	Male ament of a dicotyledon.................................................	.......			.......		........	.......	X	.......						.j.......		.......	.......	.......	�.				......	......
81	Carpolithus fasciculatus Font...............................................	.......			........		........	........	X	.......					X	.......		........	........	.......					......
82	montium-nigrorum Ward n. sp..................................	.......			.......	........	........	........	X			......'	� quot;*					........		.......		i �*				......
83	barrensis Ward n. ap............................................	.......	.......	.......		........	........	X	.......	. ... ^					X	1.......	.......	........						X		......
84	vtrginiensis Font...............................................	.......	........	........	........	........	........	........	........	.......			..			�- nbsp;nbsp;nbsp;�						I			......
85 86	fcenarius Ward n. sp............................................ Feistmantelia oblonga Ward n. gen. n. sp.....................................	X	.......	........	........	........		........	........	........	........														......	......
85 86


				Upper Cretaceous,									Jurassic.
� � t. � n 1 � H	i 1 43 cz n � P � P M o ��g iz; rs O o 1 5	�' Ml o 'o � � �g o a	� 5 p � si � P cS . MJ � O u -P � P si a	rP P *P g	1 '� H� M � gt; 3 o � P sz r*	M � �E � M . � P gt; �nbsp;�Equot;quot; � p � p p � � p � Pm	p .2 �E � S *�} � � r� S ' quot;�	si B � � quot;S � o M � �	p p �? p c % p o � tfi �S '	p p c � s o i O bD P �E P. t/i	? p p 1	i ^ p d	p � d si p w	quot;o O � M M O	�� � c � M O	1 � a � quot;p M Ph	_p p d � � � � ^3
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quot;VVealden.

