Sir : I have the honor to transmit for publication the very valuable report of Prof. Leo Lesquereux on the Fossil Flora of the Cretaceous Dakotanbsp;Group. This division, lying at the base of the Cretaceous series, forms anbsp;most important link in the physical history of the western portion of thenbsp;continent, containing as it does the first proofs of the introduction on thenbsp;earth of a vegetation allied to our fruit and forest trees. The formation alsonbsp;has a vast geographical extension, being exposed along the flanks of thenbsp;various mountain-ranges, from a point far north of our northern boundary,nbsp;and extending far south to Mexico. Nearly all the fossil forms, however,nbsp;vegetable or animal, that it has yielded up to this time, have been found onnbsp;the plains in the eastern portions of Kansas and Nebraska.

This elaborate memoir of Professor Lesquereux will be indispensable to every student of the geology of the West, and will reflect great credit onnbsp;the survey at home and abroad, and its immediate publication is earnestlynbsp;requested.,

THE FOSSIL FLORA

WESTERN TERRITORIES.

THE CRETACEOUS FLORA.

TABLE OF CONTENTS.

liue 2�, for Cryptogami�e read Crypfo-

lino 30, for Pbanerogami;� read Phauero-

line 3, for Phyllodadus read Pbyllooladiis.

line 14, for 2 read 1.

line 16, for 4 read 3.

line 12, for Diospiros read Diospyros.

line 32, for 30� read 35�.

line 22, for XXX, Pig. 12'gt;, read XXIX, Figs.

line 37, for PI. IV and V read PI. IV. lino 13, for 97 read 91.

EER ATA.

Page 55, line 11, for (p. 62, PI. XXIII, Figs. 2, 3,) read (I, p. 62, PI. XXIII, Figs. 8, 9, II.)

Dear Sir : I send you herewith my report on the fossil flora of the Cretaceous Dakota group.

Allow me to gratefully acknowledge the assistance received from you in the preparation of this memoir. The opportunity offered to me of exploringnbsp;the more interesting localities where the materials for this work have beennbsp;obtained was especially of great advantage. It enabled me to become acquainted with the geological distribution of the formation; to study the vegetable remains, and to compare their various forms in places where they werenbsp;more abundant; to recognize their local disposition, and thus to solve manynbsp;questions which, without this advantage, would have been left indefinite.

/; ' .• nbsp;nbsp;nbsp;wc;]/:.

ON THE FOSSIL PLANTS OF THE CRETACEOUS DAKOTA GROUP OF THE

UNITED STATES.

From the beginning of his explorations for the Geological Survey of the Western Territories, Dr. F. V. Hayden had remarked a formation of reddishnbsp;and yellow sandstone, with variously colored clays, seams of impure lignite, .nbsp;and remains of fossil plants, the whole group holding a position at the basenbsp;of the Cretaceous series of the Northwest. Already in 1853 he had obtainednbsp;a number of specimens of leaves of exogenous and dicotyledonous plants,nbsp;referable, according to his statements of that time, if not to species, at least tonbsp;genera still represented in our flora, or, as he said,^ closely resembling those ofnbsp;some of the higher types among our existing dicotyledonous forest-trees. Innbsp;1856 and 1857 the same geologist, then assisted by Professor Meek, foundnbsp;new specimens of these fossil plants in Nebraska; and later in their explorations of Kansas, undertaken in common for the purpose of studying the samenbsp;formation which some geologist had referred to the Trias,� they still discovered in that State a number of leaves of the same kind. They moreover ascertained that the Kansas formations are in exact correlation, in all their geological characters, with No. 1 of their Nebraska section, now bearing the namenbsp;of the Dakota Group. From a number of specimens these dicotyledonousnbsp;leaves of Kansas were recognized as identical with some which had beennbsp;formerly seen in abundance in strata of this Dakota group at the mouth ofnbsp;the Big Sioux River and at the Blackbird Hills, on the Missouri River, innbsp;Nebraska. Among these leaves especially were specimens of a trilobate leaf,nbsp;mentioned by Mr. Hawes, as found in the measures which he referred to the_nbsp;Trias of Kansas, and which had been exhibited at the Baltimore meeting ofnbsp;the Association for the Advancement of Science. In the discussion on thenbsp;age of the formation where these fossil plants had been recognized, the discoverers, Messrs. Meek and Hayden, remark, in the same paper, that these

2 Trias of Kansas, Uy F. Hawn, Trans. Saint Louis Academy of Science, vol. I, p. 171.

leaves certainly belong to a higher and more modern type of dicotyledonous trees than has yet been found even in Jurassic rocks, and that therefore thenbsp;formation could not beof Triassic age. And though they recognized it in immediate superposition to Upper Carboniferous or Permian rocks, they persisted innbsp;the former opinion of Doctor Hayden, that the red sandstones of the Dakotanbsp;group were of Cretaceous age. Some sketches of these plants had beennbsp;sent to Prof 0. Heer, of Switzerland, and in the meanwhile the whole collection of the leaves had been subjected to the examination of Doctor Newberry,nbsp;who wrote, �that they did include so many highly organized plants, thatnbsp;were there not among them several genera exclusively Cretaceous, he shouldnbsp;be disposed to refer them to a more recent era.�� After remarking that thesenbsp;plants did not represent any vegetable type older than Cretaceous ones, henbsp;says that the species, though probably all new, are closely allied to the Cretaceous species of the Old World. He refers them to the following genera:nbsp;Sphenopteris, Abietites, Acer, Fagus, Populus, Cornus, Liriodendron, Pyrus,nbsp;Alnus, Salix, Magnolia, Credneria, and Ettingshausenia; this last representednbsp;by that peculiar trilobate leaf mentioned above, which from better and morenbsp;numerous specimens has been since admitted as referable to the genusnbsp;Sassafras.

The discussion on the age of the Dakota group, which was then considered as Triassic by Messrs. Swallow and Hawn, and as Jurassic by Professor Marcou, was then complicated by the opinion of Professor Heer,nbsp;who, answering Doctor Hayden�s letter after the examination of the sketchesnbsp;sent to him, stated: That although one of the outlines resembles a Cretaceousnbsp;genus, {Credneria^ the nervation being obscure, and the others more likenbsp;Tertiary forms than anything known in the Cretaceous of the Old World, henbsp;was inclined to the opinion that they represent Tertiary species. From whatnbsp;is now known of the characters of the flora of the Dakota group, it is clearnbsp;that, judging from mere sketches, the celebrated professor of Switzerlandnbsp;could scarcely come to a different conclusion. But this has nothing to donbsp;with the discovery of the fossil plants of the Dakota group, and with thenbsp;history of the Cretaceous flora as we know it now. The above remarksnbsp;merely tend to prove that the first discovery of the vegetable Cretaceous remains of this western section is due to Dr. F. V. Hayden, who first by himself, and afterward in connection with Professor Meek, studied the formationsnbsp;where these remains have been discovered, first in Nebraska and afterward in

Kansas; marking exactly tlie limits and tlie characters of this group, now generally admitted as the lower member of the American Cretaceous formation.

Vegetable paleontology has been too often considered as of little importance in regard to the determination of the age of geological divisions. In this case at least we have an evident proof of its value as a guide ; for, indeed,nbsp;without the fossil leaves of Nebraska, the relation of the Dakota group eithernbsp;to the Trias, the Jurassic, or the Cretaceous, would be still uncertain andnbsp;subject to dispute; especially for the reason that the few animal remains recognized in the red sandstones of this group have been, as yet, too scant and ofnbsp;too little distinct characters to afford sufficient evidence on this point. Thisnbsp;proves the importance of the first collection of fossil plants of Prof. Hayden.nbsp;For now, as a result of his care in collecting them; in publishing geological factsnbsp;marking the exact relative position of the Dakota group to the Permian rocksnbsp;which underly it, and to the Cretaceous strata above it, and at the same timenbsp;forcing the examination and comparative study of these fossil plants, whichnbsp;most of the geologists of the time would have passed as unworthy of regard;nbsp;new researches have been induced; specimens have been obtained, more numerous, more perfect; and we have not only full geological evidence in regardnbsp;to the lithology and geological distribution of the strata, but the first pages ofnbsp;what may be called a new chapter of our geological history. To it have beennbsp;added the records furnished by the materials afterward brought up in abundance from various points.

The first contribution to these materials appears to have been furnished by Doctor Newberry. In reporting his opinion on the general character ofnbsp;the leaves submitted to his examination by Messrs. Meek and Playden, henbsp;adds this paragraph �} �1 may say in confirmation of the assertion that yournbsp;fossil plants are Cretaceous, that I found near the base of the yellow sandstone series in New Mexico, a very similar flora to that represented by yournbsp;specimens, one species at least being identical with yours, associated withnbsp;GryphcBa, Inoceramus^ and Ammonites of Lower Cretaceous species.� Andnbsp;in his report on Doctor Hayden�s fossil plants, he also remarks:� �That henbsp;subsequently went himself to the region where the vegetable remains hadnbsp;been obtained, and that he spent some years in the study of the geology ofnbsp;the interior of the Continent, exploring a large area occupied by Cretaceous

rocks in Kansas, Colorado, Arizona, New Mexico, and Utah. That during these explorations he obtained from the Cretaceous strata, at a great numbernbsp;of localities, angiosperm-leaves, consisting of some of the species obtainednbsp;by Doctor Hayden, with many others, all of which are described in the report of the San Juan expedition, not yet published.�

Unhappily for paleontological science, nothing is known as yet of these vegetable remains but what is said above, and they cannot be taken into consideration now as truly representing Cretaceous species. For the reason,nbsp;especially, that except from the Cretaceous strata of Nebraska, Kansas, andnbsp;Minnesota, we do not know as yet any fossil plants positively referable to anbsp;Cretaceous formation from the western territories named above, and traversednbsp;by Doctor Newberry in his survey. All our plants from these countries arenbsp;referable to the Tertiary, like those of Colorado, Wyoming, and of California.

In 1856, being on a tour of exploration on the southwestern limits of the State of Minnesota, I remarked, above the mouth of the Big Waraju, or Cotton-wood, which enters the Minnesota Eiver, near the present town of Newnbsp;Ulm, some exposures of a yellow-reddish sandstone bearing a few vegetable impressions, apparently representing leaves of willow. By reasonnbsp;of the generic identity of these leaves, I considered the rocks as of Tertiary age. I was the more disposed to admit this conclusion, as I foundnbsp;near by, in the bottom of the river, pieces of lignitic coal, evidently Tertiary,nbsp;which I supposed to have been taken out by the water, from beds underlyingnbsp;the sandstone, somewhere in the vicinity; for I was not then aware that innbsp;the Big Waraju, as in the Smoky Hill River and many affluents of the Missouri and the Minnesota, these pieces of lignite coal are carried by the currentnbsp;from the upper part of the rivers, where they cross the Tertiary formation,nbsp;hundreds of miles above.^ As I did not have then any instrument with me,nbsp;not even a hammer, and no means of transportation, I was unable to getnbsp;specimens of these fossil plants, and regretted many times thereafter the impossibility of comparing these Minnesota leaves with those of Doctor Hayden,nbsp;and especially with some referable to Balix, which I have since obtained innbsp;abundance from Nebraska and Kansas. In 1867, at the meeting of the National Academy at Northampton, Prof Jas. Hall, who had just returned from anbsp;geological exploration in Western Minnesota, exhibited, among a number of

' These lignites arc different from the shaly, friahlc, carbonaceous matter seen in the bluffs of the same river. They correspond by general aspect and chemical compound with the Tertiary lignite found, too,nbsp;in the bed of the Blue Earth Eiver above Saint Peter, in the Missouri, the Smoky Hill Eiver, amp;c.

other specimens, some fossil leaves taken from a red sandstone at about the same locality which I had formerly visited. From my impression in regard tonbsp;the geological distribution of the rocks which I had seen in place, and fromnbsp;the presence of two species of leaves recognizable among these specimens�nbsp;one Salix^ one Laurus, with apparently a Cornus, I then considered them asnbsp;pertaining to a Tertiary formation. By the kindness of Professor Hall I havenbsp;now these specimens for examination, and, comparing them with those of thenbsp;Dakota group of Nebraska, recognize them easily as from the same Cretaceousnbsp;formation. Some of the species are identical with those of the Blackbirdnbsp;Hills, and the compound of the stone is of exactly the same kind. It isnbsp;coarser, however, forming a rough-grained sandstone, which renders somewhat difficult the study of the specimens, on account of the obliteration of thenbsp;veins. Some of these leaves are described and figured in this paper.

In 1863 another geological exploration in the same field of research had also contributed new and interesting materials for the study of our Cretaceous flora. As has been stated already, the reference of the Nebraskanbsp;fossil leaves to a Cretaceous formation caused a difference of opinion betweennbsp;some American and European geologists concerning the true age of thenbsp;Dakota group. The details of the discussion on this subject are given atnbsp;length in Dr. Newberry�s Extinct Floras, {loc. cit.) Professors Marcou andnbsp;Capellini, two European geologists of celebrity, wishing to obtain for themselves full evidence on the conclusions of Doctor Hayden, undertook annbsp;exploration in Nebraska to visit the localities where the fossil plants hadnbsp;been discovered and to review the stratigraphical records on which thesenbsp;conclusions had been based. They obtained in their tour, especially in thenbsp;vicinity of Tekamah, as also from the Indian reservation in the Blackbirdnbsp;Hills, a number of specimens, which were delivered to Professor Heer fornbsp;examination. From these materials the Phyllites du Nebraska were prepared and published�a very interesting paper, 22 pages quarto, describingnbsp;seventeen species, all new ones, with four plates of illustrations. This memoirnbsp;gives us the first authentic and reliable record of our North American Cretaceous fossil plants, and is the more valuable on account of the high scientificnbsp;attainments of the author, of the accuracy of his descriptions of the leaves,nbsp;and of the figures by which they are exemplified.^ Of course the explora-

gt; Three leaves from the Dakota group are figured in Journal of Sciences and Arts, vol. xxvii No. 80 pp. 222 and 223,1869. They are, however, without description. The first has heen considered�a leaf ofnbsp;Liriodendron, the second a Credmria, the third a Sassafras.

tions of Messrs. Marcou and Capellini could but corroborate the facts already known from the reports of Dr. Hayden. They recognized the accuracy ofnbsp;the statements concerning the stratigraphical distribution of the members ofnbsp;the Dakota group, as also the conclusions advanced on its age. They evennbsp;acknowledge that after ascertaining that the American geologists were right,nbsp;they had been unable to pursue their explorations to as successful a result asnbsp;had been done by Dr. Hayden, having failed to discover the line of superposition of the Benton group with its animal fossils to the red-sandstonenbsp;bearing plants.

In the mean while the interest awakened by the discussions in regard to these plants and to their positive relation to the age of Nebraska sandstonesnbsp;had incited new researches, and the result was the discovery of a large numbernbsp;of better specimens, representing some species already known, and many newnbsp;ones, too. In the same year (1868) Prof. F. B. Mudge, of Manhattan College,nbsp;Kansas, collected, as State geologist, some splendid specimens of Cretaceousnbsp;fossil plants, which were sent to Prof F. B. Meek and to the Smithsoniannbsp;Institution. In 1867 Dr. John Leconte, while connected with the survey ofnbsp;the Union Pacific Railway, obtained also a number of fine specimens of fossilnbsp;leaves from the same red shales of the Dakota group, near Fort Harker;nbsp;and about the same time, Mr. Charles Sternberg, who was domiciled in thatnbsp;vicinity, discovered some localities rich in remains of fossil plants, and sentnbsp;many specimens of them to the Smithsonian Institution and to Dr. Newberry.nbsp;From the examination of specimens furnished to me by Dr. Hayden, Dr.nbsp;Leconte, and Professor Mudge, I prepared a paper entitled On Some Cretaceous Fossil Plants from Nebraska, the first paper published in America describing fossil plants of the Dakota group. This memoir^ gives an account ofnbsp;fifty-three species, eight of which were known already from the Fhyllites dunbsp;Nebraska, by Professor Heer, three referable with doubt to others alreadynbsp;published, and the balance, forty-one species, considered as new. Soon after,nbsp;a second paper, partly on the same subject, was published by Doctor Newberry and distributed in pamphlet form.� This very interesting memoir,

2 Thongli I do not attacli any importance -whatever to the right of priority of authorship for species of fossil plants, known from mere descriptions, I take this opportunity of fixing dates in order to sho-wnbsp;that my paper had precedence in distribution, if not of publication, to that of Dr. Newberry, and thatnbsp;therefore if a few identical species are described in both memoirs, under different names, I am in no waynbsp;accountable for it. My own report, as seen from its datum, was delivered to Dr. Hayden 19th March, 1868,nbsp;.and published in the Journal {loo, cit.) July, 1868. Dr. Newberry�s paper is marked by him as read the

The Late Extinct Floras of North America, describes, besides Tertiary plants, twenty-one species of fossil plants from the same Dakota group.

Later still, in Dr. F. V. Hayden�s annual report for 1871, eight new species are described by the writer, with mention of two already known, allnbsp;from specimens furnished by Dr. B. F. Mudge. And from my own explorations of 1872 over the Dakota group of Kansas I obtained a large number ofnbsp;fine specimens, serving to better illustrate some species already describednbsp;from insufficient materials, and adding to our list of Cretaceous species twelvenbsp;new ones for the American flora, three of which, howevei, were known fromnbsp;Europe and European publications.

All these species, already briefly described by myself either in the Journal of Sciences and Arts, or in the annual reports of Dr. Hayden, together with the new ones recognized from specimens collected in a tour of fieldnbsp;explorations in Kansas and Nebraska, (1873,) constitute the materials fromnbsp;which the present memoir is made. I must remark, also, that in order tonbsp;complete, as far as it was in my power, the history of the flora of the Dakotanbsp;group, I have added to the materials mentioned above, the description andnbsp;figures of five species which I had published, as an appendix to the Tertiarynbsp;plants of the Mississippi, in the Transactions of the American Philosophicalnbsp;Society, vol. xiii, and also of a few new species recognized in the specimensnbsp;kindly lent to me by Prof. Jas. Hall, which are described and figured withnbsp;his approval.^ I do this especially in order to have all together the materialsnbsp;pertaining to our Cretaceous flora. With Professor Newberry�s Report on thenbsp;Ancient Floras, which is to have also descriptions and figures of all his speciesnbsp;of Cretaceous plants, we have nearly the whole of what is known as yet ofnbsp;this interesting group of fossil plants. The only species which have beennbsp;described by Professor Heer and have not been published out of the Phyllitesnbsp;du Nebraska are: Salix nervillosa, Ficus �primordialis, Magnolia capellini, andnbsp;Cissites insignis. These, however, are remarked upon in the text of thisnbsp;memoir.

22d of April, 1867, and reprinted from tlie Lyceum of Natural History of New York, vol. ix, April, 1868. It was mentioned in tire Journal of Sciences and Arts November, 1868, and distributed at the same time innbsp;pamphlets, the copy sent me being received 7th November, 1868. As far as I am informed, no copies ofnbsp;this paper had been distributed at an earlier date.

1 By the kindness of the industrious and untiring investigator of the Cretaceous measures of Kansas Prof. B. F. Mudge, I have recently received, after the preparation of this paper, a now contribution ofnbsp;specimens, which has enabled mo to .add two new plates to the flora of the Dakota group, representing,nbsp;among others, ten species not described before.

10 � 2.�Surface distribution of the Dakota group.

In order to illustrate the geological relation of the species of fossil plants described in this memoir, it is convenient to make some remarks on the distribution of the group wherein they have been discovered. In doing this it willnbsp;be advisable to record facts already published by geologists who have formerlynbsp;explored this formation�by Dr. Hayden especially, by Professors Meek,nbsp;Mudge, Conrad, Marcou, Capellini, Hall, amp;c. These records and quotationsnbsp;are rendered necessary by the scattering of the materials referring to thisnbsp;group in scientific journals which are rarely accessible to paleontologists.

The eastern limits of the surface area of the Dakota group are marked in the Geological Keport of Iowa, by Prof C. H. White, who recognizes thenbsp;most easterly deposits of this formation, which he calls the Nislinahotanynbsp;sandstone, in the southeast part of Guthrie County, and as far south as thenbsp;southern part of Montgomery County. To the north it passes under thenbsp;Woodbury sandstone, overlaid by the Inoceramus, or chalky beds. The northwestern counties of Iowa have not been yet surveyed in detail, and owingnbsp;especially to the few exposures of the rocks underlying the drift, and thenbsp;prairies which cover this region, the exact limits of the group are not herenbsp;distinctly recognized. The direction, however, is, in Iowa, from near Councilnbsp;Bluffs north and somewhat east to the point where the Des Moines Rivernbsp;leaves Minnesota, and hence due north^ to the mouth of the Big Cottonwood River, near New Ulm, where the red sandstone is exposed in thenbsp;bank of the river. Prom this locality Professor Hall has recognized itnbsp;one hundred and thirty miles farther north. From Council Bluffs, or fromnbsp;above the mouth of the Platte, in Nebraska, the border of the belt passes innbsp;the same direction, south a little westward, across the western part of Cassnbsp;and Otoe Counties; thence to the middle of Gage County, near Beatrice;nbsp;then through Marshall County, entering Kansas in the eastern corner of Clay.nbsp;It descends farther south to the mouth of Solomon River, and reaches thenbsp;Arkansas River west of the line of the Atchison, Topeka and Santa F� Railroad, near the mouth of Cow Creek.