	r 1	Distribution within the
	r 1	Division No. 4.					Division No. 3.			175-�
(h 4/ ,0 s p p 0 1 �S 02	i Names of the species.	Jurassic contact.	50 feet above the Jurassic.		50-75 feet above the Jurhssic.		150 feet above the Jurassic.			175-�	00 feet aboTe the Cycad beds
(h 4/ ,0 s p p 0 1 �S 02	i Names of the species.	4 P ei Tsi � O P o	4 � m �	o � P O (C 00 � . Sg � � � gt; o agt; �	42 cd JS � � � � .a cS b P, h!	W ei l-i ei P O.S c. o O quot;� P fe ' 4^ p � o ga� P-^ OP�	A a � o � 'p P p 'P � .55 u A a � p �	quot;� p p � p w p � �-5	p: 4^ P � � sh O ,2 � � P U ^ P 3	p P P P s quot;o � p o o p � 0 � '3 � 2 .p H	quot;p � p p S � . 4^ B 2 44gt; � P � � ffi � a �	43 o w �M o � � s � o bfinbsp;�,P ll � i � � t-i
1	Equisetura virginicum Font..................................................							.......	X	.......	.......	........
2	Weicbselia reticulata (Stokes and Webb) Ward..............................	........				........			.......	.......	.......
3	Matouidium Althausii (Dunk.) Ward.........................................									.......	.......
4	Peeopteris Geyleriana Nath..................................................			........		.......	.......		.......	.......
5	borealis Brongn...................................................						.......	.......	.......	........	.....
6	Cladophlebis w^'oniingensis n. sp.............................................			.......			.......	.......		.......	quot;quot;
	parva Font.....................................................	.......				.......	.......	.......	X
8 '	Sphenopteris plurinervia Heer (?)............................................		.......	.......	.......		.......		X	........
9	Thyrsopteris pinnatifida Font (?)............................................	.......	.......	.......					X	........		.......
10 i	crassinervis Font...............................................	.......	.......	.......	.......	.......	.......	.......	X	........		.......
11	ellixitica Font.................................................. �	X	.......	.......		.......	X	.......	X	........
12	dentifolia n. sp..................................................		.......	X		.......	.......	.......	.......	........
13	brevifolia Font.................................................	.......		X	.......	.......	.......	.......	.......			.......
14	pecopteroides Font.............................................	.......		X	......^	.......	.......	.......	�
15	brevijjeniiis Font...............................................	.......	.......	........	.......	.......	........	........	X	........
16	Scleropteris distanlitoNa n. sp................................................			.......	.......	........	........	........	X	........		.......
17	rotundifolia n. ap................................................	........	........	........	.......	........	........		X		_j	........
18	Asplenium Dicksonianum Heer..............................................	........	........	........		X	........	........	........	........	.J	........
19 ;	Gleichenia Zippei Heer (?)...................................................	........	........	........	........	X		........	........	........	X j	........
20 1	Cycadeoidea dacotensis (McBride) Ward emend..............................		........	........	........	........	........	........	........		.J	........
21;	colossalis n. sp...................................................	........	........	........	........	........	........		........		j	........
22	Wellsiiii. sp.....................................................	........	........	........	........	........		........	........	X
23	luinnekahtensis n. sp............................................	........	........		........	........	........	........		X	..i	........
24	pulcherrima n. sp................................................	........			........	........	........	........	........	X		........
25	cicatricula n. sp.................................................	........			........	........	........		........	........		........
26	turrita n. sp.....................................................		........			........	........	........	........	X		........
27	McBridein.sp..................................................			........			........	........	........	X
28	Marshiana n. sp.................................................		........	........	........	........	........	........	........	X		........
29	furcata n. sp.....................................................		........		........	........	........		........			...----
30	Colei n. sp.......................................................	........			........	........	........		........	X
31	Paynei n. sp....................................................	........	........	........	........	........	........		........
32	asperan. sp.........................i............................	........		........	........	........		........	........	........
33	insolita ii. sp....................................................		........	........	........
34	occidentalis n. sp................................................		........		........	........	........		........	X		........
35	Jenneyana Ward................................................			........	........		........	........	........	X
36	ingens n. sp.....................................................		........	........	........				........	........
37	foriiiosa n. sp....................................................	........		........		........	........	........	........	........
38	Sfcillwelli n. sp....................................................	........		........		........	........	........	........	X		X
39	excelsa n. sp.....................................................			........		........	........			........
40	naua n. sp.......................................................		........	........	........	........	........	........		X	'
41	Zamites brevipennis Heer....................................................	.....	........	........	........	........		X	........	.....
42	borealis Heer........................................................	........	X		X	........	........	X	........	........
43	^ nbsp;nbsp;nbsp;(?)8p. Font..........................................................	........		........	........	........	........	........	........	........		........
44	Glossozamites Fontaineanus Ward n. sp................................... - -.		........		........	X	........	........	........	........
45	Cycadeospermum rotundatum Font...........................................	........	........	........	........	........	........		........	........		......quot;
46	Williamsonia (?) pbcenicopsoides Ward n. sp.................................		........		........	........	........	........	X	........
47	Araucarioxylon Hoppertonse Kn. n.sp........................................		........		........	........	........	........	.......	X
48	Araucarites wyomingensis n. sp..............................................	X		........	........	........		........	X	.......
49	(?) cuneatus Ward n. sp..........................................	........		........	........	........	........	X	.......	........
50	Pinus susquaensis Dn........................................................		X	........	........	........	X	........	........	........
51	Abielites angusticarpus Font.................................................				........	........	........
52	Leptostrobus Jongifolius Font................................................		........	........	........	........	........		.......	........
53	alatus Ward n. sp...............................................	........	........	........	........			........	.......	.......
54	Athrotaxopais teniiicaulis Font...............................................	........				........	;.......	........	.......
55	Sequoia Reicbenbacbi (Gein.) Heer...........................................	........	........	........					.......	.......
56	gracilis Heer.........................................................				........	........			.......	.......
57	sp. Font, (immature cone)............................................	........			........	.......	.......		X
58	Geinitzia Jenneyi n. sp........................................................	.......	........	........	.......	.......			.......
59	Sphenolepidium Kurrianum (Dunk.) Heer....................................	........	........				.......	.......		.......
60	parceramosum Font..........................................	........	.......		........	.......		.......	.......	.......
61	Glyptostrobus brookensis (Font.) Ward......................................	........	.......		.......	.......	.......	.......	.......
62	Nageiopsis longifolia Font....................................................				.......	.......	X	.......	X
63	angustifoliaFont. (?)..............................................	.......	.......		.......	.......	X		.......	.......
64	Baieropsis adiantifolia Font.................................................			.......		.......	X		X	.......
65	pluripartitaFont (?)..............................................	.......	.......	.......		.......	X	.......		.......
66	Czekanowskia nervosa Heer.................................................	.......	X	......-			X			.......
67	Cepbalotaxopsis magmiolia Font............................................		.......			.......	X		X	.......	....
68	Male ament of a conifer.....................................................		.......	.......	.......	.......	.......	.......	X	.......
69	Quercopbyllum wyomingense n. sp.......................................	.......			.......	......	.......	.......	.......
70	Quercus Wardiana Lx. (?)...................................................	.......	.......	.......					.......	........		I.
71	Ulmiphyllum densinerve n. sp...............................................	.......				.......	.......		.......	........
72	Ficopbyllum serratum Font..................................................			.......			.......	.......	.......	........
73	Sassafras Mudgii Lx..........................................................						.......					......
74	Platanus cissoidos Lx. (?)....................................................						.......		.......	........
75	Celastrophyllum pulchrum Ward n. sp......................................	.......		.......				.......		........
76	Sapindox)sis variabilis Font..................................................	.......			.......		.......	.......		........
77	Cissites salisburitefolius Lx..................................................			.......				.......	........	........
78	ingens Lx...........................................................				.......	.......	.......	........	........	........
79	Viburnites Evansanus Ward................................................			.......		.......	.......	.......	........	........		.____quot;
80	Male ament of a dicotyledon.................................................	.......		.......	.......	.......			X	.......
81	Carpolithus fasciculatus Font...............................................	.......	.......		.......	.......	.......	.......	X	.......
82	raontium-nigrorum Ward n. sp..................................	.......			.......		.......	.......	X	.......
83	barrensis Ward u. sp.............................................	.......	.......	.......		.......	.......	X	.......	........	.......
84	virginiensis Font...............................................	.......	.......	.......	.......	.......	.......	.......	.......	........	�. � �quot; �
85	fcenarius Ward n. sp............................................	X	.......	.......	.......	.......		.......	.......	........	�. *quot; �
86	FeistmanteUa oblonga Ward n. gen.n. ap......................................	.......	.......	.......	.......	.......	.......	.......	.......	........		___

) Jurassic.

19tli Geol., pt. 2-Face p. 712.

60 feet below the Dakotanbsp;sandstone.

Dakota group proper.

Lower Cretaceous.

Upper Cretaceous.

Jurassic.

Wealden.

Neocomian.

Urgonian.

Ap-

tian.

Gault.

Cenomanian.

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I nbsp;nbsp;nbsp;�W-nbsp;nbsp;nbsp;nbsp;�

PLATES.

PLATE LVII.

Cyoadean trunks from the Purbeok beds op the Isle op Portland, England, belonging to the U. S. ISTationalnbsp;Museum collection.

PLATE LVIII.

PLATE LIX.

From a pRotograpli of the specimen as mounted in the Royal Geological Museum at Dresden, furnished by Prof. Dr. Hans Bruno Geinitz.

K^ ^fh .'r-4r : . nbsp;nbsp;nbsp;--. �- � '� .'

r 4�

PLATE LX.

Group op fossil oycadban trunks from the Potomac formation OF Maryland, belonging to the Woman�s College OF Baltimore, collected by Mr. Arthur Bibbins.

In photographing the trunk represented by Fig. 10 it was accidentally inverted 722

PLATE LXI.

Group �f fossil oycadfan trunks fuou the Lower Cretaceous OF the Black Hills.

Scale, 1 meter.

GROUP OF CYCADEAN TRUNKS FROM THE LOWER CRETACEOUS OF THE BLACK HILLS.

PLATE LXII.

PLATE LXIII.

CYCADEOIDEA DACOTENSIS.

PLATE LXIV.

CyCADEOiDEA DACOTENSis (McBride) Ward emend... Side view of trunk No. 54 of tire Yale collection.nbsp;Scale, 20 cm.

CYCAOEOIDEA DACOTENSIS

......_.«Ë___________________________*_________________ _____________________» nbsp;nbsp;nbsp;_____quot;_ nbsp;nbsp;nbsp;_ '•V*________________________________.• __■__ -_ ■_*_ r ^1. •« !. nbsp;nbsp;nbsp;________» ^_______________«..V-X. *__ _ lt;■________‘ nbsp;nbsp;nbsp;__________■L»t__ *■__ ________________.....‘ __^ JL^ J

PLATE LXV.

View of the apex of trunk No. 54 of the Yale collection, showing helicoid , arrangement of scars in the terminal bud.

PLATE LXVI.

View of the fractured side of trunk No. 13 of the Yale collection, showing internal structure, terminal hud, etc.

CYCADEOIDEA DACOTENSIS.