I can find no data marking the borders of the belt, nor even recording its appearance in the Indian Territory, between Kansas and Texas. Butnbsp;subsequent geological investigations cannot fail to recognize it in that country,nbsp;as its connection cannot be broken in that, as yet unexplored, region alone.nbsp;^Jdie records of the geological surveys of Texas and of Arkansas indicate it

in those States, in the same direction which it is following in Kansas, or nearly due south. In a note in the proceedings of the Academy of Sciencenbsp;of Saint Louis, Professor Shumard, after remarking,^ �that they had not before succeeded in finding dicotyledonous leaves in the Lower Cretaceous marlsnbsp;and sandstone of Texas, as had been done by Meek and Hayden in Nebraskanbsp;and Kansas, and that they supposed they would probably be found in thisnbsp;position,� adds: �I have now the pleasure to inform you that further explorations in Lamar County, near Red River, have resulted in the discovery,nbsp;by Dr. Gr. Gr. Shumard, of numerous impressions of leaves in alternations ofnbsp;yellowish sandstone and bluish shales which are believed to occupy a positionnbsp;below the marly clay, or Red River group of my section, and which we regard as being on a parallel with the lower beds of No. 1 of the Nebraskanbsp;section. The collection made by Dr. G. G. Shumard contains several speciesnbsp;of dicotyledonous leaves which appear to belong to the genera Salix^ Ilex,nbsp;Laurus, amp;c.�

At the time of the discovery of these fossil plants, I corresponded with Doctor Shumard, desiring that they should be sent to me for examination, andnbsp;I was promised communication of them. To my regret the promise was notnbsp;fulfilled, owing especially to modifications in the corps of the geological survey of Texas. There can be no doubt, however, from the description of thenbsp;position of the strata, of their compound, and also of the generic relationnbsp;of the leaves, that they are referable to species of the flora of the Dakotanbsp;group, or that this Cretaceous group is represented in the northern countiesnbsp;of Texas. The chalk-beds of the Cretaceous equivalent of the Benton groupnbsp;are predominant not only in Texas, but also in the southwestern corner ofnbsp;Arkansas, and have been recognized in the whole extent of Sevier, Pike,nbsp;and Hempstead Counties, amp;c. According to Dr. D. Dale Owen�s report onnbsp;the geological survey of Arkansas, this chalk limestone is seen in thesenbsp;counties, almost everywhere near the bottom of the creeks, under the loam.nbsp;On account of its lower station, of course the red sandstone of the Dakotanbsp;group was not observed, the beds of the river being nowhere deep enoughnbsp;to expose it to view. From North Texas, the Cretaceous formation passesnbsp;to the south, under wide prairies mostly of loam and Tertiary deposits.nbsp;It is not positively ascertained if it reaches the Gulf of Mexico, but it is

more than probable, as Hayden and Hall suppose, that it extends further south to the sea.

In tracing the eastern borders of the Dakota group, the length of its area from north to south is recognized from the northern limits of the Statenbsp;of Minnesota to North Texas, on about 20� of latitude. That this group extends farther north into British America maybe hypothetically admitted; andnbsp;as the fossil leaves received from Greenland by Professor Heer, and considered by this author as Upper Cretaceous, represent some genera and, perhaps,nbsp;some species too, identical with those of the Dakota group, it would seemnbsp;that this formation has been continuous from the Gulf of Mexico to thenbsp;Arctic lands, Greenland, Melville, amp;c., over 35� of latitude.

As far as it is known, in the States of Iowa, Kansas, and Nebraska, the average width of the belt occupied by the Dakota group from east to west,nbsp;varies from sixty to one hundred miles. It has been seen that the rednbsp;sandstone of this formation is exposed in the southeast part of Guthrienbsp;County, in Iowa, which is already ninety to one hundred miles east of Denbsp;Soto, on the Missouri River. In following up this river, the same formationnbsp;is still exposed to thirty miles above the mouth of the Big Sioux, where itnbsp;passes under the bed of the river.^ This, in a direct line, is at least onenbsp;hundred and thirty miles. In Nebraska State, the width of the belt is, according to Doctor Hayden, from sixty to eighty miles.*^ In Kansas I havenbsp;followed this formation along the Kansas Pacific Railroad, from the mouth ofnbsp;Solomon River, for seventy-five miles to the west. Professor Mudge has collected specimens of its fossil plants around Fort Lamed, and recognizednbsp;the sandstone of the Dakota group, up the Arkansas River, to the limitsnbsp;of the State. He says that the average breadth of this sandstone formationnbsp;in the northern half of the State is about forty miles, (northwest and southeast,) or about sixty miles in a diagonal line running due east and west. Butnbsp;when it reaches the bluffs of the Arkansas Valley the strike is westerly, andnbsp;instead of a westerly extension of sixty miles, it covers the whole countrynbsp;from thirty miles east of Pawnee Rock to the western line of the State, anbsp;distance of about two hundred miles.� It may be that it enlarges still farther south westward, for, according to Dr. Newberry�s statement, it reaches

' F. V. Ilayden�s remarks on the Cretaceous rooks of tlie West. American Journal Science and Arts, vol. xliii, p. 172.

New Mexico and the Rocky Mountains. I have not been able to find any trace of it in that country, however, and as all the specimens of fossil plantsnbsp;either found by myself south of Colorado or sent to me for examination fromnbsp;the Rocky Mountains or their eastern slopes, are species representative ofnbsp;the Tertiary formations, as remarked already, I am still uncertain if the Dakota group is really extended farther west than Kansas. The western stratanbsp;bearing plants which are now recognized as of Eocene age, were formerlynbsp;considered as Cretaceous, and the leaves found in great abundance in connection with the Tertiary formation, though of a different character, may havenbsp;been inadvertently referred to species of the Dakota group. However it maynbsp;be, this Cretaceous group has not been positively recognized by Dr. Haydennbsp;in his explorations to and along the Rocky Mountains, and from the naturenbsp;of its compounds, which, as it will be seen hereafter, induces me to considernbsp;it as a beach formation, I doubt whether it is of a much wider extent westward, as it has been reported, or whether it is to be found west of the bordersnbsp;of Kansas.

The section of the Cretaceous rock of the West, published in Dr, Hayden�s Report of the Gleological Survey of the Territories, 1870, p. 87,nbsp;gives the best possible illustration of the relation of the groups of the American Cretaceous from its base, in connection with the Permian, to its top, overnbsp;which the Eocene sandstone is superposed. It is here copied in full as anbsp;necessary exemplification of the details which are given in this chapter :

Gray, ferruginous, and yellowish sandstone, and arenaceous clays, containing JBelemnitclla hiilbosa., Nautilus delcayi,nbsp;Ammonites placenta. A. lobatus, Scaphites conradi, S. ni-colletti, Baculites grandis, Busycon hairdif Fusus Culbertson, F. newberryi, Aporrhais americana, Pseudo-buccinum,nbsp;nebrascensis, Mactra warrenana, Cardium subquadratum,nbsp;and a great number of other molluscous fossils, togethernbsp;with bones of Mosasaurus missouriensis, de.

Dark-gray and bluish plastic clays, containing, near the upper part. Nautilus delcayi, Ammonites placenta, Baculites ovatu8, _B. cqmpressus, Scaphites nodosus, Bentalium gracile,nbsp;Crassatella evansi, Oucullcea nebrascensis, Inoceramusnbsp;sagensis, I. nebrascensis, I. vanuxemi, bones of mosasaurus missouriensis, dc.

Middle zone nearly barren of fossils........................

Lower Fossiliferous zone, containing Ammonites complexus, Baculites ovatus, B. compressus, Jlelioceras mortoni, H. tor-turn, S. umbilicatum, M. cochleatum, Ptychoceras mortoni,nbsp;Fusus vinculum, Anisomyon borealis, Amauropsis paludi-niformis, Inoceramus subloevis, I. tenui-lineatus, bones ofnbsp;Mosasaurus missouriensis, dc.

Dark bed of very fine unctuous clay, containing much carbonaceous matter, with veins and seams of gypsum, masses of sulphuret iron, and numerous small scales,nbsp;fishes, local, filling depressions in the bed below.

Lead-gray calcareous marl,' weathering to a yellowish or whitish chalky appearance above; containing large scalesnbsp;and other remains of fishes, and numerous species ofnbsp;Ostrea congesta attached to fragments of Inoceramus.nbsp;Passing down into light yellowish and whitish limestone,nbsp;containing great numbers of Inoceramus problematicus,nbsp;I. pseudo-mytiloides, I. aviculoides, and Ostra congesta, fishnbsp;scales, amp;c.

Dark-gray laminated clays, sometimes alternating near the upper part with seams and layers of soft gray and light-colored limestone, Inoceramus problematicus, I. tenuiros-tratus, I. latuSyl.fragilis, Ostrea congesta, Yenila mortoni,nbsp;Pholadomya papyracea, Ammonites mullani, A. percari-natus, A. vespertinus, Scaphites warreni, S. lavvcBformis,

' S. ventricosus, S. vermiformis. Nautilus elegans, (?) dc.

Yellowish, reddish, and occasionally white sandstone, with, at places, alternations of various colored clays and bedsnbsp;and seams of impure lignite; also silicified wood andnbsp;great numbers of leaves of the higher types of dicotyledonous trees with casts of Pharella (?) daJeotensis, Axi-naea siouxensis, Cyprina arenaria.

It is now generally admitted that the upper strata of the limestone (mostly magnesian) underlying the Cretaceous, west of the Missouri River, belongs tonbsp;the l/ower Permian, though a large number of species of mollusks of the Carboniferous formations are still mixed in these strata, with predominant andnbsp;characteristic species of the Permian, in such a way that this limestone isnbsp;often called by. the name of Permo-carhoniferous. Until recently, I hadnbsp;never been able to see any trace of vegetable remains from this formation,nbsp;and thus to know what the fossil plants might indicate in relation to the evidence furnished by animal paleontology. In the explorations of Dr. Haydennbsp;of 1873, however. Dr. A. C. Peale discovered, in strata referred by himnbsp;either to the Carboniferous or the Permian, a number of well-preservednbsp;branches or stems of Calamites, whose identification proves for the formationnbsp;whence they are derived the same intermixture of characters referable to bothnbsp;the Permian and the Carboniferous. A large number of these specimens represent Calamites approximatus, Brgt., a species which as yet has been considered as belonging exclusively to the Carboniferous, and which in this case isnbsp;distinctly characterized by its very thick bark. The outer coating, which isnbsp;generally a compound of carbonaceous layers, is in these specimens petrifiednbsp;like the internal woody cylinder, but destroyed in some parts of the stems,nbsp;and in that way the different characters of both the internal cylinder and thenbsp;bark are exposed to view. The other specimens are well-preserved fragments of Calamites gigas, Brgt., which has been formerly considered bynbsp;Brongniart and Unger as an Upper Carboniferous species, but which now isnbsp;admitted as characteristic of the Lower Permian. After indicating its habitatnbsp;in the red sandstone of Alsatia, of Wettaravia, with specimens of Walchia innbsp;the Permian of Russia, amp;c., Schimper, in his Vegetable Paleontology, (1869,)nbsp;adds that this species has never been found in a productive Carboniferous formation, amp;c. These specimens were all obtained from the same localitynbsp;Eagle River, near Holy-Cross Mountain, Colorado, together with many fragments of undeterminable Stigmaria and one of an Asterophyllites. Thisnbsp;coincidence in the data furnished by animal and vegetable paleontology provesnbsp;that the end of the Paleozoic times in our American geology is marked, fromnbsp;the Mississippi River to the Rocky Mountains, by the Upper Carboniferous,nbsp;already modified by the first traces of Permian life.

The formation of the Dakota group, corresponding to the Upper Cretaceous of Europe, is now reeognized to be in immediate superposition to this

Ujjper Carboniferous.* On this subject Dr. Hayden remarks^ that �It is very difficult to find rocks of this Dakota group resting immediately upon thenbsp;beds below, from the fact that in almost all cases a grassy slope intervenesnbsp;that �it became a matter of much importance to find the junction of the twonbsp;great formations or to ascertain what beds come between.� For my exjfiora-tions of 1873 over part of the area of the same group, I was therefore directednbsp;by Dr. Hayden to carefully look to exposures where the strata positivelynbsp;referable to the Dakota group could be seen in immediate connection withnbsp;those of the underlying or overlying formations. Before exposing the resultnbsp;of my researches on this point, I will record here again the only case of immediate superposition discovered by Dr. Hayden, and published a long timenbsp;ago.� The observation was made near the old Otoe Village, about eight milesnbsp;above the mouth of the Platte River. � The section, in descending order, isnbsp;as follow:

� 1. Gray, compact, siliceous rock, passing down into a coarse conglomerate, an aggregation of water-worn pebbles cemented with angular grains of quartz; then a coarse-grained micaceous sandstone, 25 feet.

�2. Yellow and light-gray limestone of the coal measures, containing numerous fossils�Spirifer cmneratus, Athyris suhtilita, Fusulina cylindrica, with abundant fragments of coral and crinoid remains, 20 to 50 feet. A, quartznbsp;rock; B, conglomerate; C, coarse micaceous sandstone; D, Carboniferousnbsp;limestone.�

With the clay beds generally at the base of the Dakota group the series marked by letters resume, as will be seen, the essential lithological characternbsp;of the strata of the group.

Having recognized the connection, as marked above, along the Platte, I found in Gage County, near Beatrice, about eighty miles more southward,nbsp;along the banks of the Big Blue River, some exposures of the same kind,nbsp;where the strata of the limestone, with those of the Cretaceous sandstonenbsp;above, could be seen either in close or in immediate conjunction.* Thenbsp;variety in the nature of the lowest strata is at first seen at many places. Nearnbsp;the base of the group, beds of fine soft plastic clay, either white or, more

� The question of the relation of the Dakota group to European groups of the Cretaceous, as considered from analogy of vegetable remains, is discussed after the description of the species.

^Dr, Hayden had previously visited the same country, and recorded about the same observations.

generally, speckled or veined with red, are seen either alternating with or underlying banks of coarse, dark yellowish, easily disintegrating sandstone.nbsp;At one place, near a small branch of the Blue, such a bank of sandstone, 22nbsp;feet high, and perpendicular, has its sides hidden by thick strata of that softnbsp;clay, forming on both sides gentle slopes to the creek. The preponderancenbsp;of this clay, which either covers the underlying strata and hides them, easilynbsp;invaded as it is by vegetation, or which, removed by water erosions, is replacednbsp;by materials of transportation, renders more or less obscure or ill-defined thenbsp;line of superposition of the two formations. Grenerally, too, the upper magnesian limestone is shaly, easily disintegrated, and therefore prepared, likenbsp;the clay beds, for the formation of grassy slopes. All around Beatrice, evennbsp;in the town, as, for example, behind the mill, the shaly Permian limestonenbsp;may be seen exposed in banks overlaid by humus and trees, when at a shortnbsp;distance, and nearly at the same level, the sandstone of the Cretaceous isnbsp;exposed in a reverse condition, or with its base concealed by detritus ornbsp;by vegetation. In descending the river for five or six miles from the samenbsp;place, quarries are seen opened into an inferior member of the magnesiannbsp;limestone, which is there generally very hard and compact, without any fossilnbsp;remains, only mixed with concretions of clay and pyrites. This bed has anbsp;thickness of 4 to 10 feet, and passes above into irregular layers of shaly, fos-siliferous Permian limestone, ascending in some places to 30 feet high. Innbsp;exploring around, up the branches, the superposition of variegated clay or ofnbsp;sandstone upon the limestone is constantly recognized, though generally, asnbsp;said above, somewhat indistinct, sometimes a few feet only passing from viewnbsp;or being covered up between the two formations. I carefully observed anbsp;number of sections of the same kind in order to ascertain if, in cases of recognized and recorded immediate superposition of strata of the two formations,nbsp;the succession of these strata is always in the same order, and if any tracesnbsp;of materials representing an intermediate formation could be discovered anywhere. As far as the researches have been made until now, either by othernbsp;geologists or by myself, nothing has been seen under the Dakota group butnbsp;the Permian limestone, with which its lower members are always in contact.nbsp;A section of a continuous series of the Permian and Cretaceous rocks is exposed a few miles south of Beatrice, in a small branch, where a new quarrynbsp;has been opened for flag-stones, of poor quality. The stone is a magnesian,nbsp;fossiliferous, shaly limestone, worked down to about 6 feet, where it passes tonbsp;3 L

a more compact limestone of the same kind as that which is quarried in solid blocks six miles farther down the river. The section is as follows in ascending;

The stratum No. 2, 4 feet thick, is the line of transition or of superposition. In its lower j^art, and in contact with Permian limestone, it is Permian. In its npper part, the reddish sand is Cretaceous. The hillsnbsp;around are still, higher by 20 to 40 feet, and all, from base to top, at leastnbsp;from what is seen by exposures, are composed of the same hard red sandstone, which is more or less flaggy, and whose fragments ai'e heaped in moundsnbsp;by the farmers and used for building or for wells. In all this country, withnbsp;the exception of clay-beds, which are irregularly distributed in regard to thenbsp;horizon of the strata, the whole compound of the group is sandstone, rarelynbsp;mixed in horizontal streaks with small pebbles, occasionally yellow and crumbling, but most generally hard, ferruginous, either compact or cavernous, like allnbsp;the ferruginous sandstones. Its appearance is so little varied that it is everywhere easily recognized without the evidence of its leaves. No formationnbsp;could show a more striking contrast than it does with that of the underlyingnbsp;limestones of the Permian. In ascending upward through the higher stratanbsp;of the Dakota group, or in following the exposures of this formation along thenbsp;rivers to the west, the same uniformity is constantly remarked to the highestnbsp;point, where the upper beds of sandstone pass under the second or uppernbsp;group of the Cretaceous. For example, in Kansas, from the mouth of Salinanbsp;River to Fort Darker, I have all the time traveled along the banks of this rednbsp;sandstone. It is sometimes interstratified with beds of soft clay. Carbonaceousnbsp;matter, or streaks of coarse materials forming bands of conglomerate sandstone,nbsp;but the areas occupied by them are not of wide extent. They appear herenbsp;and there without apparent continuity, and are irregularly distributed in thenbsp;whole thickness. When near the surface, the clay-beds have been generallynbsp;decomposed and mostly destroyed under atmospheric action, forming hollowsnbsp;or depressions, which in some localities mold the surface of the prairies intonbsp;groups of small domes or hillocks, like a miniature of what is seen in such anbsp;grand scale in the Tertiary clay formations of the Mauvaises Terres. The

deepest hollows are, however, scarcely 20 feet lower than the tops of the hillocks. Generally these changes of consistence of the strata are marked bynbsp;mere undulating prairies. A few cases of the inter stratifications of materialsnbsp;apparently ditfering in composition, are mentioned in remarking upon thenbsp;localities where they have been observed. The general character of the groupnbsp;may therefore be described as a succession of more or less coarse, sandynbsp;materials, regularly stratified, more or less impregnated with oxide of iron,nbsp;and, according to the prevalence of this mineral, either hard, compact, darknbsp;red, or yellowish, composed of sandy grains more loosely cemented and morenbsp;easily disintegrated ; the whole mass being interlaid by deposits of fine potter�s clay, yellowish, white, or red spotted, or black, rarely mixed with carbonaceous matter, distributed more generally near the base and the top of thenbsp;formations in areas of small extent.

The thickness of the Dakota group has not been as yet, and could scarcely he, exactly ascertained without borings made at many distant localities.nbsp;In the land of prairies where it prevails, the rivers are bordered by banks whosenbsp;elevations are from 30 to 60 feet, rarely reaching an altitude of more than 100nbsp;feet. In South Nebraska, around Beatrice, the section made by Dr. Haydennbsp;in his report, (1867, p. 27,) estimates the whole thickness of the group atnbsp;150 feet. It is the same measure which I marked in ascending from thenbsp;quarries on the Big Blue, counting it from the upper exposure of the Permian,nbsp;the shaly fossiliferous limestone, to the top of the highest hill above, composednbsp;of red shale in its whole thickness. But at a short distance to the south therenbsp;is still a succession of hills of the same formation which are at least 40 feetnbsp;higher. On the banks of the Missouri River, near the Indian reservation, thenbsp;bluffs of sandstone, as exposed above the alluvial deposits which cover theirnbsp;base, measure from 70 to 100 feet, generally perpendicular. I have seen,nbsp;probably about at the same localities where Dr. Hayden made the sectionnbsp;recorded in the report of 1867,* the sandstone exposed 120 feet from its base,nbsp;where it is apparently covered by 20 to 25 feet of detritus and alluvial matter,nbsp;and from the top, in ascending along a quarry road, I dug here and there fromnbsp;the surface loose pieces of the same sandstone, to 70 feet higher. Accordingnbsp;to Meek and Hayden, the dip of the strata of the whole series, which restsnbsp;conformably upon the Permian limestone, is to the northwest.� This dip is of

slight degree, indeed; but considering only the slope of the area covered by the formation in its width from east to west, there is in sixty miles only, as fromnbsp;Papillion Station to Schuyler, on the Union Pacific Railroad, a difference ofnbsp;375 feet of altitude. These figures, representing the thickness of the strata,nbsp;should be still increased by the amount of the dip. It appears, therefore, thatnbsp;the estimate of Professor Swallow of a thickness of about 400 feet for thisnbsp;formation is not overrated. I take this estimate from the report on the geological survey of Kansas,^ adding to it the three upper members of the fourthnbsp;section, marked Triassic, overlaying the buff magnesian limestone. Thenbsp;group is described as a compound of brown, ferruginous yellow and buffnbsp;sandstones, which, says the author, �are generally classed as Cretaceous, thoughnbsp;I saw no proof of its age.� The same thickness is already marked in Hayden�s Report on the Exploration of the Yellowstone and the Missouri Rivers,nbsp;l859-�60, published in 1869, where, in the section of the Cretaceous rocks ofnbsp;Nebraska, the Dakota group is estimated 400 feet thick, as in the section recorded in the beginning of this chapter. The thickest continuous series ofnbsp;the sandstones which have been measured and recognized as bearing leaves,nbsp;from the base to the highest point, is that mentioned by Prof. B. F. Mudge,nbsp;of Manhattan College, in the Kansas Agricultural Report of 1872, where, innbsp;Clay County, near Roverdale, Kansas, the fossil leaves were found at the bottom of a well 35 feet deep, as low as the bed of the Republican River, and onnbsp;the top of the adjoining hills, 200 feet high. The thickness of the strata isnbsp;related, of course, to the depth of the local erosions into the formation whichnbsp;they cover. As indicated from the homogeneity of the compounds, however,nbsp;it is apparently generally the same, only increasing somewhat toward the west,nbsp;Having positively recognized the point of superposition of the Dakotanbsp;group to the Permian limestone, and the permanence in the characters of thenbsp;strata which come in juxtaposition at the base of this group, it is importantnbsp;also, to look for the same kind of evidence in the succession and modificationnbsp;of its upper strata in the line of union with a higher member of the Cretaceous. For this we have still to receive our more precise informations fromnbsp;the records of the explorations of Dr. Hayden, who has so carefully studied and so admirably described the Dakota Group, in fixing its limits, andnbsp;marking its characters, that he has scarcely left anything to discover to thosenbsp;who have followed him in the same field of researches. He has seen at two

different localities the upper limits of the lower group, and its connection with No. 2 of the Cretaceous. First, near the mouth of Iowa Creek, on thenbsp;eastern side of the Missouri River, where the river cuts the bluffs, and wherenbsp;the rocks are seen all in their order.^

3. Niobrara group, layers of white,and yellow chalky lime, passing down into gray marly rock.

2. nbsp;nbsp;nbsp;Black plastic clay with hard layers, containing Inocermnus, a speciesnbsp;of Ostrea, like O. congesta, remains of fishes, crystals of sulphuret of iron,nbsp;selenite, amp;c.

1. nbsp;nbsp;nbsp;Dakota group, sulphuret of iron, fragments of wood, impressions ofnbsp;leaves, willow, laurel, amp;c.

The second case of superposition of both formations is marked by Dr. Hayden six miles above the mouth of the Big Sioux River, where the stratanbsp;are reported in the same order as in the former :

3. nbsp;nbsp;nbsp;Shaly limestone, gradually passing into the bed below, with an abundance of Inoceramus prohlematicus and of fish-remains.

1. nbsp;nbsp;nbsp;a, Yellow friable sand; b, earthy lignite, six inches ; c, variegatednbsp;sandstone and clays, with dicotyledonous leaves.

In following the bluffs of the Missouri River, about eight miles east of the Winnebago village of the Indian reservation of the Blackbird Hills, I obtained another well-exposed section of the Upper Dakota group and of thenbsp;Cretaceous formations above it, as follows :

3. nbsp;nbsp;nbsp;Impure limestone, formed of an agglomeration of large shells, Inoceramus, Ostrea, amp;c., with sandy yellowish clay; worked for lime from the surface to the bed below, eight feet.

1. Yellow sandstone, easily disaggregated, with streaks of hard red sandstone or ferruginous clay, passing down to compact red sandstone, 50 feet.

At this place, about two miles north of Warner�s Quarry, I did not find any leaves in the formation which from its top represents the Dakota group.nbsp;But in following the bluffs down to that new-opened quarry, I found annbsp;abundance of remains of fossil plants to the highest point, or in the yellownbsp;friable sandstone immediately topped by the strata of No. 2, the Bentonnbsp;' Geological Survey of the Territories, 18C7, p. 48.

grouj) of the Cretaceous. At this quarry, which has been recently opened for the purpose of obtaining good building-materials, which are hauled to thenbsp;Winnebago village, I saw for the first time that intercalled quartzite banknbsp;which is mentioned in the same report of Dr. Hayden, page 46. He describes it � as a very compact quartzite, the hardest and most durable rock innbsp;the State, found all along the hills opposite Sioux City.� At this quarry thenbsp;stone is of a dark grayish color, generally in two banks, one 4 feet thick, thenbsp;other, above, 2 to 3 feet, with an interlaying of a few inches of hard clay.nbsp;The lower is the more compact, hard as flint, giving fire by percussion, andnbsp;therefore difficult to break. It contains fragments of leaves, some entire andnbsp;well preserved, with distinct nervation; all, at least all those which I havenbsp;seen, extended flat in the plane of stratification. This bank is underlaid immediately and without transitional modification of the materials in contactnbsp;by soft-grained sandstone, easily cut with the knife, marked at different localities by rough Indian sculptures of animals, amp;c., which, as remarked by Dr.nbsp;Hayden, {he. cit.,) appear doubtless portions of the hieroglyphical history ofnbsp;the Indian. This lower sandstone is more or less exposed in proportion tonbsp;the amount of detritus and alluvial covering its base. The best exposition otnbsp;it is from 20 to 25 feet. Above the quartzite the sandstone is more ferruginous, darker, and hard. It has generally rare impressions of leaves ; but justnbsp;above Warner Quarry, under the thin coating of humus which covers the topnbsp;of the hill with vegetation, the remains of plants are in greater quantity thannbsp;I had seen them anywhere else in the vicinity. This place is little morenbsp;than one mile from the locality where No. 2 is exposed at the same level,nbsp;and therefore it appears that the fossil leaves do not become less abundant innbsp;the upper part of the Dakota group. The whole section of the Warnernbsp;Quarry is 60 feet. Quite near Iowa City, the upper strata of the same groupnbsp;are intermixed with beds of impure lignite, a matter without any value as combustible, and the sandstone underlying them is blackened by an immensenbsp;mass of roots and rootlets of fluvial plants. This appearance is most likenbsp;that of the clay strata underlying beds of Tertiary lignite, or of the true coal ofnbsp;the Carboniferous epoch. In this last case the remains in the under day-beds are leaves of Stigmaria; in those of the Tertiary coal-beds, they arenbsp;evidently roots and rootlets of water-plants, recognized especially by thenbsp;tubercles and rhyzomas of the Equisetum. At Sioux City the roots in thenbsp;clay-beds are mostly undeterminable. They are mixed with fragments of

brandies and leaves of conifers heaped in a confused mass, and deformed by a too advanced stage of decomposition. These shales are immediately belownbsp;the under layers of the upper group, No. 2, v/hich they resemble bynbsp;their color and the presence of scales of fishes. However, they still havenbsp;the essential characters of the Dakota group, viz, dicotyledonous leaves.nbsp;Among others, I found there an entire leaf of the same species of Laurus,nbsp;which is common from Minnesota to Kansas, in the whole thickness of thenbsp;formation, and the only species seen in the bed of quartzite in the Blackbirdnbsp;Hills. From this we may conclude that the whole group bears, with scarcelynbsp;any change in the nature and compound of its strata, the same essential character, or its peculiar vegetable remains, from the lowest strata to the line ofnbsp;conjunction with the Fort Benton group above it.

For a time, as remarked before, the clay-beds, which had been observed mostly at the base of the Dakota group, were considered, without paleontological evidence however, as representing either the Jurassic or the Triassicnbsp;formation. This supposition was derived from the idea of a sequence of thenbsp;geological formations, as they are generally admitted, and, of course, it seemednbsp;at first incredible that formations like the Triassic and the Jurassic, whichnbsp;have immense development in Europe, should be without any trace of representatives over the coal-measures of the West. The subject has been satisfactorily discussed, and little evidence can be added to what has been published already. There was still, however, some uncertainty in regard to thenbsp;geological reference of the clay-beds at the base of the Dakota group, which,nbsp;overlying the Permian, are locally of a tolerable thickness, and where, as yet,nbsp;no fossil remains, either animal or vegetable, had been found. This lowestnbsp;member is marked by Professor Swallow as especially predominant in thenbsp;vicinity of Smoky Hill River, Cottonwood, and Fancy Creek, where it is composed of brown, drab, and reddish marls and shale 32 feet thick. I had. annbsp;opportunity to see these clay-beds exposed at many places along the Smokynbsp;Hill River, and unexpectedly found in them a peculiar kind of remains whichnbsp;give positive evidence of their Cretaceous age. The essential exposure wherenbsp;the discovery was made is at the bottom of a small branch of the river, aboutnbsp;fifteen miles southeast of Fort Harker, where a layer of coal, or rather of carbonaceous matter, 1 to 2 inches thick, crops out, interlaid into a bank of soft, black,nbsp;laminated shale. The traces of coal in the creek have stimulated a searchingnbsp;for some thick bed of the same matter in that locality, and one shaft has been

sunk near the creek to 15 feet through the bank of soft black shale there overlaid by white plastic clay. I believe that the bottom of the shaft is notnbsp;far from the Permian limestone, if it does not reach it; but this could not benbsp;ascertained, the bed of the creek being in a deep depression, as low nearly asnbsp;the bed of Smoky Hill River. The materials taken out of the shaft had beennbsp;decomposed by atmospheric action; the small fragments of shale did not shownbsp;trace of organic remains ; but having dug out from the bed of the black shalenbsp;in the creek some large pieces, in order to get specimens of the coal, I wasnbsp;surprised to see them, in their contact with the carbonaceous layer, coverednbsp;by a prodigious quantity of fragments of a plant which has been recentlynbsp;discovered in the Neocomian of Switzerland, and has been seen as yet innbsp;this Cretaceous formation only. These remains have been described undernbsp;the generic name of Gyrophyllites. Professor Heer, in his Urvoelt dernbsp;8chweitz, page 190, has figured and briefly described four different forms,nbsp;which he considers as species of vegetable. These remains are in whorls ofnbsp;six to ten linear, slightly oblanceolate divisions, attached to a common center,nbsp;like the spokes of a wheel, and, where I found them, superposed and heapednbsp;in immense numbers one upon another in such a way that the impressions otnbsp;the whorls and their divisions were perfectly distinct, but the stems andnbsp;branches could not be seen. The relation of form of these small plants isnbsp;with the Annularia of the coal measures, which are also often seen in accumulated whorls without distinct impressions of their stems or branches.nbsp;In the form observed in Kansas, the divisions are short, measuring scarcelynbsp;more than one-fourth of an inch, gradually widening from the base to the angular point. Their impressions into the shale are deep and angular or withnbsp;a deep medial line, as if they had been made by three-faced or prismatic ab-ruptly-jjointed crystals of selenite. Indeed, most of them were exactly fillednbsp;like molds by those crystals, and it is the reason why, after a protracted examination, I was left uncertain of the true nature of these remarkable impressions. The whole mass was, moreover, so fragile that it was difficult tonbsp;separate anj portion of it in the horizontal plane of their marks, and I couldnbsp;not carry away and preserve any specimens for drawing and descriptions. Inbsp;have, however, seen at Fort Harker, in a small cabinet of* fossils from thenbsp;vicinity, one piece of red sandston� found at the same locality with dicotyledonous leaves, which bears whorls of the impressions of those Gyrophyllites,nbsp;with appai'cntly traces of branches or stems. Unhappily, I could not obtainnbsp;the specimen on account of the absence of the owner.

Professor Heer, considering these organisms, remarks that their systematic relation is very uncertain. They are, by the disposition ofnbsp;their divisions, distantly comparable to the Characem, but that is all. Asnbsp;they have been found in Switzerland, only in connection with deep animalnbsp;marine remains and fucoids, they should have lived in the seas, if they didnbsp;represent vegetable, while from their association in this country with dicotyledonous leaves the contrary assertion would be authorized. They may be,nbsp;after all, the marks of a peculiar kind of crystallization, and it is to be hopednbsp;that somebody may procure from our Cretaceous measures specimens in suchnbsp;a state of preservation that the true relation and nature of these fossils maynbsp;be ascertained. In any case their presence in the lower beds of clay of thenbsp;Dakota group should be recorded as an indication of their geological relationnbsp;with the European Cretaceous. And of course these fossils, though withoutnbsp;any relation recognized as yet, are positive evidence of the continuity of thenbsp;series of the Dakota group from the point of contact of the clays with thenbsp;Permian beds of limestone. No trace of an intermediate formation can benbsp;admitted between them. This opinion has been from the first admitted bynbsp;Dr. Hayden, and the further the explorations are pursued the more generally accepted it becomes. Professor Mudge, in the Agricultural Report ofnbsp;Kansas, already quoted, says �Observations made the past year (1871) confirm my statement read before a former meeting of the association, viz, thatnbsp;there is in Kansas no geological representation of the formations found innbsp;other countries between the upper Carboniferous or Permian, and the Cretaceous. Careful research has been made for fossils of Jurassic and Triassicnbsp;periods along the western borders of the Permian, and none have been found,nbsp;while dicotyledonous leaves and Cretaceous fossils have been procured latelynbsp;nearer the line of the Permian than during our first collection.� In a letternbsp;of October, 1873, the same geologist writes that: �Since writing the abovenbsp;article I have become settled in the idea that the Dakota group rests directlynbsp;on the Permian, as I have found leaves of the Cretaceous and shells of thenbsp;Permian within three miles of each other, at about the same horizon andnbsp;without traces of any intermediate formation.�

Dr. F. V. Hayden, in a paper in the American Journal Sciences and Arts, vol. xliii, March, 1867, p. 178, remarks: �Both Mr. Marcou and Pro-

fessor Capellini agree in regarding this sandstone in which the dicotyledonous leaves are found as a fresh-water formation. I would simply say that I have always regarded it as marine, and I am sure this has beennbsp;the opinion of my friend Mr. Meek. At any rate, we have found nringlednbsp;with the leaves at Sioux City quite well preserved casts of Pharella dnko-tensis, Axinea siouxensis, and Cyprina arenacea, shells peculiar to marine deposits.� Since that time a number of species of marine mollusks have beennbsp;found in the strata of this group, and Dr. Mudge, in his paper quoted abovenbsp;from Transactions Kansas Agricultural Eeport, p. 396, gives a list of speciesnbsp;determined by Prof B. F. Meek, all referable to marine mollusks: Crassatel-lina oblonga. Area parallda, Yoldia microdonta, Cardium kansasensis, C. sali-nens,Cyrena {Corhicula) nucalis,C. suhtrigonalis, Tellinasubscitula, T. mactroides,nbsp;Leptosolen conradi, Turritella kansasensis, Turbo mudgeanus. Professor Mudgenbsp;remarks on these shells that: � They are in the same strata and in the vicinitynbsp;of several deposits with the dicotyledonous leaves, and together with thenbsp;plants, identify this portion of the sandstone as belonging to the Dakota groupnbsp;of the Cretaceous, as described by Messrs. Meek and Hayden, in their firstnbsp;report.��

The opinion that this group of the Cretaceous may be a fresh-water formation is, moreover, contradicted by its extent and by the homogeneousness of its compounds. It has been seen that at some places it covers an area ofnbsp;more than sixty miles in width, and that its length along the borders of thenbsp;Carboniferous or Permian measures is recognized as continuous from Texasnbsp;to the northern limits of Minnesota, thus passing through fourteen degrees ofnbsp;latitude, even probably across the English portion of Forth America to Greenland. It is not possible to suppose a fresh-water formation of such extent,nbsp;especially when we consider, as stated above, the homogeneity of the materialsnbsp;composing it. For, indeed, with the exception of thin local strata of carbonaceous shale and soft clay, especially observed near its base, the compound is essentially the same in the whole thickness and in the whole extent, varyingnbsp;only in degree of hardness, compactness, and red coloring, resulting from thenbsp;different proportion of oxid of iron with which it is impregnated. This formation, by the character of its ferruginous arenaceous shale, even by its color,nbsp;and also by the special character of its flora, has the greatest analogy with thenbsp;red sandstones so widely formed at the end of the Devonian epoch, betweennbsp;the Chemung and the Carboniferous, cither as the Catskill group, or as the

Subcarboniferous (Umbral, amp;c., of Roger,) underlying the anthracite basin of Pennsylvania, and extending southward to North Carolina, and also withnbsp;the New Red Sandstones of the Lower Permian. Of course, in this comparisonnbsp;the difference of the epochs has to be taken into account. But in all thesenbsp;formations we remark a peculiar compound without relation to past andnbsp;sequent formations; a great uniformity of these compounds which are muchnbsp;alike at the different epochs; a nearly total absence of animal remains, and anbsp;flora, exclusive in its characters and without marked relation to the floras ofnbsp;corresponding times. The origin of these groups of red sandstone is the same,nbsp;to my belief, at least. They are beach formations, like those in progress at thenbsp;present time along the shore of the North Sea, in Holland and Belgium, wherenbsp;the widely extended muddy shores are formed of a soft substance of the samenbsp;red color. As I have had opportunity to observe it, it is a mixture of smallnbsp;grains of sand, brought from the sea, with the mud deposits, carried by rivers ofnbsp;long course, after traversing flat countries. By slow deposition, it constitutes lownbsp;shores, successively washed by the tides, which, of course, recede or advancenbsp;farther in proportion to the slow upheaval or to the depression of the land.nbsp;Marine animals, the shells especially, are very rare in a formation of this kind.nbsp;It has only a few species mostly of small size; also the prints of the tracks ofnbsp;Saurian, of birds, amp;c., the ripple-marks, the cracks or the preforation causednbsp;by atmospheric influences, dryness, heavy rain or hail. But it is shunned bynbsp;every kind of land animals, and it has, therefore, no other remains imbeddednbsp;into its compound but Saurians, and rarely fishes.^ Its flora is for the samenbsp;reason of a peculiar character. It has no remains of marine plants, for thesenbsp;do not grow on the mud or upon soft ground ; the vegetation of high dry land,nbsp;and also that of the bogs or of the peat, are excluded from it; the first onnbsp;account of the humidity and softness of the ground, the other from its constant alternance from a dry to a submerged surface.

The character of the leaves found in the Dakota group, and their analogy with species of our time, seem at first to refer them to a dry-land flora; itnbsp;is, however, not positively the case. The most abundant representative of thisnbsp;Ci�etaceous flora, the Sassafras, is remarkably similar to the present Sassafrasnbsp;officinale, which inhabits every kind of ground and station, from the dry hillsnbsp;of Ohio to the low swamps of Arkansas. The numerous leaves of Laurus,nbsp;too, are comparable to those of Laurus caroliniam, a shore plant, as are also

1 111 Hollaud the ditobes across tho flats, wbcro water is permanent, are mostly inbabited by cels ill prodigious quantity.

the Magnolias, Platanus, Fopulus, Salix, and Menispermites, the essential types of the vegetation of the Dakota group being, therefore, those of lownbsp;islands or of low shores, rather than of hills and dry land.

Professor Capellini remarks, in his introduction to the pamphlet on the Pliyllites du Nebraska; � Although the Tekamah molasse is distinctly stratified, the vegetable impressions are not arranged in the plane of stratification;nbsp;a proof that the water wherein were deposited the materials which entombednbsp;the leaves, and which were brought by alluvion, was not quiet enough. Thenbsp;deposit was not made quietly enough to allow the leaves to be flattened asnbsp;well as those which are found in the deposits of Oeningen and of Senigallia.�nbsp;The fact stated by the European professor is not generally observed. Thenbsp;leaves, indeed, are found sometirnes rolled or crumbled as may have beennbsp;dry leaves when falling upon a muddy surface where they may have beennbsp;imbedded in that condition, and often, too, penetrating the mud edgewise,nbsp;either vertically or in various degrees of inclination to the plane of the mudnbsp;deposits; at some places they have been also probably rolled by the waves.nbsp;But these deviations of the horizontal plane are far from frequent. In mostnbsp;cases the leaves are flattened upon the shales, often found covering eachnbsp;side of a piece of shale of moderate thickness, and also when in abundancenbsp;they are generally superposed and flattened upon another. This deviation of the horizontal plane is nowhere more marked for the fossil plants ofnbsp;the Dakota group than for those of our Carboniferous or of our Tertiarynbsp;formation, and it appears rather ascribable to wind or to tidal action than tonbsp;any current or alluvial movement. These remarks already tend to indicatenbsp;that the Cretaceous fossil leaves have been derived from trees or groups ofnbsp;trees growing in the vicinity of the muddy bottoms where they have beennbsp;buried and fossilized. Other facts confirm this assertion.

The leaves are regularly disseminated in the shale of this formation, and thus found here and there over wide areas. They are often very abundantnbsp;at one locality, occupying a surface of small extent, and then they disappearnbsp;entirely from the same horizon and are not seen anywhere around for miles.nbsp;The locality near Salina, from which a large number of fine specimens havenbsp;been obtained, covers scarcely three acres of ground. In following the bluffsnbsp;to the station for a distance of about eight miles, although the exposures of the

red shale are frequent and of the same horizon, no trace of any fossil vegetable remains could be found by a party of three who were actively searching fornbsp;them in every direction. South of Fort Harker, on the Smoky Hill River, anbsp;locality discovered by Mr. Ch. Sternberg, who lives near by, is a small hollownbsp;where the red shales are full of leaves in a thickness of 8 to 10 feet; whilenbsp;out of this none have been found for a great distance. This hollow would notnbsp;cover, I think, half an acre of ground. The same remark has been made bynbsp;Prof. B. F. Mudge, of Manhattan College, who has for many years, as Statenbsp;geologist of Kansas, explored the Dakota group, studying its geological distribution and its paleontology with the greatest care. Some of the finestnbsp;specimens of its fossil flora have been discovered by him. In the Transactionsnbsp;of the Kansas State Board of Agriculture, the professor remarksd �� The fossilnbsp;plants are found at certain intervals of territory. In searching for them wenbsp;have frequently examined every visible outcrop for fifteen or twenty milesnbsp;wdthout finding a specimen; then, perhaps, a single square mile would furnishnbsp;several good localities. Our cabinet is represented by specimens collectednbsp;from twenty-five or thirty places from Washington County to Fort Lamed,nbsp;near the Arkansas, a distance of one hundred and seventy-five miles. Thenbsp;fossil plants are usually obtained from thin layers or strata, extending in anbsp;horizontal position along a ravine or around a hill. They may occur atnbsp;several places in the same vicinity, but usually without any connection. Thus,nbsp;in Clay County, near Riverdale, they were found at the bottom of a well asnbsp;low as the bed of the Republican, and on the top of an adjoining hill 200 feetnbsp;high, with numerous strata between, in which none could be seen. The deposits appear to have been local, dependent upon circumstances. Therenbsp;must have been, necessarily, an arm of the sea with soft, sandy mud, borderednbsp;by an adjoining dry land covered with a forest. The characteristic of thenbsp;local deposits indicate that the forests were on small islands scattered overnbsp;the Cretaceous ocean.�

The leaves, moreover, are not variously mixed, as they should be if they had been carried from any distance by currents or any other kind of motive-power ; but are generally found in groups of representatives of same or analogous species. For example: all the specimens of Juglans(%) deheyana sentnbsp;to me for determination are marked from two localities only; from Decatur,nbsp;Nebraska, twenty-nine specimens; and from three miles northeast of Fort

Harker, Kansas, six specimens. I have also found specimens of the same species at these two localities; on one hill near Decatur, I found no other kindnbsp;of leaves with them. Near Fort Harker, the leaves of this species are mixednbsp;with those of Laurus. All the specimens of Platanus ohtusiloha, twenty-twonbsp;in number, come from near Beatrice, Southern Nebraska. Representatives ofnbsp;this species have not as yet been found elsewhere. The specification of thenbsp;various forms of leaves of Sassafras, as may be seen in the descriptive part, isnbsp;confirmed by local distribution. Sassafras mirabile, S. cretaceuyn, S. liark-erianum are from Fort Harker; Sassafras mudgii and S. ohtusum from Salina.nbsp;Most of the Pterospermites, too, have been found at Fort Flarker. The Salinanbsp;locality is along the bluffs of the river formed by a succession of low hills,nbsp;whose faces are more or less abruptly cut and exposed by erosion. Two ofnbsp;these hills are separated by a narrow depression formed by a spring, and thenbsp;top of both is on the same level, as can be seen by the exposure of the uppernbsp;strata of red shale. One of them is strewn with fragments bearing specimensnbsp;of Menispermites obtusilobus, a species which I have as yet not seen fromnbsp;any other locality, though it is there in abundance; the other has only specimens of Sassafras. A distribution of this kind can result only from the proximity of the trees from which the leaves have been derived, and confirms thenbsp;opinion that the formation of the Dakota group is the result of muddy flatsnbsp;whose surface, raised perhaps in hillocks above water-limits, and already solidnbsp;ground, was cut like an immense swamp, here and there interspersed by rarenbsp;groups of trees and bushes. Of course the main portion of this surface wasnbsp;subject to continuous changes in the successive modifications resulting fromnbsp;the heaping and displacement of matter by water, and thus the leaves werenbsp;distributed either at the same places but at different levels, or at the samenbsp;level but at different localities.