PLATE LXVII.

Side view of trunk No. 6 of the U. S. National iluseum collection. Scale, 20 cm.

CYCADEOIDEA COLOSSALIS.

PLATE LXVIII.

A�iew of the hase of trunk No. 6 of the U. S. National Museum collection. Scale, 20 cm.

PLATE LXIX.

CENTIMETERS nbsp;nbsp;nbsp;;

CYCADEOIDEA COLOSSALIS.

PLATE LXX.

View of the apex of trunk No. 2 of the Yale collection. Scale, 20 cm.nbsp;nbsp;nbsp;nbsp;'

PLATE LXXI.

View of the base and interior of trunk No. 17 of the Yale collection. Scale, 20 cm.

PLATE LXXII.

PLATE LXXIII.

PLATE LXXIV.

PLATE LXXV.

PLATE LXXVI.

PLAICE T.XXVT.

PLATE LXXVII.

C VCADEOIDE A MIKNEKAHTENSIS 11. Sp .. -Trunk No. 14 of the Yale collection. Scale, 20 cm.

CENTIMETERS

CYCADEOIDEA M I N N EKA HTENS iS.

PLATE LXXVIII.

View of the external surface of the slab, No. 24 of the Yale collection. Scale, 20 cm.

PLATE I.XXIX.

Fift. 1. View of the exterior of one of tlie fragnienta of No. 83 of tlie Yale collection.

Fk;. 2. View of the fractured surface of franineut No. 86 of the Vale collection, showing also the terminal hud.

feixfe/* nbsp;nbsp;nbsp;^ 8 r

CgKTt^T�BS

CYCADEOIDEA MINNEKAHTENSIS,

PLAIT. LXXX.

Pig. 1. View of tlie perfect side of trunk No. 3 of the U. S. National Museum collection.

CENTIMETERS

CYCADEOIDEA PULCHERRIMA.

PLATE LXXXl.

View of tlie decayed side of trunk No. 3 of the IT. S. National Museum collection, intentionally inverted better to show the exposed internalnbsp;structure.

centimeters

CYCADEOIDEA PU LCH ERR I M A.

PLATE LXXXTT.

CENTIMETERS

CYCADEOIDEA PULCHERRIMA.

T^LATE LXXXIII.

CYCADEOIDEA CICATRICULA.

PLATE LXXXIV.

�LATE LXXXIV

CYCADEOIDEA CICATRICULA.

PLATE LXXXV.

PLA^PE LXXXVI.

r � i 3 T s 6 quot;f'XT'

I OEHTI meters

CYCADEOIDEA TURRITA,

PLATE LXXXVIL

PLATE LXXXVIII.

PLATE LXXXIX.

PTATE XC.

View of the fractured side of fragmeut No. lo of the Yale collection, showing internal structure.

CYCADEOIDEA TURRITA.

PLATE XCI.

Side view of the nearly perfect trunk, consisting of fragments Nos. 10 and 14 of the U. S. National Museum collection.

PLATE XCiT.

PLAICE XCII.

View of part of tlie surface of fragment .No. 9 of ttie 17. S. National Museum colleotiou, to show the leaf scars, enlarged nearly 2 diameters.

PLAICE XCAll.

View of the exposed iimer wall of the libro-cambiiim layer of frafiment Xo. 16 of the U. S. National Musenm collection, showing scars of thenbsp;vascular bundles.

PLATE XCIV.

CYCADEOIDEA McBRlDEi.

PLATE XCV.

View of the decayed upper end of trunk No. 23 of the Yale colleotion. Scale, 20 cm.

CYCADEOIDEA McBRIDEI.

PLATE XCVI.

PLATE XCVII.

View of the inner snrfiice of the armor as exposed in the fragment Ko. 57 of the Yale collection.

I -quot; 2 . 3 nbsp;nbsp;nbsp;4nbsp;nbsp;nbsp;nbsp;5nbsp;nbsp;nbsp;nbsp;6nbsp;nbsp;nbsp;nbsp;7nbsp;nbsp;nbsp;nbsp;8nbsp;nbsp;nbsp;nbsp;9 :

CENTIMETRS

CYCADEOIDEA McBRlDEI.

PLATE XCVIII.

Fig. 1. Trunk No. 29 of the Yale collection, supposed to represent a dwarf form of this species.

Pig. 2. Trunk No. 53 of the Yale collection, supposed toreiiresent a young form of this species.