The only objection to this supposition is the absence of roots or of fossil trunks, which as yet have been rarely observed in the shale of thenbsp;Dakota group.^ If we consider that the low islands bearing trees werenbsp;rare, and especially if we think how great is the disproportion in quantitynbsp;between trunks of trees with their roots, and the leaves which they bearnbsp;and disseminate annually for a series of years, we may easily account fornbsp;this apparent anomaly of leaves found petrified without accompanying trunks

^ Fossil silicilied wood has been found, however, in Nebraska, in the lowest strata of the Dakota group, and also at the upper part of the same formation. Near Sioux City, the shales are blackened bynbsp;the heaping of rootlets, as they are generally in the clay-bods preparing for the formation of peat.

and roots. It is, moreover, probable that the activity of life continued for procuring sustenance to the trees, has preserved the substance of the rootsnbsp;against the process of fossilization which acted upon the leaves ; for, indeed, these leaves are not truly fossil; they are merely printed on thenbsp;shales, but nothing of their substance has been left. The process of fossilization depends on local circumstances, and an indication of the incapacity fornbsp;this process, or of the absence of fossil petrifying elements in the shales of thenbsp;Dakota group, is the soft state of some fragments of wood in the deposits ofnbsp;roots and rootlets of Sioux City. These fragments have the consistence ofnbsp;decayed wood, and crumble in powder under the pressure of the finger.

These characters are the more easily and clearly exposed in a table marking the groups and genera to which the species are referable. Thenbsp;table comprises the genera admitted by Professor Heer, for the descriptionnbsp;of the species in PhyHites du Nebraska; those of Doctor Newberry, for thenbsp;leaves described in notes on extinct floras, amp;c., and those which I havenbsp;admitted for the description of species in this paper. The number markednbsp;after the generic name indicates approximately the number of species referrednbsp;to each genus:

5 L

The table indicates one hundred and thirty species, distributed according to descriptions in seventy-two genera, or about two species to each genus.nbsp;From this it would seem right to suppose, for the determination of the Cretaceous fossil leaves, a certain degree of reliable positiveness which could notnbsp;be expected of a flora with more numerous specific divisions. For, of course,nbsp;the species of the geological times were more numerous, perhaps, thannbsp;those of our own epoch, generally more contiguous, more or less illimitable ; subject, therefore, to personal criticism or opinions. The descriptionsnbsp;of the species of the Dakota group force a contrary conclusion. If some ofnbsp;the genera are clearly characterized and their relation positively ascertained,nbsp;some others may be considered as groups of analogous forms, which pointnbsp;to the derivation of different types, and which therefore cannot be considerednbsp;as homogenous or identical, though it may be difficult to divide them and tonbsp;limit the divisions by positive characters. Moreover, a number of thosenbsp;ancient leaves are not referable to any of the tyjjes of our present vegetation. They re*present apparently extinct vegetable groups, or their typical characters have been modified in such a way that by successive deviations from the primitive forms the relation of the offsprings cannot be recognized. This necessitates the admission of peculiar names in the descriptionnbsp;of these groups of leaves, {Populites, Menispermites, Phyllites, amp;c.,) whose affinity is merely supposed. The relation may be recognized hereafter, either

by the discovery of intermediate forms, or by the study of larger collections of living plants than those which I have at my disposal. It will be the task,nbsp;a pleasant one I hope, of other paleontologists to go further into the acquaintance with that most interesting Cretaceous flora of ours; to recognize its affinities better than I am able to do, and to correct errors of determinationnbsp;which are an unavoidable result of deficiency of materials for comparison.

The remarkable disproportion between the number of genera compared to species in the Dakota group seems at first to corroborate the system sonbsp;generally admitted now, of a successive development of vegetable forms according to a supposed rule of progression of more complex forms constantlynbsp;originating by the multiplication or subdivision of simple organs of inferiornbsp;types. For, according to this rule, the more we recede in our researches fromnbsp;the present floras toward the more ancient ones, the nearer we come to plantsnbsp;resuming, in organs of the simplest types, all the multiple characters whichnbsp;they are prepared to represent in a continuous series of divisions. In thatnbsp;way the old floras should be represented by simple generic forms and by onlynbsp;a few specific divisions slightly different from the generic characters. Thenbsp;uniformity or sameness of the facies of the Cretaceous flora, with its leavesnbsp;mostly entire, coarsely veined and coriaceous ; the difficulty of separating intonbsp;distinct groups, by fixed characters, the numerous forms of leaves which, seennbsp;separately, represent different species or even genera, and which, considerednbsp;in series or in groups, appear undividable into sections, and therefore as referable to a same genus, can be, also, admitted as a confirmation of the same hypothesis.

As long as we remain in the domain of suppositions, it is easy to go along in that way, and to ascend from one or more primitive forms for the buildingnbsp;up of a progressive scale of vegetables, by mere deviations or multiplicationsnbsp;of organs. But until we know more we have to consider the facts. And thenbsp;conclusion evidently forced, at least in considering the flora of the Dakotanbsp;group, is, that its disconnection from ancient types is so wide that even thenbsp;supposition of intermediate, unknown, extinct vegetable types fails to accountnbsp;for the origination of its peculiar characters.

sas and Nebraska are referable, for their upper part, at least, to the Permian, by their fossil remains of animals; but as yet no fossil plants have been obtained from them. The highest coal-beds in Kansas, those of Brownsville, fornbsp;example, have still in their shale species of ferns of the Carboniferous measures, not only the omnipresent species as Neuropteris loschii, N. hirsuta,nbsp;amp;c., but also Alethopteris serlii and Neuropteris rarinervis. In Franklinnbsp;County, of the same State, the coal also in the upper part of the Carboniferous measures is overlaid by an arenaceous shale, which has Asterophyllitesnbsp;equisetiformis, Pecopteris serrata, Lepidodendron, and other true Carboniferousnbsp;plants. Here is, for the western geological formations, the end of the flora ofnbsp;the Paleozoic times. Except the two species of Calamites recorded from thenbsp;Permian of the Rocky Mountains, no fossil vegetable remains have been foundnbsp;referable to a formation between the Carboniferous and the Cretaceous Dakota group. This remark could apply to the whole North American Continent, but for the few fossil plants known from the coal-measures of Ricbmondnbsp;and South Carolina, which by their characters are referable to the Triassic.nbsp;They mostly represent species of ferns with some large Equisetacece, Cy-cadece, and Conifers. And from what is known in Europe of the flora of thenbsp;formations between the Permian and the Cretaceous, the essential typesnbsp;which have marked the character of the vegetation, by the predominance ofnbsp;their remains, belong to the same families of plants. No trace of a leaf referable to a dicotyledonous species has been recognized anywhere before thenbsp;Cretaceous. And even until the discovery of the vegetable remains of thenbsp;Dakota group, it was generally admitted that the first dicotyledon had appeared in the middle or the Upper Cretaceous measures.

A glance over the table of genera named above, as representing the essential types of the flora of the Dakota group, is enough to show the prodigious difference which separates this flora from those of any former epoch, evennbsp;considering the antecedent vegetation of the Jurassic, known as it is fromnbsp;European specimens and European publications. The Ferns, Conifers, andnbsp;Cycadem, with a few species of Equisetacese, which constitute the whole floranbsp;of that epoch, are all of peculiar types, without relation to any of the speciesnbsp;of the same families recognized as yet in the flora of the American Cretaceous. Of Ferns, this flora has an Hymenophyllum and Sphenopteris, whosenbsp;affinity is with Hpmemphyllites furcatus of the Carboniferous, and still morenbsp;with a number of species of Hymenophyllum of our own time. Another

species of the same family, a Gleiclienia, is allied to species recognized in the middle Cretaceous of Europe, but fiir distant from either of the two species ofnbsp;this genus described from the Olithe. Of the Cijcadeoi one species from Nebraska is allied to a Pterophylliim, described and figured also from the Qua-der-sandstein of Grermany, but this last species, like ours, has no known relation to any fossil or living plant of this genus, and therefore is not positivelynbsp;referable to this family. In the Conifers the Cretaceous flora of Nebraskanbsp;has representatives of Sequoia, Glyptostrobus and Gunninghamites ? perhaps.nbsp;The first two have not been seen anywhere before the Cretaceous, and thenbsp;last only in the Miocene. The fragments considered by Dr. Newberry asnbsp;representing an Araucaria are closely related to a species of Conifer describednbsp;formerly by Dunker, under the name of Abidites curvifolius from the Quader-sandstein of Blankenbourg. The relation of this form is rather with Abiesnbsp;than with Araucaria. Admitting it, however, in the section Araucarice, whichnbsp;after being recognized in the fossil wood of the Devonian, disappears entirelynbsp;as far up as the Jurassic, where it is represented by four species, it is stillnbsp;impossible to find even a distant affinity between the supposed Cretaceousnbsp;Araucaria of ours and any of the forms of older formations. The relation of thenbsp;genus Phyllocadus is with that of Salisburia in the section Taxacece. It isnbsp;represented in the flora of the Dakota group by one species, and has not beennbsp;seen before in a fossil state. All the Salisburia fossil species are as yet fromnbsp;the Miocene of Europe, and from the Eocene of this continent. So far, this isnbsp;all that can be said of the relation of the flora of the Dakota group with anynbsp;of the vegetable remains recognized from precedent epochs, and it is indeednbsp;very little. It is possible, of course, to suppose an intermediate and unknownnbsp;land formation, where, in an immense space of time, the plants of a lowernbsp;grade have developed those primitive types and multiplied them to thenbsp;Cretaceous epoch. But the Cretaceous flora does not preserve any traces ofnbsp;ancient forms known of old; of the ferns, large Catamites, Cycadece, amp;c., notnbsp;even a predominance of ferns and Conifers, which were remarked in the Ju-rassic as it is known until now. Among its 130 sj^ecies, the Dakota groupnbsp;flora has only five species of ferns or Cryptogamous plants; one single speciesnbsp;very doubtfully referable to the Cycadece; six species of Conifers, two Monocotyledons; all the others represent Phosnogamous plants, distributable notnbsp;in a single one, but in all the essential groujis of vegetables living at our time.nbsp;Of the Apetalous plants it has the Itoidece, Amentacece, Myricacece, Platanece,

Salicinece; groups represented, indeed, in a large proportion, but not larger than in the vegetation of the present time. Of the Gamopetalous, it has thenbsp;Bicornes, Ebenacece, amp;c. Of the Poljpetalous, the Magnolm, Menispermacm,nbsp;SapindacecB, amp;c., and therefore it has representatives of all the classes of ^dantsnbsp;without disproportion in one degree or the other, as compared to what is considered the scale of the vegetable kingdom. This seems to prove a collateralnbsp;development of different primitive types, and therefore the appearance atnbsp;certain epochs of those original forms which, at each geological period, havenbsp;changed the character of the vegetable world, and which do not have anynbsp;connection with antecedent types. On this point of view, it is evident thatnbsp;the flora of the Dakota group is as widely disconnected from that of the Jurassic, even of the Lower Cretaceous, or as distincly original, as are the floranbsp;of the Carboniferous compared to that of the Devonian, or the Permian typesnbsp;compared to those of the Cretaceous.

The specimens from which this flora has been studied until now have been obtained in different localities over the whole extent of the area coverednbsp;by the formation, from the 39� to the 47� of north latitude. In this spacenbsp;of 18� the general facies of the vegetation has been apparently preservednbsp;without marked changes in relation to latitude. At least the evidencenbsp;of a variation indicating atmospheric differences in the distribution of whatnbsp;might be called northern and southern types, is not positive enough to benbsp;considered as in correlation with the vegetable distribution of our presentnbsp;time. The specimens obtained from Minnesota by Prof Jas. Hall representnbsp;a greater proportion of crushed fragments of conifers, stems, and cones especially, of which a few seeds only, doubtfully referable to the genus Cunning-Tiamites, PresL, are recognizable. With these they have fragmentary leavesnbsp;of Laurus, of Lyriodendron, Sapotacites, Ficus, Andromeda, referable to thenbsp;species published from the specimens of the Blackbird Hills of Nebraska, bynbsp;Doctor Newberry and Professor Heer. These same paleontologists havenbsp;also described, from North Nebraska, species of Platanus, Populus, Diospiros,nbsp;lihamnus, Quercus, Fagus, Sassafras, Proteoides, Magnolia, Lyriodendron,nbsp;and Acer or Acerites. All these genera are also represented in the specimensnbsp;of Doctor Hayden, from Decatur, and some of them also by the leaves whichnbsp;the same geologist has collected in South Nebraska, Lancaster and Gage

Counties. These represent more especially species of Populites, Platanus, Quercus, and Betula. The same genera are all recognized in the specimensnbsp;from Kansas, with the exception of Populus, Salix, Ehamnus, Betula, Fagus,nbsp;while Kansas has exclusively as yet representatives of the genera Liquidanibar,nbsp;Creclneria, Domheyopsis, Pterospermites, and Aralia. The distribution, according to species, is also somewhat different in Kansas and Nebraska. Thenbsp;north has very few leaves of Sassafras, and these represent one species only;nbsp;while in Kansas, especially near its southern limits, a large portion of thenbsp;fossil-leaves belong to five species of this genus. Per contra, the leaves referable to Laurus are more and more numerous toward the north in Nebraskanbsp;and Minnesota, where also are found in larger proportion the leaves referablenbsp;to Quercus, which there represents five species, while one only is describednbsp;from Kansas specimens. In considering these differences in the distributionnbsp;of typical forms, and the general facies imprimed to the flora by this distribution, one might suppose that the flora of the Dakota group indicates in Kansas, by its character, a higher degree of temperature. This supposition receives some authority from the luxuriance of the vegetation, marked in Kansasnbsp;by Crednaria, Pterospermites, and Domheyopsis, genera represented as yet innbsp;this State only, and all with leaves of large size ; and by the difference in thenbsp;proportion of the leaves of species of some genera common to both States.nbsp;The species of Platanus, for example, P. newherrii, P. obtusiloba, recognizednbsp;in Nebraska, have smaller leaves than Platanus heer�, of Kansas. The twonbsp;species of Liriodendron, of Nebraska, are of a very diminutive type comparednbsp;with that of L. giganteum, of Kansas. Sassafras mirahile, of Kansas, hasnbsp;leaves measuring more than one foot in diameter, while S. creteceuin, of Nebraska, is represented by small leaves. These differences may be ascribablenbsp;to local circumstances, to more or less favorable exposition, to a more fecundnbsp;composition of the ground, amp;c., rather than to a general atmospheric deviation. This seems to be proved by observations of a more general character.

Considered as a whole, most of the types of the Dakota group, related to those of our present flora, represent a moderate climate, like the one prevailing now between the 30� and 45� of latitude north. The vegetable typesnbsp;more distinctly characterized by their leaves, and which are recognized bynbsp;all the paleontologists, Salix, Fagus, Platanus, Sassafras, Aralia, Magnolia,nbsp;Liriodendron, Menispermum, Paliurus, Rhus, amp;c., are all co-ordinate to identical climatic circumstances, or to the same average temperature which

governs at our time the,vegetation of the latitude indicated above. All these types are, therefore, present in the North American flora, some of themnbsp;with scarcely any alteration of forms.

Professor Heer has the same opinion in regard to the climate of the upper Cretaceous epoch of Grreenland as indicated by its flora. He is justnbsp;now publishing two memoirs, which, besides their great scientific importance,nbsp;and merely considering the question of the relation of the floras to temperature, are of high general interest. The first describes a group of fossil plantsnbsp;from the lower Cretaceous of Greenland, representing thirty-eight Fucoids,nbsp;one lycopodiaceous species, three Equisetacem, nine Oycadem, seventeen Conifers, five monocotyledonous, and one dicotyledonous species. These vegetable remains, according to the author, represent types of a tropical or subtropical flora, and this under the 70� of north latitude. There is evidently nonbsp;relation whatever between this low Cretaceous flora and that of the Dakotanbsp;group. But in a second memoir, the author describes an upper Cretaceousnbsp;flora of the same country, which, in its essential types, appears identical withnbsp;that of the Dakota group. It has 28 species of the genera Populus, Myrica,nbsp;Ficus, Sassafras, Proteoides, Credneria, Andromeda, Dermatophyllite^, Diospi-ros, Panax, Chondrophyllum, Magnolia, Myrtophyllum, Sapindus, Rhus, Legu-minosites} genera, which, with few exceptions, are represented in the Cretaceous North American flora. What a difference in the types of these twonbsp;groups of plants from the same locality and of the same formation, one withnbsp;74 species, 42 of which are cryptogamous plants, 26 phenogamous gymnos-perms, among which are nine Cycadese, indicating tropical climate, and onlynbsp;one dicotyledon; while the other represents only 28 species distributed in 16nbsp;genera, all dicotyledonous and of types analogous to those of the present Northnbsp;American flora. The distribution of such a small number of species in sonbsp;many genera of distant affinity is, by itself, a fact of great weight in considering the succession of types in their relation to geological periods, and confirmsnbsp;the remarks at the close of the former chapter,� But it is still more remark-

�New and important information comes just now in confirmation of this remark. From a letter of Coiint Saporta, the most ancient flora of the Cretaceous of Bohemia, whose position is similar to that ofnbsp;the Dakota group, or at the base of what the German geologists call the qnadorsandstein, hero immediately overlying the primitive formation, is composed mostly of dicotyledonous leaves whose forms arenbsp;remarkably analogous to those of the Dakota group flora. The celebrated paleontologist of Franconbsp;remarks tlnit with the dicotyledonous leaves the specimens represent only one species of Conifers ; thatnbsp;the dicotyledonous leaves are large and of varied forms, all apparently representing new types whosenbsp;exact determination will he the more difficult that they evidently represent synthetic types, resuming,nbsp;perliaps, each one, the character of a whole family, and appearing as intermediate links between manynbsp;groups of our present order of vegetation, iamp;c.

able to see, at two horizons of tlie same formations, the resjiective floi'as denoting so great a ditference in the atmospherical circumstances which have governed the distribution of each.

It seems evident, from what has been formerly said of the grouping of leaves of the same kind upon separate and limited areas of the Dakota group,nbsp;as also of their generally flat position in the sandstone or upon the shale, thatnbsp;the trees from which the fossil remains are derived have grown in the samenbsp;localities where the fossil leaves are found. These leaves cannot have beennbsp;carried down torrents and rivers from mountains whose altitude could accountnbsp;for the climatic differences. They do not either represent a kind of transportation by floating islands, like those which are carried down the Amazonnbsp;Kiver and sunk near its mouth ; they are true representatives of the climatenbsp;of that epoch. In regard to the Cretaceous floras of Greenland, and to thenbsp;atmospheric modifications indicated by their characters, we can as yet saynbsp;very little. The facts and their causes will have to be discussed by the celebrated author who has had under examination the specimens representingnbsp;the two groups of plants. And we may be certain that the question will benbsp;fully considered by him. I shall be permitted, however, to present these fewnbsp;remarks: 1st. Admitting the relation of the flora of the Dakota group withnbsp;that of the iqiper Cretaceous of Greenland, a relation which, though recognized as yet by generic affinity only, appears sufficiently close to authorizenbsp;the conclusion that both have been affected by identical conditions of temperature, supposing, also, a contemporaneity of the formations, we mightnbsp;easily account for this relation by the well-known fact that the isothermalnbsp;zones are wider in proportion to the age of the formations, a fact resulting mostly from a greater proportion of atmospheric humidity. The samenbsp;reason has been surmised already for explaining the identity of a number ofnbsp;species of the Western Tertiary, especially of the lignitic measures of Carbonnbsp;and Evanston, with those of the Mioeene of Greenland.^ 2d. The cause otnbsp;the modifications of climate, either slow and continuous during a period ofnbsp;time, or remarked from different formations of the same epoch, result from thenbsp;changes of land surface which modify in a corresponding degree the intensitynbsp;or direction of the elements which enter into the composition of the atmosphere. A case serving to illustrate this, is remarked in passing upwardnbsp;from the flora of the Dakota group to that of the Eocene of the Docky Mount-1 Dr. F. V. Hayden�s Ecport, 1871, p. 312.

ains. The Dakota group, resting upon Permian land, or deposited upon its shores, was under the influence of a land climate at the end of a stationarynbsp;period of long duration. Its climate was accordingly dry, and proportionallynbsp;cold. A long period of subsidence covered it, to the west at least, by a succession of deep marine formations recorded in the different stages of the Cretaceous strata. At the opening of the new epoch, the Eocene sandstone, fullnbsp;of fucoidal remains, is brought up to the surface of the sea. The first landnbsp;that covers it is still, like the low land, under an atmosphere of vapors. Thenbsp;climate is proportionally warm, or at least the mean temperature is higher,nbsp;and the vegetation appears in exact relation to these atmospheric circumstances. It is a time for a luxuriant vegetation of ferns, of palms, of thenbsp;boggy plants which favors the growth of peat, and the heaping of vegetable matter in a succession of beds which have afterward been decomposednbsp;into coal. That this vegetation has no relation whatever with that of thenbsp;Dakota group is a matter of course, as it is born or established under totallynbsp;different influences and circumstances. The difference between the flora of thenbsp;Dakota group and that of the formation which I call Eocene is, therefore,nbsp;attributable to a change of climatic influences, rather than to difference of age,nbsp;a conclusion admittable for all the changes indicated by geological floras.nbsp;But on this assertion, and especially in regard to its application to the florasnbsp;of the Tertiary groups of the West, nothing more can be said until the fossilnbsp;plants of these formations are published, a work prepared for another volume.nbsp;I reserve for that time also, the discussion on this new hypothesis: thatnbsp;groups of identical fossils, especially vegetable ones, do not prove or indicatenbsp;contemporaneity of the formations which they characterize, when these formations are observed at great distances or under different degrees of latitude.

It is not possible to attach any importance to the priority of nomenclature of so-called species of fossil plants, as long as they are known from mere descriptions. The analogy, not to say the specification, of fossil leaves is uncertain enough when the descriptions are illustrated with carefully madenbsp;drawings or figures which clearly define the essential characters, the outlinenbsp;or general forms, with the nervation of the leaves. In the written records ofnbsp;vegetable fragments, even of whole and well-preserved leaves, the descriptions, though exact they may be, are always subjected to erroneous representations of the mind. For the same reason, I consider not only as a right.

but as a duty, to modify names and descriptions of fossil species which I may have published formerly, whenever this change is demanded either by thenbsp;discovery of more perfect specimens, which may show under another lightnbsp;the relations of a plant, or by the recognition of different characters whichnbsp;were not observed in a preliminary examination. The first specimens furnished me were comparatively few, mostly incomplete, and I was requestednbsp;to make an examination of them and to describe them, at least in a precursory way, in a very short time. They were the materials from which wasnbsp;written and published in the American Journal of Science and Arts, vol. xlvi,nbsp;July, 1868, the paper on some Cretaceous fossil plants from Nebraska. Sincenbsp;that time I have not only received a large number of specimens from thenbsp;Dakota group, but at two different times I have been over the field fornbsp;the purpose of studying the distribution of the fossil plants, their relation tonbsp;localities, amp;c., and have had opportunities of collecting a number of specimensnbsp;in a better state of preservation, and, what is still more advantageous for thenbsp;exactitude of the determination of fossil plants, to compare in place differentnbsp;forms related to the same species. Of course these prolonged studies andnbsp;the increasing amount of materials may^ already account for, and render excusable, some difference in the specifications and the synonymy remarked innbsp;the following descriptions.

Moreover, at the time when the first descriptions of these fossil plants were made, there was nothing as yet known of the dicotyledonous Jeaves ofnbsp;the Cretaceous, either of Europe or America, except the little which hadnbsp;been published in the Paleontographica, by Stiehler, Zenker, and Dunker,nbsp;and in the Phyllites cr�tac�es du Nebraska by Heer. As remarked by thisnbsp;author. Debey, who has a large collection of leaves of the Cretaceous of Aix-la-Chapelle in Belgium, had admitted that our fossil leaves of the Dakota groupnbsp;had no relation whatever with those of Belgium, and that therefore no comparison could be made between them. Since that time. Professor Etting-hausen has published, on the Cretaceous flora of Niedershoena of Saxony,nbsp;what he calls a Contribution to the acquaintance of the oldest dicotyledonous plantsnbsp;of our earth, and Heer, also, has given on the Cretaceous flora of Moletin, innbsp;Moravia, and on that of Quedlinburg, two very fine quarto memoirs, affording,nbsp;like that of Ettinghausen, a few points of comparison for the present studynbsp;of the flora of the Dakota group. Notwithstanding this supplement of mate-

rials, it is certain that this flora is still very imperfectly known in its essential characters and its diversified forms.

A valuable assistance has been given me in the revision of this memoir, and since the engraving of the plates, by Count Saporta, of Aix. An examination of the first proofs of the plates suggested to him, on the relation ofnbsp;some leaves, important remarks which have been used for the distribution ofnbsp;the groups and the limitation of some genera. The thankful acknowledgment of this cordial assistance is as pleasant to me as has been the exchangenbsp;of views and the intercourse with a paleontologist of so high a standing andnbsp;so justly celebrated.

Frond flat, membranaceous, dichotomous, branching in an acute angle of divergence; divisions as broad or broader than the main axis, linear, entire, obtuse, slightly enlarging upward.

Fucoides digitatus, Brgt., Flist. d. Veg. foss. p. 69, PI. ix, Fig. 1.�Zonarites digitatus, Geinitz, Dyas., PI. xxvi.�Lesqx. in Hayden�s Report, 1872,nbsp;p. 421.

Our specimen is less complete than the one figured by Brongniart. It is broken on one side, and merely represents two of the divisions of thenbsp;plant. These, one cent, broad, slightly enlarging upwards, diverging undernbsp;an angle of 20�, are apparently of thin membranaceous texture, merelynbsp;marked by the irregularities of the surface of the calcareous clay over whichnbsp;the plant is preserved. No difference is observable between this and thenbsp;European form, except in the slightly broader size of the divisions. Thenbsp;main axis has the same character as the branches, slightly enlarging fromnbsp;the base upwards.

The relation of these remains has not yet been positively ascertained. Schenk, in Paleont. xi, p. 301, compares it to Cyclopteris digitata, Brgt.,nbsp;a fern of the Oolithe. Schimper, Pal. Veget., p. 186, rejects this opinionnbsp;from anomaly of characters, and would consider it as referable to the genusnbsp;Jean-Paulia, Ung., which, too, represents species of uncertain affinity relatednbsp;to ferns. The association of these fossil remains with those of animals ofnbsp;deep marine water, large Ammonites, Baculites, Inocerami, is a sufficient indication of their submarine origin, and if they represent a plant it is truly a

Fucoid. It may be, however, a kind of sponge, as it resembles some tubulose species of this class by its punctate or perforated-like surface, an appearancenbsp;which, as remarked above, may be due to the porous compound of the matrix.

Habitat.�Niobrara group of the Cretaceous, about 100 feet above the top of the Dakota group, six miles north of Fort Darker; on the highest pointnbsp;of the divide between Saline Fork and Smoky Hill River. It is there mixednbsp;with a prodigious quantity of fossil shells. It is the only species describednbsp;in this paper from out of the Dakota group. In Europe it has been recognized in the Dyas or Permian.

Pinna linear from the truncate base to the niidclle, enlarged and lohed upwards from the forking of the medial nerve; veins broadly oblique, distinct, simple or branching from the base.

This fragment of a fern, too small for exact determination, was doubtfully referred at first to a Lygodimn, though I do not know of any species of this genus to which it may be related. Of all the ferns which I have beennbsp;able to compare, none ajipears to have any marked analogy with it butnbsp;Trichomanes pinnatum, Schwartz, and this only by the characters of its lowestnbsp;pinnae. The frond of this species, which inhabits the northern tropical regions from Mexico to Brazil, is lanceolate in outline, simply pinnate, withnbsp;linear pinnae in the fertile state and oval lanceolate ones in the sterile fronds.nbsp;In these, the lowest leaflet is often enlarged and lobed from the middle upward, by the forking of the medial nerve, exactly as in the fossil fragment.nbsp;The analogy is rendered more marked by the disposition of the veins, which,nbsp;in the living species are fine, very close, distinct, simple, or branching, goingnbsp;out in an open angle from the thick costa, with exactly the same degree ofnbsp;divergence as seen in the fossil species. The fossil fragment, however, isnbsp;of a coriaceous texture, while Trichomanes species are more generally thinnbsp;and membranaceous. The degree of relation cannot, therefore, be positivelynbsp;ascertained without better specimens.

Frond membranaceous or subcoriaceous; pinm� linear oblong, pinnately divided into oblanceolate or cuneiform alternate oblique pinnules, deourring to tbe convex slightly winged rachis more or lessnbsp;deeply bi-trilobate; lobes obtuse, simple nerved.

As seen from the figures, we have three specimens of this species. The one. Fig. 3, represents a narrow linear lanceolate pinna with alternate pinnulesnbsp;more closely approached towards the point; the second. Fig. 4, represents annbsp;upper or terminal lobe of an apparently larger pinna. The third is of thenbsp;same character, with longer narrower lobes. These fragments indicate anbsp;species variable in its modes of division and in the size of the pinnules, which,nbsp;however, have the same general form and the same nervation. The texturenbsp;of this fern appears thickish, subcoriaceous; the nerves and their dichotomousnbsp;simple branches are well marked, and ascend to the upper borders of eachnbsp;pinnule, which they sometimes mark by depression into a small notch. Nonbsp;species related to this has been deseribed, though it may be compared tonbsp;Sphenopteris Johnstrupi, Heer, of the Cretaeeous flora of North Greenland,nbsp;Arc. FL, p. 78; PI. xliii. Fig. 7. Its analogy is rather with species of thenbsp;section of the Sphenopteris hyrnenophylloides, mostly represented in the Carboniferous measures, and still more with a number of species of Hymenophyllumnbsp;of Cuba, or of the north tropical region of this continent.

Dr. Newberry, in Notes on the extinct Jloras, amp;c., p. 10, has described as Sphenopteris corrugata, a species which, from the description, at least, seemsnbsp;related to this one.

Pinua coriaceous, linear lanceolate obtuse, alternately equally lobed; lobes more or less disjointed, turned outside, obtuse; medial vein tbin, undulating ; divisions alternate and alternately branching innbsp;simple veinlets, ascending to the borders.

The small branch, a pinna, represented by the specimen is 2 centimeters long, 8 millimeters broad, near the abruptly attenuated base, 4 millimeters near the obtuse point; cut in obtuse lobes, the four inferior ones disjointed to below the middle, enlarging upwards to a very obtuse point andnbsp;turned outside, the upper ones conneeted nearly to the borders, which arenbsp;slightly crenate, by the impression of the veins or the wrinkled surface of thenbsp;pinna; secondary veins alternate, decurring to the middle one, which theynbsp;join in a very acute angle, alternately pinnately and simply branching twicenbsp;on each side, rarely thrice, the branches ascending to the borders.

I find this species figured, not described, in Flore fossile de Sezane, by Sap-orta, p. 332, with the remark that it is still inedited. The fragment from which

our figure and description is made is much like that figured by Saporta. There is, however, some difference in the more deeply disconnected lobes; in thenbsp;slio-htly crenulate borders, a character which may be caused by the wrinklednbsp;surface of the leaflets; especially in the disposition of the tertiary vineletsnbsp;more evidently alternate, and of the secondary ones more decurrent thannbsp;marked by the enlarged figure of the author. Our fragment has also asnbsp;evident a degree of likeness by the form of the leaflet to Rapha�lia neurop-teroides, Deb. et Ett., as figured in the Acrohyren of the Cretaceous of Belgium,nbsp;PI. V, Fig. 20, and by its nervation to the same species as figured enlarged,nbsp;PI. iv. Fig. 25. Indeed, it seems that the American form is not specificallynbsp;distinct from the Belgian one, which by its different fragments indicates anbsp;fern with a polypinnate frond and variable divisions.

Frond pinnately divided; pinnae long, linear, pinnately equally lobed; lobes nearly at right angles to the racbis, separated to near the base; medial nerve thick, pinnately branehing; veins forking at thenbsp;middle.

Gleiclienia kurriana, Heer, Flora v. Moletin, p. 6, PI. ii. Figs. 1-4.� G. kur-

Though the branch of fern described here much resembles the species described by Heer, by the form of its pinnules disjoined to below the middlenbsp;by a narrow obtuse sinus, identity of both these forms is, however, doubtful.nbsp;The difference in the characters is more marked between the Americannbsp;specimen and those of Moletin, than with a small fragment of a pinna published also by Heer from the Cretaceous formations of Quedlinburg, andnbsp;which the author refers with doubt to the same species : Quedl. Flora, p. 5,nbsp;PI. 1, Fig. 3-4. The specimens from Moletin, however, are fructified whilenbsp;these last are sterile, and this may account for the difference of the facies.nbsp;From the Moletin specimens the American form essentially differs by proportionally shorter, broader, more obtuse pinnules, more open too, or nearlynbsp;at a right angle to the rachis, and from both the E uropean specimens, by thenbsp;forked secondary veins, which are marked simple in the descriptions and figures of the author. By this character our American species or variety wouldnbsp;be more closely related to Didymososorus comptoniifolim, Deb. et Etting., a species from the Cretaceous of Aix-la-Chapelle, which, with a somewhat likenbsp;form of pinnules, has its veins also forked. The facies of this last fossil fern

represented in Kreide flora von Aachen, PI. i, Fig 1-5, is, however, ditferent, the lobes being shorter, less distinctly divided, and rather turned upwardnbsp;than horizontal. As Heer separates his species from the Belgian one, especially on account of the veins being simple in the Moletin specimens, whilenbsp;they are sometimes forked in those of Belgium, (for the figure a representsnbsp;them simple, except the two lower pairs of two of the leaflets,) and as in thenbsp;American form all the veins are forked, while it has the same facies as thenbsp;Quedlinburg specimens, I believe that all these Cretaceous fragments represent the same species. For this reason I do not wish to increase the numbernbsp;of species from characters of little importance and rarely permanent in thenbsp;ferns of this group.

Frond large, coriaceous, Ui-tripinnately divided; pinntB linear or enlarged in the middle, pinnately, alternately divided in lanceolate, pointed, entire, open, erect pinnules, disjointed to the decurring base,nbsp;which forms a narrow wing along the narrow raohis or medial nerve; nervation pinnate; secondarynbsp;veins simple, alternate, parallel, turning upwards in ascending to the borders, which they' follow in anbsp;series of curves.

This beautiful species is represented by a number of specimens, the largest of which. Fig. 1, shows the point of three apparently parallel pinnmnbsp;3^ centimeters wide, cut down nearly to the rachis into erect patent, simple, linear lanceolate, entire, sharply-pointed segments, decurring by their base andnbsp;forming a narrow border along the rachis to the point of union with a lowernbsp;segment. These lobes, mostly equal in length upon the same pinnae, are fromnbsp;2 to 5 centimeters long, and from 3 to 8 millimeters broad. The nervation isnbsp;remarkably similar to that of some dicotyledonous leaves; the lateral or secondary simple veinlets in an acute angle to the middle nerve, (40�) are close tonbsp;each other, 2 to 3 millimeters distant, parallel, ascending in curving upward tonbsp;the borders, which they follow and join the upper veins, forming successivenbsp;bows or festoons. The veins are generally simple, separated often by Tertiary shorter vinelets which disappear toward the middle of the principalnbsp;areas into large areolae, by dividing on both sides. The relation of this fernnbsp;to Todea, a genus of the section of the OsmundcecB, is indicated merely bynbsp;tlie form and mode of division of the pinnae; but the neuration is differentnbsp;from that of any of the living species of this genus, even from any species ofnbsp;ferns of our time. It is comparable to Monheimia aquisgranensis, Dev. andnbsp;Ett., Acrohryen, p. 31, PI. iv and v. Fig. 6. Of course the exact relation of

this fern cannot be positively known as long as its fructification has not been discovered.

Frond linear, simply pinnate j racliis rugose, half an incli broad or more, marked by circular dots'in vertical rows and regularly placed about half a centimeter distant, apparently scars of the points ofnbsp;attachment of tho pinna); pinna) entire, oblong, oval-obtuse, slightly arched on the lower side, flat,nbsp;attenuated at the round point of connection to the rachis, regularly and narrowly striated lengthwise.

Pterophyllum harjde,mi, Lesqx. in part, American Journal of Science and Arts, loc. cit.^ j). 97.

In the paper above referred to, I considered the fragments here described, together with a cone, as referable to the genus Pterophyllum from their likeness to vegetable organs of the same kind described and figured by Stiehler,nbsp;in Paloeont., vol. v, p. 76, PI. xv. Figs, a and d, under the name ofnbsp;Pterophyllum ernestince. I have seen nothing since, in the publications ofnbsp;recent authors, which might give any clue to the true relation of this vegetable. Its parts as represented. Figs. 6 and S'*, are evidently related by theirnbsp;form and characters to Stiehler�s species, and referable at least to the samenbsp;genus, the frond merely differing by the pinnae attenuated at the base andnbsp;not sessile in their whole width; by the smaller size of these pinnae and thenbsp;slender close striae with which they are marked. In considering Stiehler�snbsp;siiecies, Schimper only remarks, in Pal. Veget., p. 139, that probably this vegetable should be separated from the genus Pterophyllum, on account of thenbsp;thickness of the rachis. But the plant is left by him with species of uncertain affinity. The cone, too, by its likeness to that of Stiehler�s, Fig. d, wasnbsp;for the -same reason referred to the same kind of vegetable. I have followednbsp;1 lofessor Heer�s advice in separating it as rather referable to Conifersnbsp;Habitat.- Near Decatur, Nebraska, Hayden.

Cone oblong, abruptly narrowed to a short pedicel, scales broad, truncate, appressed and imbricated in spiral.

Pterophyllum haydenii, Lesqx. in part, American Journal of Science and Arts, loc. cit., p. 91.

This cone, as remarked above, was at first referred to Pterophyllum haydenii, from its likeness to that which is described by Stiehler, Paleont., vol. V, p. 76, PL XV, Fig. d, under the name of P. ernestince. With us, as innbsp;Germany, the fragment of the cone was found in the same locality as thenbsp;specimens of the fronds and leaves; but not in close connection. Thesenbsp;casual circumstances do not afford sufficient authority to consider as identicalnbsp;with a branch of Cycadem a strobile referable by its characters to the pinenbsp;family. Stems and leaves of Abies or of Araucaria have also been found innbsp;the Cretaceous of the Hartz Mountains, the quadersandstein of Blankenburg,nbsp;as also in the Dakota group. Dunker, in Paleont., vol. iv, p. 180, describes, under the name of Abietites, three species, two of which, A. curvi-folms et A. hartigi, PI. xxxiii. Fig. 1-2, bear leaves more or less curvednbsp;inward and enlarging upward to an obtuse point. Dr. Newberry, innbsp;Notes on extinct floras, p. 10, describes from Sage Creek, Nebraska, fragments of branches bearing broadly spatulate obtuse leaves under the name ofnbsp;Araucaria spathulata, which appear related to Dunker�s species. In considering, therefore, the relation of habitat, we have the same authority for referringnbsp;this cone of Cretaceous age to Conifers as to Cycadese. The description cannot add much to what may be seen on the figure. None of the scales seemnbsp;to have been preserved entire; they are broadly oval or rounded smooth,nbsp;truncate at the top, an appearance due probably to the erosion or destructionnbsp;of part of the scales. As the stone wherein the fragment is imbedded is verynbsp;hard, it was not possible to see anything of the seeds, if there are any, coverednbsp;by these scales..

Cone spindle-shaped, tapering upward and downward about in the same degree; scales closely oppressed, rhomboidal.

Sequoia formosa, Lesqx., American Journal of Science and Arts, loc. cit., p. 92.

The cone is centimeters long, 1^ centimeters broad in its widest part, below the middle, tapering upward to a point and downward to a short slendernbsp;peduncle. The scales, as seen Fig. 9'� enlarged, are rounded in the upper part.

narrowed downward to an obtuse point, surrounded by an inflated margin or thick border, and marked in the central space by wrinkles diverging from anbsp;small round point under the upper border. The width of these scales is aboutnbsp;4 millimeters each way, being, however, especially in the upper part of thenbsp;cone, a little more expanded on the sides and broader than long.

The reference of this fine cone to the genus Sequoia is not positively ascertained. By the position and the form of its scales, it resembles the cones described in Sternb., Flora der Vorwelt, (vol. ii, p. 184, PL xlix. Figs. 2�'� and 3,)nbsp;under the name of Bergera ininuta, a species which is represented by betternbsp;specimens under the name of Cunninghamites sternbergii by Ettinghausen, innbsp;his Kride Flora Von Nieders., (p. 12, PI. i. Figs. 4-6.) The cones of thisnbsp;species, however, are proportionally shorter and broader, more obtuse, sometimes nearly rounds and the scales, more enlarged in the middle, do not appear marked by an inflated border. In my description, loc. cit., I comparednbsp;this cone to Araucarites sternhergi, Gopp., as figured in Heer�s Urwelt dernbsp;Schweitz, p. 310. This species is a synonym of Steinhauera minuta, Sternb.nbsp;(loc. cit., vol ii, p. 202, PI. Ivii, Figs. 7-15.) The relation, however, is disproved by the same degree of difference as with the former species, thenbsp;scales being in Sternberg�s species more enlarged on the sides, without anbsp;border, and the cones still more obtuse and pi'oportionally broader. No fossil cone described as yet, to rny knowledge at least, has such a tapering conical form as ours, except the Lipidanthium microrhombeum, Schp., figured innbsp;Schenk. Foss. Flora, d. Grenzsch, (PI. xxxii. Fig. 8,) which is considered asnbsp;the inflorescence of some Cycadese.

Cone smal], obloug-oval; receptacles oval-pointed at both ends ; foliaceous scales crumpled, deejily imbedded in the stone, seeds small, oval-oblong.