PLATE XCIX.

PLATE C.

View of tlie exposed inuer wall of the woody zone and sections of the armor and axis of No. 110 of the Yale collection.

PLATE Cl.

PLAT?: CTI.

View of the under siirface of Trunk No. 11 of the Yale collection. Scale, 20 cm.

centimeters

CYCADEOIDEA MARSHIANA,

PLATE cm.

PLATE CIV.

C�MTmEY�f?S

CYCADEOIDEA MARSHIANA,

PLATE CV.

PLATE CVI.

PLATE evil.

PLATE GVIII.

PI.ATE CVIIT.

A'ie-vr of the outer surface of trunk Ko. 18 of the Yale collection. Scale, 20 cm.

PLATE CIX.

,5�#.S' :

Hi�i/'quot;�

^..C nbsp;nbsp;nbsp;lt;

PLATE CX.

CENTlMETEf?S

PLATE CXI.

PLATE CXIT.

C�NTtM�TE�?�

CYCADEOIDEA COLEI.

PLATE CXIII.

Pr.ATE GXTY.

Trunk No. 5 of the U. S. National Museum collection. � Fig. 1. Side Tiew, also showing the apex.

PLATE CXV.

CYCADEOIDEA PAYNEI.

PLATE CXVI.

PLATE CXYI.

CYCADEOIDEA WlELANDl.

PLATE CXVII.

Fig. 2. Inner face, showing armor and axis in longitudinal section. Scale, 20 cm.

PLATE CXVIII.

Fig. 1. Partially lateral view (if tnmk No. 64 of tbe Yale colli'etion. Fig. 2. View of tlie base of the same specimen.

PLATE CXIX.

Fig. 2. View of the external s^urface of fragment No. 50 of the Yale collection.

PLATE CXX.

Enlarged view of a polished section through the armor and woody zone of fragment No. 11 of the IT. S. National Museum collection, showingnbsp;internal structure, including one of the fruits cut longitudinally.

r, '1 nbsp;nbsp;nbsp;'gt;nbsp;nbsp;nbsp;nbsp;v'quot;nbsp;nbsp;nbsp;nbsp;'■■nbsp;nbsp;nbsp;nbsp;.gt;nbsp;nbsp;nbsp;nbsp;'*y JJ, ‘nbsp;nbsp;nbsp;nbsp;,-nbsp;nbsp;nbsp;nbsp;- .nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;:-. /l '‘j . •nbsp;nbsp;nbsp;nbsp;'-'j'nbsp;nbsp;nbsp;nbsp;' '• ,V t ..„

‘r- nbsp;nbsp;nbsp;*■* .nbsp;nbsp;nbsp;nbsp;' ii:'nbsp;nbsp;nbsp;nbsp;y “’*nbsp;nbsp;nbsp;nbsp;s Vi.nbsp;nbsp;nbsp;nbsp;' .S'i

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'-A . -'i/'V•'■'gt;, lt; nbsp;nbsp;nbsp;- :v ■ .nbsp;nbsp;nbsp;nbsp;-i^' ^ ■ ’'-ï

;' nbsp;nbsp;nbsp;-:**nbsp;nbsp;nbsp;nbsp;■_ ,•gt;•.'nbsp;nbsp;nbsp;nbsp;f^v,.nbsp;nbsp;nbsp;nbsp;,^gt;. ,nbsp;nbsp;nbsp;nbsp;-. ■ ■

t nbsp;nbsp;nbsp;«.-*nbsp;nbsp;nbsp;nbsp;X .'-'nbsp;nbsp;nbsp;nbsp;v; ,’■'. 'v.

h‘ W-A-V'-V-‘ '-•.‘■4 nbsp;nbsp;nbsp;0 \''nbsp;nbsp;nbsp;nbsp;' '■ .

BK iL.. nbsp;nbsp;nbsp;-nbsp;nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;‘nbsp;nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;'i.nbsp;nbsp;nbsp;nbsp;■/nbsp;nbsp;nbsp;nbsp;'

PLATE CXXI.

PLATE CXXII.

Fig. 1. Shortest side of Specimen No. 1, representing the lower portion. Fig. 2. Shortest side of specimen No. 2, representing the upper portion.nbsp;Scale, 20 cm.

PLATE CXXIIL

Fig. 1. View of the base of specimen No. 1, representing the true base of the trunk.

Fig. 2. View of the apex of specimen No. 2, showing the � crow's nest.� Scale, 20 cm.

848

PLATE CXXIV.

Fig. 1. View of the upper end of specimen No. 1, representing the lower portion.

Fig. 2. View of the lower end of specimen No. 2, representing the upper portion.

PLATE CXXV.

Specimens belonging to the State School of Mines of South Dakota. Restoration of the original trunk by superposing No. 2 upon No. 1 with annbsp;interval between to supply the lost parts, the dotted lines carried aroundnbsp;the margin of No. 2 to represent the amount of loss by erosion.

CYCADEOIDEA JENNEYANA.

PLATE CXXVI.

View of the polished surface of No. 1501 of the Woman�s College of Baltimore, showing leaf bases and fruits in cross section.

CYCADEOIDEA JENNEYANA.

PLATE CXXVII.

PLATE CXXVIII.

CYCADEOIDEA JENNEYANA.

PLATE CXXIX.

View of the trans verse fracture at top of No. 102 of the Yale collection. Scale, 10 cm.

CYCADEOIDEA JENNEYANA.

PLATE CXXX.

CYCADE.OIDEA JENNEYANA.

PLATE CXXXI.

View of No. 91 of the Yale collection from the side which best shows the terminal hud.

PLATE CXXXII.

CYCA.DEOIDEA JENNEYANA,

PLATE CXXXIII.

PLATE CXXXIV.

PLATE CXXXV.

I , nbsp;nbsp;nbsp;' V*%nbsp;nbsp;nbsp;nbsp;quot;.nbsp;nbsp;nbsp;nbsp;■* rnbsp;nbsp;nbsp;nbsp;.v'-.,-nbsp;nbsp;nbsp;nbsp;' 'nbsp;nbsp;nbsp;nbsp;-i.' 'i

PLATE CXXXVI.

CYCADEOIDEA INGENS.

PLATE CXXXVII.

View of tile trausverse fracture at top of specimen No. 103 of the Yale I collection, showing the axis with hollow center.

CENTIMETERS

CYCADEOIDEA INGENS,

PLATE CXXXVIII.

PLATE CXXXIX.

PLATE CXL.

PLATE CXL,

CYCADl�CilBEA INGBNS 11. Sp................................................. 632

View of a portion of tlio exterior and part of the exposed surface of the medulla No. 94 of the Yale'collection.

PLATE CXLI.

View of the transverse fracture of the upper side of No., 94 of the Yale collection.

PLATE CXLII.

PLATE CXLIIl.

888

PLATE CXLIV.

PLATE CXLV.

PLATE CXLVI.

PLATE CXLVII.

Side vie^v of Stillwell fragment No. 2 of tlie U. S. Natioual Museum collection.

CYCADEOIDEA STILLWELLl.

PLATE CXLVIII.

808

PLATE -CXLIX.

Trunk No. 56 of the Yale collection. Side view showing the expo.sed surface of the medulla and the corresponding inner wall of the woody zone in the detached fragment.

CYCADEOIDEA STILLWELLI.

PLATE CL.

Two views of opposite sides of trnnk No. 105 of the Yale collection. Sc.ale, 20 cm.

PLATE CEL

Fig. 1. View of the side on which the scars are most distinct. Fig. 2. View of the oblique base and broadest side.

PLATE CLII.

Cycadboidka Stillwblli n. sp... No. 119 of the Yule collection.nbsp;Fig. 1. Side view.

PLATE CLIII.

View of the best preserved side of the � Noble Cycad� of the U. S. National Museum collection.

908

PLATE OLIV.

G�MTlM�TEf?S

CYCADEOIOEA EXCELSA

PLATE CLV.

View of the base of the �Noble Cycad� of the U. S. National Museum collection.

PLAICE ELVI.

l^LATE CLVI.

Two views of difterent sides of trunk No. 84 of tlie Yale collection. Scale, 20 cm.

PLATE CLViL

PLATE CLVm.

, Fig. 2. Radial section showing walls with one row, or changing to two rows, of bordered pits, x 320.

Fig. 3. Tangential section showing wood cells and medullary rays, x 90. Fig. 4. Radial section showing wood cells and longitudinal section ofnbsp;medullary rays, x 90.

PLATE CLIX.

Fig. 1. Eadial section showing portion of medullary rays with minute bordered pits. X 320.

Fig. 4. Kadial section showing portion of very broad wood cell with two rows of nearly cirmilar bordered pits. X 320.