1 he cone is cut vertically, and its axis, like the receptacles of the seeds and their follicles, is exposed to view. It is narrowly oval, narrowed to thenbsp;slender peduncle, a little more than 1^- centimeters long and 1 centimeternbsp;wide. The receptacles are empty, but distinctly cut into the stone as innbsp;Fig. 10'� somewhat enlarged ; the scales and follicles are vertically and deeplynbsp;imbedded, and their shape undistinguishable The axis is marked with deepnbsp;perforations indicating the points of attachment of the receptacles.

I should have been disposed to separate this cone, as representing a distinct species, on account of its slender axis, slender branches, and shorter, more open, and close receptacles; hut these characters are not of positivenbsp;sj^ecitic importance, and as we do not know the leaves of this Conifer, nor thenbsp;form of the scales of the strobile, they do not authorize a multiplication ofnbsp;nomenclature, especially in this case, where Heer�s species has been alreadynbsp;described in its different forms under six generic or specific names. Therenbsp;is also a probability of identity of species in this fact, that S. reichenbachi hasnbsp;been described from the Upper Cretaceous of Greenland, whose flora, fromnbsp;recent discoveries, seems to be closely related to that of the Dakota group.nbsp;It should be remarked, however, that Heer refers to his species Cunning-hwnites sternbergii, Etting., to wliich I have compared the former species,nbsp;recognizing positive difference. Now, this broken cone of our Cretaceousnbsp;bears in its general form and size the same relation to 8. reichenbachi as thatnbsp;of Sequoia formosa bears to the cones described by Ettinghausen. If, therefore, the European forms belong to the same species, 8. reichenbachi, the conenbsp;of ours. Fig. 10, is different and may represent a crushed dry cone of 8. for-mosa. The relation of these strobiles cannot be positively recognized asnbsp;long as the leaves and scales are unknown. .

Branches fastigiate, very slender, thread-like, much divided; leaves imbricate, appressed, embracing at the base, linear lanceolate, more or less abruptly pointed; cone narrow, cylindrical.

The specimens where this small species of Conifer is preserved are irregularly covered or perforated in various directions by the deep impressionsnbsp;of thread-like branches, scarcely 1 millimeter thick, round and knotty bynbsp;the base of the leaves, which appear as placed in whorls or by four. Thenbsp;branches are irregular in their divisions, either alternate or opposite, ornbsp;one-sided, of various length, erect, crowded, with leaves closely appressed,nbsp;imbricated and biform, either linear, lanceolate, sharply pointed, or shorter,nbsp;more abruptly pointed and slightly obtuse, without trace of a medial nerve.nbsp;As seen in the figures lid to � much enlarged, the lower part of the leaves

seems slightly narrowed from the middle downward, an appearance resulting from their concavity in the embracing of tbe stems toward the base. Thenbsp;top of some of the branches is enlarged by an agglomeration of small scales,nbsp;whose form, as far as it can be recognized, is figured 11c enlarged. Thesenbsp;are apparently male catkins of the plant. One of the numerous specimensnbsp;covered with branches of this little Conifer is traversed by a small narrownbsp;cone which appears cylindrical, but of which only a few scales are visible.nbsp;These are rhomboidal in outline, pointed at the corners, marked in the middlenbsp;by an oval dot with thin, linear close strim, diverging to the borders; Fig. 8nbsp;enlarged.

I have referred this species to the genus Glyptostrohus on account of the form and mode of divisions of its branches, of the scale-like leaves withoutnbsp;nerves, and of the form and position of the male catkins. But since the publication of my paper on the Cretaceous plants of Nebraska, {loc. cit.,) I havenbsp;received, by the kindness of the author, the Cretaceous flora of Niederschoena,nbsp;containing description and figures of Frenelites reichii, which so well agreenbsp;with the characters of this species that I scarcely doubt their identity.nbsp;The only appreciable ditference is in the leaves, which, as figured 10amp; .by thenbsp;European author, are shorter and marked by a costa. The leaves, however,nbsp;are not figured separately, and may not have been distinct enough to ascertain their exact form. The genus Frenelia, Mirb., is represented by a numbernbsp;of species now inhabiting only New Holland, Tasmania, and New Caledonia.nbsp;From the description of the genus, the branches are terete and the branchletsnbsp;alternately triquetrous, rarely tetraquetrous, and closely articulated; the leavesnbsp;are verticillate by three, rarely by four, adnate, but free in their whole lengthnbsp;at the summit, and in the inferior branches only joined to the stem by theirnbsp;base, somewhat open and linear. This agrees well enough with the description and figures of our fossil species, and even the few scales, recognized fromnbsp;a cone, do not appear to differ from those of a Frenelia, which in old strobilesnbsp;are woody, connate at their base only, smooth, rugose or tuberculate on thenbsp;back, with a bract, mucronate or mucronulate at the top. I have, however,nbsp;been unable as yet to obtain for comparison a branch bearing an old cone ofnbsp;a Frenelia, and I am, therefore, still in doubt about the true reference of thisnbsp;Cretaceous species. It would not be strange to have in these remains thenbsp;representative of another type of Australian Conifers, or of a flora to whichnbsp;some leaves of the Dakota group seem to be related.

In the grayish bituminous clays of the upper Dakota group near Sioux City, which, as remarked formerly, are filled with undeterminable fragments,nbsp;especially of rootlets and branches of Conifers, I have found some rhomboidalnbsp;scales, 2 centimeters wide each way, broadly rounded at the upper border,nbsp;obtuse on the sides, narrowed downward to the spur of the scales, which atnbsp;its base is obtuse and 2 millimeters wide. The whole surface is marked bynbsp;prominent small ribs, curving along the borders and descending into'the spurnbsp;of the scale, becoming of course less curved toward the middle of the scale.nbsp;These costse, transformed into bitumen or amber, are thread-like or cylindrical, leaving a groove upon the stone when dug out of it. Their appearance isnbsp;like the ribbed surface of the scales of Geinitzia formosa, Heer, a new genusnbsp;and species, admirably illustrated by the author in Kreide flora v. Quedlinburg,nbsp;(p. 6, PI. ii. Figs. 4, 6.) As I could obtain but a single scale, preserved wellnbsp;enough to recognize its form, I can only remark on its characters, in order tonbsp;direct the researches to better determined organs of a form which probablynbsp;represents some new and remarkable kind of Conifers.

Leaf oval, oblong, tapering from below the middle to a short thick petiole, abruptly rounded and undulate above, coriaceous; medial nerve narrow, scarcely distinct; lateral veins very close and thin,nbsp;simple, a few more prominent or thicker, all running to the borders.

Phyllocladus subintegrifolius, Lesqx., American Journal of Science and Arts, loc. cit., p. 92.

The leaf is 3| centimeters long from the end of the petiole, which measures ^ centimeter^ 11 millimeters broad at the middle, and abruptlynbsp;obtusely pointed; the lateral veins are very close, more or less indistinct,nbsp;apparently simple, very thin but irregular in thickness, passing to the bordersnbsp;by a slight downward curve in an acute angle of 30�. The borders of thenbsp;leaf are entire, only undulate near the top, and in this differ from the speciesnbsp;of Phyllocladus or Salisburia now known, which are all more or less lobatenbsp;and denticulate. From all the species of Podocarpus, which this leaf resembles by its outline, it differs by its nervation, which is evidently of thenbsp;Phyllocladus type. The lateral veins are apparently rendered indistinct bynbsp;the coriaceous texture and the somewhat wrinkled surface of the leaves, asnbsp;is generally the case in species of this genus.

The species was described from two small imperfect specimens, one representing a small fragment of a leaf. Fig. 14, the other a knot of a branchnbsp;or a root similar to organs of this kind, as they would appear when separatednbsp;from the stem of an Arundo or a Phragmites. This last specimen is a circular, button-like convex scar, 2 centimeters broad, marked at the border ornbsp;outside of the convex center by two parallel rows of verrucose, irregular,nbsp;mostly round, convex papillae; the largest millimeters wide. It is comparable to the scars of Arundo gofperti. Heer, as represented in Flora Tert.nbsp;Helvet., (p. 62, PL xxiii. Figs. 2, 3,) and especially PI. xxii. Fig. 3^ being,nbsp;however, twice as large. Scars of the same form, but not quite as distinct,nbsp;are also seen as branch scars of Phragmites oeningensis in the same work, (PI.nbsp;xxiv. Figs. 1, 2.) The generic relation of those small fragments was contest-able. Recently, Prof. B. F. Mudge has discovered in concretions of thenbsp;Dakota group of Kansas a fine specimen, which, representing the same speciesnbsp;relates it more evidently to Phragmites than to Arundo. It represents, as seennbsp;PI. xxix, Fig. 7, the upper part of a linear lanceolate leaf, 12 centimetersnbsp;long, about 3 centimeters wide at the base of the preserved fragment, graduallynbsp;tapering to an obtuse point, with equidistant, parallel, distinct primary nerves,nbsp;and three or four intermediate thin vinelets. The consistence of the leaf isnbsp;thickish or coriaceous, and the vinelets distinguishable only where the epidermis has been destroyed. This leaf is, in its characters, similar to thenbsp;fragments of leaves represented by Heer, {loc. cit., Figs. 1, 5, 8, of the samenbsp;PL, XXV,) where the characters of Phragmites oeningensis are so finely illustrated. This leaf of ours shows the same form in its upper part, alsonbsp;same kind of nervation, differing only by the narrower space between thenbsp;primary nerves. As this space varies in leaves of the Tertiary species according to their width, and as it is also seen diminishing on the Cretaceousnbsp;leaf in ascending to the point, the difference is unimportant. Specificallynbsp;this new species of Phragmites is separated from the Tertiary one by itsnbsp;coriaceous consistence, rendering the vinelets discernible only under the thicknbsp;epidermis, and by the large size of the verrucose knots.

Leaf coriaceous, entire, nearly round, slightly emargiuato at the point, broader than long, round or truncate at base; veins apparently all from near the base, the outside ones curving parallel to thonbsp;borders, and somewhat branehing; the others parallel to each other, simple, curving in the same waynbsp;in ascending, connected in the upper part by arched nervilles, tho inner ones aerodrome.

The leaf is lacerated in the middle through, from top to base, and therefore the nervation is not satisfactorily ascertained. The upper lateralnbsp;veins appear as branching from the destroyed middle nerve. According tonbsp;the remark of Saporta, this leaf is referable to both the present generanbsp;Dioscorea and Pitsia.

Eays narrow, splitting in laoini� ; veins prominent, parallel; intermediate space concave, marked with indistinct veinlots, parallel to the primary veins.

The fragment shows four rays or laciniee, diverging upwards as if out of the same central point, splitting in ascending, in the same manner as thenbsp;rays of palm leaves in the upper part, and thus enlarging fan-like. Thenbsp;lines or nerves marking these divisions in their length are parallel, narrownbsp;ridges, separated by concave grooves, having the appearance of the folds ornbsp;rays of Sabal leaves reduced to a very narrow proportion, Fig. 12�� enlarged.nbsp;If these fragments represent a species of palm, it is a very diminutive one.nbsp;They cannot be compared to gramen leaves on account of their fan-likenbsp;division. The substance is, if not thick, at least hard, firm, the surface polished and shining like culms of straw. This small fragment seems to indicate the first traces of palms in our Cretaceous measures.

Liquiuambae integeifolium, Lesqx., PI. ii, Fig. 1-3; PI. xxiv. Fig. 2; PI. xxix, Fig. 8.

Leaves of medium size, coriaceous, deeply five-paJmately lobed; divisions ovate-lauceolate obtuse, eutire, separated by obtuse siuuses.

The first description was made from a single leaf. Since then I have found a number of specimens of the same kind, all representing leaves of anbsp;smaller size. They vary from 10 to 16 centimeters broad, from the points of thenbsp;lowest lobes, from 8 to 15 centimeters long, without the petiole. The lobes,nbsp;cut to nearly the middle of the leaves, are equally diverging, the lowest horizontally or at right angle to the middle nerve, and the intermediate at aboutnbsp;the same angle between the lowest and the middle lobe. The lobes are perfectly entire, slightly enlarged in the middle, and ovate-lanceolate, obtuselynbsp;pointed, or, in the smaller leaves, oblong-obtuse. The palmately dividednbsp;primary thick nerves are united a little above the basilar border of the leaves,nbsp;either all at the same point, or the lateral ones parting from the middle nervenbsp;a little above its base, and, as seen in Plate iii. Fig. 2, the lowest are branching too at a distance from the base of the lateral nerve. The characters ofnbsp;the areolation and the divisions of the veins are the same as in our presentnbsp;Liquidambar styracjfiuum, L., and but for its entire borders and the somewhatnbsp;broader and shorter divisions of the fossil leaves, those of PI. ii, at least, wouldnbsp;be referred as identical to our present species. Even the petiole, at the pointnbsp;of union with the leaves, appear bordered like the living species by a folia-ceous appendage, PL ii. Fig. 1. The two small leaves, however, representednbsp;in PL xxiv and xxix, seem by their smooth surface and round obtuse pointnbsp;referable to a variety of this species or related to a different type, that of thenbsp;Acerinm (?) Of the four species of Liquidambar known in our present flora allnbsp;have the divisions of their leaves serrate; of the fossil species, one, Liquidambarnbsp;goepqjerti, Wat., PL foss. du bass, de Paris, (p. 166, tab. xlvii, Fig. 4,) has thenbsp;borders entire, but the leaf merely trilobate ; a second, L. Scarabellianum,nbsp;MassaL, Flor. foss. Senegal, (p. 239, PL xv, xvi, Figs. 7, 11; PI. xx. Fig. 1,nbsp;and PL xxxviii. Fig. 7,) has leaves with acute lobes and sinuses, without analogy with the forms of ours. A third species. Platanus sirii, Ung., Floranbsp;V. Sotzka, (p. 36, PL xxxvi. Fig. 1,) is more closely related to the Cretaceousnbsp;leaves by its general form, but is more deeply lobed, its lobes proportionatelynbsp;narrower. It is, however, of the same type, and, considering its genericnbsp;affinity, the author is uncertain if the leaf should be referred to Liquidambarnbsp;or to Acer. It is also related to L. gracile of the second Tertiary group.nbsp;In this leaf the secondary nervation is apparently totally obsolete. In

ours it is distinct and evidently of the Liquiclambar type. Corda in Reuss. Verstein, PI. li, Fig. 4-5, represents from the Planer Sandstein of Trziblitznbsp;equivalent to the lower Quadersandstein of Bohemia, under the name ofnbsp;Phyllites sp., two fragments of leaves of the same type as ours, or even perhaps of the same species.

Habitat.�Eight miles above Salina Station, Kansas. The first described specimen, PL ii. Fig. 1, was probably discovered by Professor Mudge at thenbsp;same locality. It has been communicated by the Smithsonian Institution.

Leaves round, oval, obtuse, entire, palmately or subpinnately nerved; nervation craspedodrome.

To this genus I refer leaves related by form and nervation to the genus Poqmlus, from which, however, they differ by the generally entire, obtusenbsp;leaves, narrowed to the petiole, abruptly curving to it from a truncate or cordate base, or passing to it by a longer slightly decurring base; and especiallynbsp;by the more distinctly craspedodrome nervation; the lateral nerves and theirnbsp;essential divisions evidently running to the borders. They represent altogether some of the characters pertaining to the genera Populus, Fagus,nbsp;Platanus, and even Acer. Their relation to Populus is so indefinite thatnbsp;Schimper, (Pal. Veget.,) places P. lancastriensis and P. cyclophylla in hisnbsp;doubtful species, while he admits Populites elegans as a true Populus. It isnbsp;therefore advisable to consider all these forms under a peculiar generic name,nbsp;until further researches and perhaps the discovery of the fruits may point outnbsp;their positive relation. Some forms admitted at first into this division arenbsp;now separated from it on account of a more marked relation with other genera.nbsp;The name Populites has been already used by Massalongo in Flor. Senig. fornbsp;the description of a leaf, P. gasparini, which by its form is indeed comparablenbsp;to some of our Cretaceous species, but whose nervation is different, the lateralnbsp;veins and their divisions curving along the borders or evidently camptodrome.

Leaf large, broadly cordate, pointed (?) with entire, slightly undulate borders; primary nerves in five, subpalmately divided.

Populus lancastriensis, Lesqx., American Journal Science and Arts, loc. cit., p. 93.

A large leaf, 12 centimeters broad, 10 centimeters long without the petiole broken 1 centimeter from the base; broadly cordate, apparently pointed, with

entire slightly undulate borders; lowest primary nerves thin, following the borders, the lateral oblique, (50�) parallel, branching; divisions running tonbsp;the borders; nervilles in a right angle to the nerves and their divisions,nbsp;distant and distinct, nearly continuous. The areolation of this species is ofnbsp;the Platanus or Dombeyopsis type. Schimper (Pal. Veget., p. 704) considersnbsp;it as related to this last genus.

Leaves broadly oval or nearly round, narrowed by an abrupt curve to a long slender petiole j borders entire, undulate; nervation pinnate, the lowest secondary veins from above the border of the leaf.

A well-preserved entire leaf of the same thickish, but not coriaceous, substance as the former, 8 centimeters broad, 10 centimeters long, exclusive ofnbsp;the petiole centimeters, round in outline, more enlarged below the middle,nbsp;very obtuse, pinnately nerved; angle of divergence of the veins 40�; areolationnbsp;and divisions of the veins of the same type as in the former species. This leafnbsp;has not the basilar primary nerves remarked in the former, and the lowestnbsp;pair branches opposite from above the base of the middle nerve. Thesenbsp;differences, and the form of the leaf, seiDarate it evidently.

Leaves round, entire or slightly undulate, rounded or truncate to the petiole ; texture rather thin ; nervation pinnate from the hase; lateral veins straight, simple, or the lowest only branching, craspe-dodrome.

Populus cyclophylla, Heer (1), Proceedings of the Academy of Natural Sciences, Philadelphia, 1858, p. 266.�Lesqx., American Journal of Science and Arts, loc. cit, p. 93.

From the short diagnosis given of his species by Professor Heer, I considered this as identical to it. From the observations of the author, however, it is jjrobable that I am mistaken in this supposition. The leaves representednbsp;by many specimens are all nearly round, 6 to 7 centimeters wide each way,nbsp;either abruptly rounded to the petiole or truncate at base, the bordernbsp;slightly inclining downward at the point of contact with the petiole. Thenbsp;nervation is pinnate from the base of the leaves, the lateral veins, five pairs,nbsp;at equal distance, parallel, all simple except the lowest, passing up from thenbsp;medial nerve at an angle of divergence of 40� and reaching the borders without

scarcely any diminution in their thickness; they are joined by perpendiculai distant subcontinuous nervilles forming large areas, with a close, nearly squarenbsp;areolation. I have referred to the same species the leaf of PI. xxiv. Fig. 4,nbsp;with some doubt. The form is the same, as also its thin substance; but itnbsp;hears under the lowest pair of lateral veins a distinct marginal one, and thenbsp;lateral veins are more divided than in the normal form. These differencesnbsp;do not appear marked enough for authorizing a separation.

men of PI. iii comes from this last locality, where I found it with other fragments of the same species.

Leaves lanceolate, taper-pointed, largest at or more generally below the middle, coriaceous; surface polisbed.

The size of these leaves is very variable, from 5 to 12 centimeters long and 1 to 2 centimeters broad, generally lanceolate and gradually tapering tonbsp;the point from a little above the base where they are the largest, and descendnbsp;by a more or less tapering outward curve to a short petiole; some of thenbsp;leaves, however, as seen in Fig. 2 and 4 are wider in the middle, and judgingnbsp;from the last figured leaf, the smallest, the form is sometimes oblong ovalnbsp;and the point blunt. The species is represented by a number of leaves,nbsp;some crowded upon the same specimens and indentifiable, though fragmentarynbsp;they may be, by their thickish texture and polished surface. For this reasonnbsp;I have considered them all representing a single species, though different thenbsp;outlines and size of the leaves may be. From their form, and especially theirnbsp;nervation, which is marked Fig. 3 as distinct as it could be seen, these leavesnbsp;are truly referable to Salix, and merely considering these characters, theynbsp;could not be separated from Salix tenera, A. Br., as figured and described bynbsp;Heer, Flor. Tert. Helv., (p. 32, PI. Ixviii, Fig. 7-13.) The variety in thenbsp;form of the leaves enlarged in the middle or above the base; in their size,nbsp;even in the nervation, is exactly the same.

The remark of Schimper, (in Pal. Veget., vol. ii, p. 663,) that if the relation of some saliciform leaves of the Cretaceous formation is rightly ascertained we have here one of the oldest forms of the Angiosperm dicotyledonous,nbsp;is, with its restriction, applicable to every kind of fossil vegetable remains

whose relation cannot be positively affirmed if the seeds or other essential characteristic organs are not discovered. The number of leaves, however,nbsp;which have to be referred to the same order of the vegetable scale tends tonbsp;confirm the relation of these leaves as it is indicated. The leaves referrednbsp;to the ProteinecB or to an Australian type are mostly, if not all, withoutnbsp;nervation, and therefore of a far more doubtful relation. With us, at least,nbsp;the Eocene formation has scarcely any well recognized species of willows;nbsp;none as yet whose characters are as evident as in the Cretaceous leaves.nbsp;They become, however, more predominant in the Carbon and Evanstonnbsp;groups of the Tertiary, and especially in the Pliocene.

Leaves small, rhombic-obovate in outline, cuneiform from tbe middle downward to tbo petiole, rapidly tapering from above tbe middle to a point, unequally simply toothed in its upper part, undulatenbsp;entire to tbo base; nervation pinnate, craspedodrome.

Betula beatriciana, Lesqx., American Journal of Science and Arts, loc. cit., p. 95.

The species was at first represented by one leaf in three fragmentary specimens. Leaf 6 centimeters long and 3 centimeters broad, rhomboidal,nbsp;cuneiform from the middle to the base, marked above by a small pointednbsp;lobe or tooth on each side, and hence contracted upwards and tapering to anbsp;slightly obtuse point; irregularly and simply toothed or undulate lobed innbsp;the upper part; secondary veins irregularly distant, but parallel, at an acutenbsp;angle of divergence (40�), six to seven pairs, branching near the point, nervillesnbsp;strong, more or less continuous and at a right angle to the veins. Anothernbsp;leaf discovered lately has the same essential characters as the other, being,nbsp;however, smaller with equally distant closer secondary veins. The lowestnbsp;veins in this leaf also are thinner, marginal or parallel to the borders, and joinnbsp;the middle nerve above its base.

This species is, by the form of its leaves and its nervation, comparable to some of the numerous varieties cA Betula nigra, L. The only evident difference is in the simply dentate border of the fossil leaves, which are doublynbsp;serrate in the present species. ' In the Phyllites du Nebraska, Professor Heernbsp;has described under the name oi Betulites denticulata, p. 15, PI. iv, Figs. 5 and

6, two fragments of leaves which have not any relation to this species, and appear, by the enlarged base, to belong to a type related to our Betula luteM,nbsp;Michx, The specimens however are fragmentary, and the affinity of thesenbsp;leaves is uncertain.

Habitat.�Near Beatrice, South Nebraska, Hayden. All the specimens are from the same place.

Leaf tbiokish, round-oval, rounded and narrowed to the slightly attenuated suhoordate base, and above to an obtuse point, entire or marked by a few obscure teeth in the upper part; lateral veinsnbsp;parallel and mostly opposite, the lowest camptodrome, the upper ones entering the teeth; nervillesnbsp;thick, in right angle to the veins.

The leaf is 4 centimeters long, 3^ centimeters broad in the middle, its widest part; round-oval, with borders undulate from above the middlenbsp;downwards, slightly obtusely dentate toward the obtuse point, with sevennbsp;to eight pairs of thick lateral veins, mostly opposite, passing up from thenbsp;middle nerve under a broad angle of divergence of 60�, the lower veinsnbsp;curving along the borders, the superior ones entering the teeth by theirnbsp;point or their divisions. The veins are all at equal distance and parallel,nbsp;except the lowest pair attached to the medial nerve a little above the base ofnbsp;the leaf, and somewhat more open than the others. The nervilles, at rightnbsp;angle to the veins, are strongly inflated at their point of connection to thenbsp;veins, forming by subdivision at right angle, a rough quadrate areolation. Bynbsp;its outline, this leaf resembles the small forms of Alnus viridis, differing however by the borders mostly entire, and by the nervation. By this last character it has some affinity to Alnus gracilis, Ung,, which has sometimes, as innbsp;Fig. 4, PI. XV of Bil. Flora, the borders entire from the middle downwards,nbsp;and the lowest pair of veins camptodrome.

Leaf subcoi�iaceous, small, broadly rhomboidal in outline, with obtuse angles; borders undulate entire, rounded to a thick, short (broken) potiole; nerA^atioii pinnate; veins craspedodrome.

The leaf is 38 millimeters long and about as broad; the secondary veins, seven pairs, at an open angle of divergence 50�, are thick, at least toward thenbsp;base, parallel, alternate, going nearly straight to the borders, mostly simple.

The lower pair follows the border as slightly thinner marginal vinelets. I do not know of any leaf to which this is comparable; by its nervation it seemsnbsp;to have a distant relation to the former; its consistence is as thick, but thenbsp;surface is smooth or polished.

Loaf thick, coriaceous, shining, linear, obtuse, entire; medial nerve thick; secondary veins thin, nearly at a right angle to the medial nerve, curving near and along the borders in marginal festoons,nbsp;anastomosing from the middle or above with intermediate shorter veinlets.

The fragment shows the upper part, centimeters long, of a narrow linear obtuse leaf, only 12 millimeters wide. The secondary veins about atnbsp;right angle, not quite parallel, and also variable in distance, are extremelynbsp;thin, undulating, in passing up to the border which they follow in successivenbsp;curves, anatomosing with the divisions of intermixed shorter vinelets, whichnbsp;come out of the medial nerve under a different angle of divergence, and forming a mixed small quadrate or polygonal areolation. The leaf, by its form andnbsp;nervation too, is somewhat similar to At%dro7neda venulosa, Sap., Efs., Partnbsp;ii, p. 3, PI. iv. Fig. 15, whose details of nervation are admirably figured 15^.nbsp;The direction of the secondary veins to and along the borders, the mode ofnbsp;branching with intermediate shorter veins of a more open angle, the verynbsp;small irregular quadrate or polygonal ai'eolas are still more related to the samenbsp;characters of some species of Myrica, as M. major, Thun, of Japan esj)ecially.nbsp;The leaf is as thick as that of M. venezuelana, Eich of Cuba.

The specimen figured represents a hollow stem 2 centimeters wide, cylindrical, irregularly costate rugose on the outside, marked inside withnbsp;points or small perforations; walls of the tube 3 millimeters thick. Thisnbsp;hollow stem is comparable to a branch of Sainbucus deprived of its pith. Thenbsp;same specimen is furrowed by the impressions of branches crossing at rightnbsp;angles with a number of seeds, which, as seen in Fig. 4 enlarged, are oval-pointed and surrounded by a narrow border. These seeds are similar to thosenbsp;figured as seeds of Myrica in Heer Kride FI. v. Qued., PL iii. Figs. 15-18,nbsp;which are found in the same clay beds with leaves of Myrica schenkiana,nbsp;Heer, (loc. eii, p. 11, PL iii. Fig. 1.)

gives some weight to the reference of the seeds to the genus. The figured specimen, moreover, hears upon its surface fragments of striated scales whichnbsp;compare well with those of a catkin ox Myrica. The agglomeration of seedsnbsp;imbedded into the stone, either flat or oblique or perpendicular, seems bynbsp;itself to indicate their origin as from a crushed catkin.

Leaf subooriaoeous, narrowly oval, equally gradually tapering upward to a point and downward to a short petiole, sharply equally dentate; nervation pinnate, simple, craspedodrome.

Quercus prbnordialis, Lesqx., American Journal of Science and Arts, (1), xlvi, 1868, p. 95.

A well-preserved leaf, narrowly oval lanceolate, broader in the middle, nearly centimeters, gradually tapering upward to a point and narrowingnbsp;downward in the same degree to a short petiole, altogether 11 centimetersnbsp;long; borders equally sharply distantly dentate, with the teeth turned upward, lateral veins close, 14 pairs, deeply marked, parallel, all simple, nearlynbsp;straight to the point of each tooth under an angle of divergence of 40�;nbsp;nervilles about in right angle to the veins, undulate; areolation obsolete.

By its form and its nervation this leaf has its relation marked with .some variety of leaves of Quercus prinoides, Michx., and perhaps still more withnbsp;those of Castanea. This type is represented by a number of species in thenbsp;Tertiary, for example, in Unger�s Flora v. Kumi, as Quercus lonchitis, Figs.nbsp;4 and 6 of PI. v, which have the more likeness to our leaf; in Massal. Flora.nbsp;Senig., as Castanea oinhonii, as illustrated PI. xlii, Fig. 8, amp;c. All these formsnbsp;and a number of other fossil leaves of the same character show always bynbsp;comparison some difference from this Cretaceous species. Debey, in thenbsp;study of the Cretaceous leaves of Belgium, has established a new genus,nbsp;Dryophyllum, containing leaves related to this Prinoid section of Quercus, asnbsp;also to Castanea and Castaneopsis. The nervation is described in Schimper�snbsp;Pal. Veget., IT, p. 613, as subcamptodrome, the veins forhing near the borders,nbsp;a character which is not remarked in this leaf Phyllites geinitzianus, Go^�p.nbsp;from the quader sandstein of Silesia, is closely allied to the Nebraska species.nbsp;Habitat.�Near Decatur, Nebraska, Hayden. It is represented by four,nbsp;specimens, all fragmentary except the one figured as above.

Leaf rbomboidal-ovate, tapering to .a i)oint from above tlio middle, narrowed downward, irregularly dentate above ; nervation pinnate, simxde, craspedodrome.

A mere fragment of a coriaceous or thickish leaf, whose form, as indicated by the preserved part, is rhomboidal or hexagonal, with the sides parallel innbsp;the middle, obliquely tapering to a point, and narrowed to the base. Thenbsp;borders, undulate and entire from the middle downward, are cut above andnbsp;to the point by irregular teeth more or less distant; the secondary or lateralnbsp;veins, 7 pairs, are alternate, diverging only 30�, all simple and simply craspe-dodrome, running to the point of the teeth. No details of areolation are recognizable. This leaf is in appearance, for the form at least, like that. Fig. 5nbsp;of the same plate, which is referred to a Betula. There is, however, a markednbsp;difference in the consistence of the leaves, in the lateral veins thicker andnbsp;simpler in this species, a character not in concordance with the nervation ofnbsp;Betula. The relation, however, of this fragment to Quercus is not positive.

Habitat.�Cass County, Platte River, Nebraska, Hayden. The fragment figured is the only specimen found.

Leaf subooriaceous, oblong-oval, pointed (?), rounded and narrowed to the base; borders undulate; nervation pinnate, camptodrome.

A fragment only of an oblong oval leaf of medium size, 4 centimeters broad, 9 centimeters long, narrowed by an outward curve to the base, (pointnbsp;broken,) with borders deeply undulate, and a pinnate nervation; lateral veinsnbsp;numerous, simple or forking near their point, slightly turning downward tonbsp;the medial nerve, which they join in a broad angle of 50 to 60�. I havenbsp;compared this leaf to some forms of Quercus lyelli, Heer, (Flora of Bovey-Tra-cey, p. 1058.) It is, indeed, like the fragment of leaves figured, PI. Ixiii,nbsp;Figs. 5-6 of this work, not in the form and size of the leaves merely, butnbsp;also in the nervation; in Fig. 5 some of the veins fork in the same way, andnbsp;in Fig. 6 the angle of divergence is the same. This affinity has forced thenbsp;reference of this Cretaceous fragment to Quercus. Some of the lateral veinsnbsp;are shorter, or abruptly disappearing, and this, too, is remarked upon thenbsp;specimens of Q. lyelli, figured by Heer.

Leaf Lroadly oval or nearly round, undulate, obtuse at the top and the base; medial nerve thick, lateral veins thin, mostly opposite, open, curved in passing up to the borders, oamptodronie.

The surface of this leaf is polished; its substance rather membranaceous than coriaceous; it is 4 centimeters long and just as large, apparently round ornbsp;truncate at the point, and rounded to the base in the same way. It is markednbsp;by 6 pairs of thin opposite secondary quot;veins, emerging at an angle of 70� tonbsp;80�, the two lowest pairs more open still, curving and branching near thenbsp;borders, with intermediate thinner and shorter veinlets. The upper part ofnbsp;the leaf is somewhat erased, and the details of areolation undiscernible.nbsp;The relation, therefore, of this species to Quercus is not more definite thannbsp;that of the former.

Leaves ovate, obtuse or truncate at the point, enlarging toward the base, truncate or abruptly curved to a long petiole; borders more or less undulate ; nervation palmate from the base, in three cras-pedodroine divisions.

Populites ovata, Lesqx., American Journal of Science and Arts, (2), xlvi, p. 94.

This species has some affinity with this genus in the form of the leaves and the palmate nervation. In this last character especially, it resembles thenbsp;American C. mississippiensis, and C. tourneforti by the form of the leaves,nbsp;which, however, are crenate in this last species. In Fig. 2, the primarynbsp;nerves, three only, join the top of the petiole, and ascend, branching more ornbsp;less, and under angles of divergence of 30�, to the borders. In the secondnbsp;leaf, Fig. 3, the division of the primary veins is more irregular, the branch onnbsp;the left side being as thick as the medial nerve, and under an angle ofnbsp;divergence of 30�, while the branch of the right side is thin, nearly in a rightnbsp;angle to the medial nerve, appearing like a marginal veinlet, while anothernbsp;branch above it has the normal direction of the primary lateral nerve, but is asnbsp;thin as the lowest marginal vein. This abnormal division of the nerves, asnbsp;also the multiplication of the lateral veins, is apparently casual, and cannotnbsp;indicate a distinction of species for these leaves. Their substance is thenbsp;same�thickish, membranaceous�and also the areolation, which, in its ultimatenbsp;divisions, is small, polygonal, derived from large, square continuous areas likenbsp;that of Platanus, as marked in the enlarged part. The border of the leaves,nbsp;at least, as seen in this same specimen, cut or rounded at the base to nearnbsp;the petiole, turn abruptly down, and are slightly decurrent.

Leaf ovate-oblong, cuneate to the base, short-petioled; borders entire and undulate; medial nervo straight; secondary veins close, numerous, simple, parallel, craspedodrome.

Leaf membranaceous, about 8 centimeters long, (the point is broken,) including a short petiole 4 millimeters long, ovate-oblong, apparently obtuse,nbsp;with borders entire and regularly wavy, especially in the upper part; mediajnbsp;nerve straight and narrow; secondary veins oblique, in an angle of divergence of 40� close to each other, 12 pairs in a length of 6J centimeters, verynbsp;thin, exactly parallel, running to the borders without marking them with anynbsp;denticulation. This last character appears to be the only essential differencenbsp;between this leaf and the one described by Dr. Newberry as F. cretacea^nbsp;which, as he remarks, has the termini of the nerves most prominent, and thenbsp;intervals between them forming shallow sinuses. In our leaf, the secondarynbsp;veins are, on the contrary, effaced to the borders, and they indifferently endnbsp;either at the convex or the concave part of the undulations.

The relation of this leaf to the genus Fagus is undeniable. In comparing it with some leaves of Fagus sylvatica, L., of Europe, it is scarcely possible to point out any difference, except, perhaps, in the more numerousnbsp;secondary veins, and the more acutely wedge-shaped base. The livingnbsp;species also has, in its leaves, the two characters which mark the difference between both the Cretaceous leaves described; one ^with entire wavynbsp;borders, the other with the borders denticulate by the short protractionnbsp;of the point of the veins beyond the borders of the limb. This last eharacternbsp;is more distinct in our Fagus ferruginea. Ait., considered for a long time as anbsp;mere variety of F. sylvatica. We have, therefore, in these two leaves exactnbsp;representatives of the only species of beech now living in the northern regions,nbsp;of both the American and the European continents. Counting eight doubtfulnbsp;species, Schimper describes, in his Pal. Veget., twenty-three species of Fagus,nbsp;all Tertiary except the two mentioned here from the Dakota group, andnbsp;one unsatisfactorily known, from arenaceous concretions of Austria and

Hungary. The Tertiary species are without relation to our Cretaceous leaves; they have dentate or serrate borders, except Fagus duhia, Wat.,

represented by a fragment which does not even appear to belong to a species of Fagus, and F. mcwrophylla, Ung., whose leaves are very large, 18 centi-

meters long, represented by an analogous form in the Miocene of Greenland. Gaudin, in his Contributions, (I, p. 31, PI. vi, Figs. 6-7,) describes Fagusnbsp;sylvatica from the Miocene of Tuscany. His species is represented by twonbsp;leaves, one of which (Fig. 6) would seem a counterpart of ours but for thenbsp;more distant and less numerous secondary veins. The Tertiary leaf has onlynbsp;eight veins when perfect, while, if the point was added to the Cretaceousnbsp;one described here, it would have no less than fifteen.

The presence of a Fagus in the formation of the Dakota group should be taken into account as an indication of the temperature of that epoch,nbsp;especially in searching for relative species of our time.

Habitat.�Decatur, Nebraska, Hayden. A single specimen. The locality of the leaf described by Dr. Newberry is marked Smoky Hills, Kansas.

Leaves hard, subeoriaceous, very entire, petioleu, oblong-lanceolate, pointed, more or less obtusely cuneate to tbe petiole; nervation pinnate; lateral veins close, straight, parallel, numerous.

The leaves, broader below the middle or a little above the base, are more or less abruptly narrowed to the petiole, and gradually tapering to the point;nbsp;the secondary veins, at an angle of divergence of 40�, are straight, numerous,nbsp;all equidistant and parallel, except the lowest pair, which is more oblique andnbsp;parallel to the base; the reticulation is formed by intermediate or tertiarynbsp;veins, which anastomose with nervilles at right angles to the secondary veins,nbsp;forming loose, irregular, quadrate, or pentagonal meshes; medial nerve narrow;nbsp;secondary veins thin.

It is at first difficult to admit that both these leaves are referable to the same species. But in the fossil descriptions and representations of Tertiarynbsp;pinnately-nerved species of Ficus, the secondary veins are often, even uponnbsp;the same leaf, as in Ficus lanceolata, Heer, variable in distance, or close onnbsp;one side and distant on the other. The same difference is recognizablenbsp;in the Cretaceous leaves of Ficus geinitzii, Ett., (Flora v. Niedeeshoena, p. 16,nbsp;PI. ii. Figs. 7, 9�11,) whose forms and nervation have great analogy with thosenbsp;of the Nebraska leaves. Fig. 11 has the secondary veins of the same typenbsp;as those of our Fig. 3, while the broader leaf of Figs. 9 and Q'* enlarged, hasnbsp;a more open nervation, with close veins, and an areolation of the same character as seen in our Fig. 9. There is, however, especially between the fragments represented (Fig. 9) and some species of Rhus�R. metopium, L., for

example�as great an affinity in form and nervation as exists between the Minnesota leaves and those ot Niedershoena, and, therefore, their relation tonbsp;Ficus is uncertain.

Hahitat.�Cretaceous, (Dakota group,) of Minnesota. Collected in numerous fragments by Prof. Ja7nes Hall.

Leaves small, thin, palmately irregularly trilobate; lobes obtuse, short; borders undulate; nervation 3-5 palmate from above the base of the long petioled leaf.

Leaves 6 to 8 centimeters broad in their widest part, not quite as long, round or reniform in outline, enlarged on the side by the diverging obtusenbsp;lobes, abruptly narrowed or undulately truncate at the base, which reachesnbsp;the petiole by a short downward curve; nervation 3-5 peltate; the lateralnbsp;veins at a distance from the basilar border of the leaves, branching; medialnbsp;nerve pinnately divided in its upper part; nervation crespadodrome; nervillesnbsp;irregular, deeply marked, some of them simple and continuous.

In the form of its leaves, and the general character of its nervation, this species is closely related to Anisophyllum semi-alatum, described p. 98. I wasnbsp;even at first inclined to consider all these leaves as representing only onenbsp;species. There is, however, a marked difference : in the texture of thesenbsp;leaves, which is much thinner in this species; in their finer, more delicate nervation ; in their equal divisions in obtuse undulate lobes, amp;c. The platanoidalnbsp;character of these leaves is marked in the branching of the primary veins atnbsp;a distance above the borders, and, therefore, they are not referable to Acer,nbsp;some species of which have leaves of an analogous form.

Habitat.�Beatrice, Gage County, Nebraska, Hayden. Represented by a number of specimens. It may be remarked that all these specimens werenbsp;found at the same locality as those of Anisophyllum. Considering the greatnbsp;affinity of characters, this coincidence tends to indicate identity of species, ornbsp;at least a community of habitat for closely allied, perhaps transient or derivednbsp;forms.

Leaf large, palmately trilobate, with short, scarcely distinct lateral lobes, broadly deltoid, deeply distantly dentate to tbe point, truncate undulate to tbe base; nervation tbree-palmate, platanoidal.

Platanus aceroides ('!), Gopp., var. latior, Lesqx., American Journal of Science

A large subcoriaceous leaf, 11 centimeters broad, 9 to 10 centimeters long, without the petiole, obseurely palmately trilobate, distantly dentate;nbsp;teeth large, sharp-pointed, turned outside; lateral veins at equal distanee,nbsp;parallel.

Though the lobes of this leaf are less marked than in the common form of F. aceroides, Gopp., being merely slightly longer than the teeth andnbsp;of the same form, I am still unable to find any positive charaeter by whichnbsp;this species may be satisfactorily separated from that of Goppert. The border base is undulate, more broadly truncate, not descending as far down alongnbsp;the petiole. But in comparing our figure with that of Heer, (Flor. Tert. Helv.,nbsp;PI. Ixxxviii, Fig. 11,) one sees for the base of the leaves and the distribution of the nervation a perfect similarity. This identity of characters is stillnbsp;more marked between the Cretaceous leaf and P. guillelmce,(ji:o^^., (in Schoss.nbsp;FL, PI. xi. Fig. 1,) and as P. gnillelmce, has been for a long time considerednbsp;by Heer as a variety of P. aceroides�an opinion still sustained by D. Etting-hausen�I do not see the possibility of considering as reason for separationnbsp;the shortness of lateral lobes, which is so generally remarked in P. guillelmce,nbsp;and even in recognized varieties of P. aceroides. I have, however, changednbsp;the name, to follow Heer�s opinion, and substituted one which indicates thisnbsp;species as the original form of a type, which has passed through the Tertiary, andnbsp;which is scarcely modified in our living P. occidentalis.

The fragment represented PI. xxvi. Fig. 2 is evidently of the same species. It is, however, different in its basilar nervation, or rather in thenbsp;lowest branches of the lateral primary nerves, which are not mere marginalnbsp;veinlets, but well-developed divisions, regularly branching. The two figures,nbsp;3 and 4, of Heer�s PI. Ixxxvii, loc. cit., show the same differences ; the largest leaf, Fig. 3, having the lowest secondary veins simple, while in Fig. 4 thenbsp;corresponding veins of the same order are thicker and divided.

Habitat.�Lancaster County, Nebraska, Hayden. In four specimens; the last remarked one is from Salina River, Kansas.

Loaves round or broadly rhomboidal in outline, palmately three-lobed; lobes short, obtuse; borders entire or undulate, oblique or wedge-form toward the petiole, and more or less abruptly decurring alongnbsp;it; petiole short.