ARAUCARIOXYLON HOPPERTON/�.

PLATE CLX.

PLATP] CLXI.

platp: clxil

PLATE CLXIII.

PLATE CLXIV.

Fig. 4. Cone.

930

V,. .

PLATE CLXV.

CONIFEROUS PLANTS FROM THE LOWER CRETACEOUS OF THE BLACK HILLS.

PLATE CLXVI.

CONIFEROUS PLANTS FROM THE LOWER CRETACEOUS OF THE BLACK HILLS.

PLA^J�E CLXVII.

l-�iG. 1. Large stem natural size, from a photograph. Fig. 2. One of the scales enlarged 3 diameters.

PLATE CLXVIII.

Figs. 10 and 12. Enlargements of Figs. 9 and 11 (twice).

PLATE CLXIX.

TAXACEOUS AND DICOTYLEDONOUS PLANTS AND PLANTS OF UNCERTAIN SYSTEMATIC POSITION FROM THE LOWER CRETACEOUS OF THE BLACK HILLS.

PLATE CLXX.

PLATE CLXXI.

Fig. 4. Specimen from the Potomac formation, Aquia Creek series, at Fort Foote, Md., introduced for comparison.

PLATE CLXXII.

PLATP] CLXXIL

INDEX.

Kumbers in italics are those of pages on which illustrations (plates or figures) appear; numbers in black-facelt;l type are those of pages on which detailed descriptions ot species are given.

' nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;5	. nbsp;nbsp;nbsp;.nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;} 'o 'nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;*	�l5 * nbsp;nbsp;nbsp;*nbsp;nbsp;nbsp;nbsp;'nbsp;nbsp;nbsp;nbsp;� iquot;
	CENTIMETERS

* nbsp;nbsp;nbsp;�nbsp;nbsp;nbsp;nbsp;� �	10 '	15	-j-IT��
	CENTIMETERS

::J

K... nbsp;nbsp;nbsp;� �'

'1

' •■gt;■•''* nbsp;nbsp;nbsp;'^UiVw

-fx- -.yy- •

THE CRETACEO�S FORMATION OE THE BLACK HILLS AS INDICATED BY THE FOSSIL PLANTS

f:* -V

C: 1

CONTENTS.

ILLUSTRATIONS.

THE CRETACEOUS FORMATION OF THE BLACK HIT.I.S AS INDICATED BY THE FOSSIL PLANTS.

529

531

533

535

539

545

551

553

CRETACEOUS FORMATION OF THE BLACK HILLS.

555

.................................................................

in. THE BEACKIIAWK llEGION.

561

563

the BLACKHAWR region of black hills south DAKOTA

565

The history of Professor Jenney�s investigations will now be given. In June, 1894,1 received a letter from him dated June 10, from whichnbsp;I give the following extract:

Ii\Y(]m':EKliEGION

BLAGKIIIUS

CRETACEOUS FORMATION OP THE BLACK HILLS.

569

575

577

581

589

General section of the strata occurring in the Black Bills.

19 GEOL, PT 2�(2)-Face p. 593.

General section of the strata occurring in the Blade Hills.

19 GEOL, FT 2�(2)-Face p. 593.

597

Subkiiigdom SPERMATOPHYTA (Phanerogams).

Class BENNETTITALES Engler, 1897.

599

601

603

607

6�9

611

Pis. xci-c.

613

615

623

625

629

631

637

641

643

SUBKINGDOM SPERMATOPHYTA (Phanerogams).

LOWER CRETACEOUS FLORA.

3. LOWER CRETACEOUS FLORA OF THE BLACK HILLS, OTHER THAN CYCADEAN TRUNKS AND SILICIFIED WOOD.

NOTES ON LOWER CRETACEOUS PLANTS FROM THE HAY CREEK COAL FIELD, CROOK COUNTY, WYOMING.

647

649

DESCEIPTIOIS^S OF THE SPECIES. Subkingdom PTERIDOPHYTA (Ferns and fern allies).

651

Class FILICALES Engler.'

FERNS.

Genus WEICHSBLIA Stiehler.^

Weichselia reticulata (Stokes amp; Webb) Ward n. comb.

653

fi55

657

659

661

663

CRETAOEOUS FORMATION OP THE BLACK HILLS.

Asplenitjm: Dicksonianum Heer!

PI. CLXII, Figs. 6-8.