Leaves large, 10 to 14 centimeters long and about as wide, coriaceous, smooth, palmately three-lobed; lobes short and obtuse; borders undulatelynbsp;broadly deltoid from the lateral lobes upward, broadly cuneate to the base,nbsp;turning to the petiole, and descending along it about one and a half centimetersnbsp;lower than the primary divisions of the nerves; lateral primary nerves morenbsp;or less oblique, branching; inferior lateral veins either thin, marginal, simple, or,nbsp;as in Fig. 2, thicker, and anastomosing by branches and nervilles, with a marginal undulate vein underneath. This last character is not abnormal; it isnbsp;marked in leaves of our P. occidentalis, when the borders of the leaves arenbsp;entire at the base, and when the lowest basilar veins follow the borders innbsp;curving and in anastomosing with divisions of an upper branch ; it is seennbsp;also in P. aceroides and still more in P. guillehnce.�^The leaf (PL viii, Fig. 4)nbsp;has a somewhat different facies from the two figured, (PI. ix.) Its surface isnbsp;more polished, though its substance is of the same thickness, and the secondarynbsp;veins are less distant from the primary ones. Thisj however, is a differencenbsp;of little moment, for a species whose nervation is so variable, as indicated bynbsp;the two last quoted figures, the one of which (Fig. 1) has a thick secondarynbsp;vein in an abnormal position, under a thick vein of the same order, and thenbsp;other (Fig. 2) has two thick inferior veins under the fork of the primary ones.

Leaf subcoriaceous, round-hexagonal in outline, rounded to the petiole, narrowed in a broad angle to a short point; borders undulate, distantly dentate; nervation pinnate, craspedodrome.

The leaf is 9 centimeters broad, and a little longer, round, somewhat hexagonal ; the upper borders joining in a broad angle to a short point; the sides nearly parallel; and the lower part rounded to the petiole. By its form andnbsp;nervation, the leaf is related to that of Platanus heerii, (PI. viii. Fig. 4,) and alsonbsp;in some degree at least to the leaf described as Sassaffias harlwrianmn, (PLnbsp;xi. Fig. 3.) In some points, indeed, the leaves described in these genera arenbsp;like transitional forms, referable as well to one as to the other.

Leaves 3-5 palmately lobed; lobes nearly equal; borders undulate ; lateral nerves curved outside, forkiug near the base.

This is a remarkable form, of which I have found very few specimens. The more complete ones are figured here. Leaves subcoriaceous, nearly fla-belliform or broadly wedge-form in outline, deeply divided in three or five (?)nbsp;nearly equal lobes, rounded downward, and narrowed by a deep inward curvenbsp;to the petiole; borders entire or undulate; primary veins in three, from abovenbsp;the base, the lateral ones divided by one or two secondary branches as thicknbsp;as the primary nerves, which either curve inward and follow the borders,nbsp;branching and joining the secondary veins above, or curve outside towardnbsp;the point of one or two other lateral lobes of the leaf The primary veinsnbsp;are equally branched on both sides, but the branches vary in number andnbsp;distance, according to the divisions of the leaves. The specimen (Fig. 4)nbsp;is fragmentary, but the expansion of the limb of the leaf and its division innbsp;one or perhaps two lower lobes, in accordance with the direction of the thicknbsp;branches of the primary nerves, is clearly seen on the left side of the leaf Innbsp;comparing the leaf. Figs. 4, 5, of PI. x, with Fig. 4, of PI. viii, the genericnbsp;relation of the forms which they represent is easily seen; but Fig. 3, of PI.nbsp;X, seems to be a deviation from the platanoid type, passing to that of Sassafras, {Araliojjsis,) and, therefore, may not represent the same species. Thenbsp;polished surface of these membranaceous or subcoriaceous leaves and theirnbsp;presence at the same locality induced me to consider them as identical, theynbsp;are related about in the same degree to Platanus or to Sassafras.

Loaves of medium size, thickish, palmately three-lobed, either tapering to a point from the lateral lobes upward or without lobes, and ovate taper-pointed, broadly cuneate to the base, equally dentate;nbsp;secondary veins close, numerous.

Platanus (J) newberryana, Heer, Phyl. du Nebr., p. 16, PL 1, Fig. 4.�Platanus mtoberrii, Lesqx., American Journal of Science and Arts, (2), xlvi, 1868,nbsp;p. 97.

The description of Heer was made from an imperfect specimen, better, however, than the one copied in PL ix. Fig. 2, for it shows under the lateralnbsp;lobes the peculiar kind of dentation which marks the borders to the point.nbsp;Two better specimens have been obtained since; one (PL viii. Fig. 3) represents a palmately three-lobed leaf 12 centimeters long without the petiole,nbsp;10 centimeters wide between the top of the lobes, which are short-pointed.

denticulate, placed a little below the middle of the leaf, with three primary nerves from a little above the base, and 7 to 8 pairs of secondary veins, parallel, close, at an angle of divergence scarcely more than 30�, straight to thenbsp;borders where they enter the teeth with their divisions. The other leaf (PI.nbsp;ix, Fig. 3) is much smaller, not lobate, and has the same kind of nervation,nbsp;except that the primary lateral veins are slightly alternate, not quite as thicknbsp;as the secondary veins above. This, like the other leaf, has its border denticulate, with that peculiar kind of short outward-turned teeth, separated bynbsp;equal obtuse sinuses, remarked in Greviopsis haydenii; Protophyllum mudgii,nbsp;amp;c. The nervation of these leaves, and also the decurrent prolongation ofnbsp;their base below the division of the primary nerves, refer them to Platanus.nbsp;The leaves of young branches of P. occidentalis are often also without lateralnbsp;lobes, or have scarcely distinct lobes, and in that case their nervation appearsnbsp;rather pinnate than palmate.

Habitat.�Beatrice, Gage County, Hayden. Blackbird Hills, Marcou, Capellini. I found it, too, near Decatur, Nebraska.

Leaf small, thick, eularged above the base, rounded downward, narrowed to an obtuse point; nervation 3-palmate.

This small leaf, a little more than 2 centimeters long and nearly as large, may be a diminutive form of P. primoeva or of P. heerii, and even may be referable to another genus. It looks like a leaf stunted by parasitical excrescences.nbsp;It is round from the middle to the base, and broadly deltoid, obtusely pointed,nbsp;undulate or nearly entire. The impression of its surface is deeply furrowednbsp;by the two thick primary lateral nerves, which are slightly alternate, and bothnbsp;like the medial nerve, and the secondary veins are thickened here and therenbsp;by irregular bolsters or expansions. The primary veins alone are branching; the nervilles are thick, continuous, perpendicular to the veins; the basenbsp;appears broken, and, therefore, it is not clear if the leaf is prolonged downwardnbsp;along the petiole.

Habitat.�Dakota group. The specimen had no label. It is mixed with specimens from Lancaster County, Nebraska, and the stone is of the samenbsp;color and consistence.

Leaves thick, coriaceous, elliptical oblong or narrowly lanceolate, obtusely pointed, tapering downward to a short thick petiole; medial nerve thick, half-round; secondary veins alternate, at an acute angle of divergence, camptodrome.

1868, p. 98.

Persea nebrascensis, Lesqx., Transactions of the American Philosophical Soei-ety, vol. xiii, p. 431, PI. xxiii, Figs. 9, 10.

The leaves referred to this species are represented by a number of specimens which mark transitional forms between the large elliptical leaf of PL X, Fig. 1, and the linear lanceolate one of PI. xxviii. Pig. 14. In the memoirs of the Transactions, iloc. cit.,) I had figured, in apposition with this lastnbsp;fragment, the base and petiole of another leaf exactly similar to any of thenbsp;two figures of this report, by its thick vein, thick, short petiole, and secondary nervation, but intermediate to both in form and size. These leaves arenbsp;thick, coriaceous, perfectly entire, the largest 12 centimeters long, includingnbsp;the petiole 2 centimeters; widest in the middle 2J to 4 centimeters broad,nbsp;gradually and equally tapering in a curve up to a slightly obtuse point andnbsp;downward to the thick petiole; the secondary veins alternate, at an acutenbsp;angle of divergence of 30� to 35�, curve near and along the borders, beingnbsp;unequally distant but parallel from the base; the details of areolation, obsoletenbsp;even in the best preserved specimens, are doubtfully indicated by a kind ofnbsp;papillose marking of the surface, which, however, may result from the coarseness of the matrix of the specimens.

If the relation of these leaves to those of some species of Laurus is well marked, as, for example, with Persea speciosa, Heer, of the Miocene of Europe,nbsp;it is not the less evident with some Cretaceous species of Magnolia like M.nbsp;speciosa, Heer, (Mol. FL, PI. 10, Fig. 2.) The narrow leaves of our species arenbsp;comparable also to Myrtophyllum geinitzii of the same, Mol. FL, PL xi. Figs.nbsp;3-4, for their form at least. The presence of a fruit referable to a species ofnbsp;Laurus seems to point out the reference to the same genus of the leavesnbsp;described above.

Laurus macrocarpa, Lesqx., American Journal of Science and Arts, (2), xlvi, 1868, p. 98.

The fruit represents an oval nutlet a little more than 1 centimeter long, 8 millimeters broad, surrounded apparently by a pericarp millimetersnbsp;thick, which seems to have been of a fibrous texture. The nut is marked innbsp;its length by thin, equidistant, scarcely discernible lines or ribs, and undulatelynbsp;wrinkled across; the pericarp being split all around nearly at equal distancenbsp;in fissures enlarged to the point of contact with the nut, and correspondingnbsp;with the wrinkles marked upon its surface. The pedicel, which was easilynbsp;detached from, or scarcely adherent to the fruit, is club-shaped, and markednbsp;upon its horizontal surface, or upon the face in contact with'the fruit, by fournbsp;round, small perforations, which appear like scars of vascular dots. This fruitnbsp;is comparable to that of a number of species of Laurinea: Laurus canariensis,nbsp;Web., as figured by Heer in his Tertiary Flora; Phoebe triplinervis, Gr., anbsp;species of our time, inhabiting Cuba; especially Sassafras officinalis, Nees.,nbsp;and a number of fossil fruits referred to the genus Cinnamomum.

Leaf large, oblong-ovate, lanceolate-pointed; borders entire, nndnlate; nervation pinnate; lower secondary veins distant, curving near and along tbe borders, and ascending to tbe middle of the leaf;nbsp;upper veins more open and shorter.

The texture of this leaf is not very thick; the figured fragment is 14 centimeters long, (the point and the base of the leaf broken,) centimetersnbsp;broad, of an oblong oval form, apparently pointed and gradually narrowed tonbsp;its base; lower secondary veins thinner than the upper ones, following thenbsp;borders, or on a more acute angle of divergence; all camptodrome, more ornbsp;less undulate; medial nerve of medium thickness.

On the description and figure of this leaf in Trans., (loc. cit.f) from which our figure is copied, Schimper remarks, (Pal. Veget., vol. 2, p. 836,) that this leafnbsp;is, indeed, referable to the Lauracece., hut that it is doubtful if it belongs to a Sassafras. The relation by the direction of the veins and the form of the leafnbsp;is with fossil species of Benzoin, described from the Tertiary of Europe, andnbsp;with species of Nectandra and Lindera of our time. Heer, in his remarksnbsp;(in litter.) on the same leaf, is disposed to refer it to Magnolia. The leaf

described as Magnolia tenuifolia (PL xxi, Fig. 1) has a corresponding outline with this one, but the substance of the leaf is thinner, and the secondary veinsnbsp;at a more open angle of divergence. What is said of the relation of this formnbsp;to Quercus benzoin, Lesqx., of Nanaimo, in Trans., {loc. cit.,) is in the samenbsp;degree of uncertainty as before, for the reason that the specimens could notnbsp;be compared.

Leaf large, tliick, coreaoeous, entire, broadly oblong, oval or obovate, obtusely pointed (?) (point broken,) tapering by a curve to the base; nervation pinnate, coarse, very distinct, camptodrome.

Judging from the preserved part of this fine leaf, its length is 15 to 16 centimeters, 10 centimeters wide above the middle; it is of an obovatenbsp;form, perfectly entire, pinnately nerved, with secondary veins thick, alternate,nbsp;distant, separated by some shorter veins in a broader angle of emergence andnbsp;not as thick, which anastomose with nervilles or branches of the principalnbsp;secondary divisions; these are parallel at an angle of 50� to the medial nerve,nbsp;curving near and along the borders, branching in the upper part by obliquenbsp;divisions, or marked in their whole length like the medial nerve by very strongnbsp;nervilles, nearly as thick as the tertiary veins, which, by joining the oppositenbsp;ones and anastomosing, form a large loose reticulation composed of square ornbsp;rectangular meshes.

According to the remarks of Saporta, this leaf compares still better to species of Persea, as, for example, P. gratisima, Gartn., especially the var.nbsp;vulgaris, with obovate leaves, a form extensively represented in the southernnbsp;parts of the North American continent from Cuba to Brazil.

Leaves coriaceous, oblong, linear lanceolate, entire, gradually tapering to the base, and decurrent to a thick costa; nervation pinnate j secondary veins open j areolation loosely distinctly reticulate.

Leaves of a thick consistence, from 10 to at least 16 centimeters long, and from 2 to 4 centimeters wide, entire, linear-lanceolate, tapering from thenbsp;middle upward to a point, and gradually narrowing to the base, where it follows the medial nerve, forming a narrow border before joining the thick short

petiole; secondary veins numerous, parallel from the base, open, at an angle of divergence of 60�, with shorter intermediate veins, which they join from thenbsp;base by curved branches or nervilles, forming a continuous irregular polygo-nous areolation to the borders, where they curve in festoons. This kind ofnbsp;areolation is related to that of Ficus geinitzii, Ett., (Flora v. Nieders, PL ii.nbsp;Figs. 7, 9-11,) but the facies of these leaves, their consistence, amp;c., appear tonbsp;refer them rather to the Laurinece. The numerous fragments of these leaves,nbsp;though, having a common form, may be referable to more than one species,nbsp;some of the leaves being without any traces of veins on their upper surface.

Habitat.�Over the whole of the Dakota group from Minnesota to Southern Kansas, mostly found as yet in fragments.

Leaves 3-palmately, more or less deeply lobed, lobes entire or obscurely dentate; primary nerves forking at a distance above tbe prolonged subdeourrent base of the leaves.

To this genus pertain some leaves formerly referred to Ettinghau-senia.' Some of the forms here described have characters in accordance with those of the leaves of Sassafras officinale, Nees., so widely distributed in the western slope of North America, and the only species left ofnbsp;his genus. It is especially the case for S. mudgii. An objection, however, has been made by Count Saporta against the admitted relation of mostnbsp;of these leaves to the genus Sassafras, especially on account of the dentatenbsp;borders and craspedodrome nervation of some of them. The eminent paleontologist of France considers them as more evidently related to some Arali-acece of Central America of the genus Oreopanax especially. I have been,nbsp;as yet, unable to obtain any specimens of these living plants for comparison,nbsp;and, though admitting the relation as ascertained, I find in comparing between themselves the fossil leaves of the Dakota group which have beennbsp;referred to Sassafras such an intimate coincidence of form and of nervationnbsp;that, admitting one as representative of the genus Sassafras, I am not able tonbsp;find any distinct character to separate the others.

As said before. Sassafras mudgii (PI. xiv. Figs. 3-4) is the form more evidently representing the characters of the leaves of this genus, not only innbsp;comparison with leaves of the living species, but also in regard to the formsnbsp;represented fossil in the Tertiary. The leaf which has been figured especially for this comparison (PI. xxx. Fig. 7) is in its form and nervation intermediate between this S. mudgii dmd. the leaves which have been separated from

this species under the name of S. acutilohum, (Figs. 1-2 of the same plate.) In passing from this form to 8. cretaceum, Newby.', of PI. xii, Fig. 2, no othernbsp;difference is remarked but that of the shorter medial lobe. There is no difference whatever in the nervation, as seen from the comparison of numerous specimens. The two leaves of PL xi, Figs. 1�2, which I have referred to the samenbsp;species, 8. cretaceum, differ by the denticulation of the outside borders, butnbsp;by this only, and a number of specimens of intermediate character have thisnbsp;denticulation either obsolete or distinct, or merely on one side of a leaf, while thenbsp;other border is entire, or, so to say, with intermittent teeth, as marked uponnbsp;Fig. 3, PI. xi, whose upper secondary nerves are either camptodrome curvingnbsp;along undulate or entire borders, or craspedodrome going out to the bordersnbsp;and forming or entering a tooth. Figs. 1-2 of this same plate show the samenbsp;anomaly. The outside borders of Fig. 1 are positively dentate, while thenbsp;middle lobe is entire. In Fig. 2 this middle lobe is marked by two teeth.nbsp;And when we come to the leaves which I have called 8. mirahile, we havenbsp;a nervation mostly craspedodrome, and teeth all around the borders except thenbsp;lower veins, which are still camptodrome. Differences of this kind arenbsp;remarked in the more or less deep divisions of the leaves; in the basilarnbsp;borders decurrent more or less along the petiole, which they join, sometimesnbsp;ta a distance, sometimes quite near the point of union of the primary nerves, asnbsp;seen in PI. xi. Figs. 3-4, and PI. xxvii. Fig. 2. The specimens which represent these vegetable forms are very numerous, and it is only after long comparison of them and a revision of their characters that I have preserved thenbsp;name of 8assafras for the description of these leaves, admitting, however, asnbsp;possible in the future the subdivision of Araliopsis for all the species exceptnbsp;that of niudgii. The same observation may be made for these leaves as fornbsp;other types of the Cretaceous. They may be, and have been considered bynbsp;authors as complex in their simplicity, as uniting some definite charactersnbsp;with some others still in an embryonic state, already slightly apparent, butnbsp;not yet distinct enough to allow a clear line of separation between the original and the derived typical forms.

Leaves proportionally long; lateral primary nerves narrow, at an acute angle of divergence; medial lobe twice as long as the lateral ones ; surface of the leaves polished.

the comparatively longer and narrower leaves, the prolongation of the middle lobe twice as long as the lateral ones, the less oblique direction of the narrownbsp;lateral lobes, and accordingly of the lateral nerves, the acute wedge-form ofnbsp;the base of the leaves decurring along the petiole by a narrow border, and,nbsp;too, by the polished upper surface of the coriaceous leaves. The borders arenbsp;always entire,more or less irregulary undulate; all the secondary veins camp-todrome. The areolation of this species is also less uniformly rectangularnbsp;than in the former ones, and the divisions of the primary veins at a greaternbsp;distance above the base of the leaf By this character this form is more intimately related with the species of Sassafras described from the Miocene ofnbsp;Europe, like S. ferettianum, Mass., which, in some of its leaves, has thenbsp;medial lobe narrowed toward the base in the same way as seen in ournbsp;Fig. 4. In Fig. 7, of PI. xxx, however, the base of the leaf is more enlarged,nbsp;less decurrent to the petiole; the lobes more oblique, a deviation of typenbsp;which seems as a transitional form between this and the following species.

Habitat.�Hills along Salina River, Kansas. The first specimen seen of this species, which is copied in our Fig. 3, was sent from the collections ofnbsp;the Smithsonian Institution, labeled � Presented by Prof. Mudge^ Fromnbsp;the directions of the professor, I visited the locality, and found a number ofnbsp;less perfect impressions of leaves of the same kind. This and the followingnbsp;species are rarely represented in the collections.

Leaves subcoricaceous, of the same consistence as the former species; lateral lobes lanceolate-pointed, diverging nearly at a right angle from the medial nerve; primary nerves more or less disjointed at thenbsp;base.

I considered at first this species as a variety of the former. It is, however, so far different in all its parts, essentially in its general outline, its sharply acute, more diverging lobes, its thin secondary veins uniformly curving alongnbsp;the borders, that it has the same right to be considered as a speeies as thenbsp;other forms described in this paper. As in S. mudgei, the primary nerves arenbsp;comparatively thin; and both surfaces of the leaves, though distinctly markednbsp;by the nervation, are not as rough as in the other species, or more generallynbsp;smooth.

Leaves of medium size, with diverging, slightly obtuse or acutely-pointed lobes, enlarged toward the broad sinuses, broadly wedge-shaped toward the base, deourring to the long petiole; borders entire ornbsp;obscurely dentate.

This species, the most commonly represented in the red shale of the Dakota group, is always easily recognized by the deep, sharply-cut impressions of its leaves, and of the nervation of its under surface. The leaves are generallynbsp;smaller; the lobes sharply-pointed or acuminate, either entire or obscurelynbsp;dentate ; the secondary veins thicker, passing outside to short teeth or curvingnbsp;along the borders, being often craspedodrome and camptodrome in the samenbsp;leaf. As it is evident from the examination of transitional forms, the leaf, (PI.nbsp;xii. Fig. 2,) with its entire borders and slightly obtuse lobes, belongs to thenbsp;same species.

Habitat.�Blackbird Hills, Nebraska ; Smoky Hill Fork, Kansas, Hayden. Fort Harker, amp;c.

Sassafras (Araliopsis) cretaceum var. obtus�m, Lesqx., PI. xii, Fig. 3; PI. xiii, Fig. 1.

This form is recognized from the former by its shorter, especially more obtuse lobes and its very coarse nervation; the primary and secondarynbsp;veins are proportionally much thicker, these especially so from the middlenbsp;downward; the medial nerve, from the forking of the lateral veins to thenbsp;petiole, is twice as thick as in the normal form.

Leaves coriaceous, very variable in size; lobes broad, deep, obtusely dentate on the borders; secondary veins mostly craspedodrome.

The thick leaves of this species vary in size from 8 to 23 centimeters broad between the points of the lobes, and from 9 to 16 centimeters longnbsp;without the petiole, which, as seen upon one of our specimens, is from 6 to 7nbsp;centimeters in length. The three primary nerves separate at a comparativelynbsp;short distance above the decurrent base of the leaves, the lateral ones bearingnbsp;outside in the lower part one or two thin marginal veinlets, which follow thenbsp;borders in successive bows, joining the point of the lowest secondary veins;

these are all simple, entering the points of obtuse teeth, which mark tlic borders of the lobes from their base to the point.

This form differs from all the other species by its large size, its broad, obtusely-dentate borders, and the direction of the secondary veins, all craspe-dodrorne. facies is like that of a Platanus, or of a group referable, perhaps,nbsp;to AraliacecB, like P. nohilis, Newby., P. jatropcefolla, P. hercules, Ung., amp;c.,nbsp;which have representatives in the Miocene of Europe and of America.^

Leaves coriaceous, very thick, broadly round, quadrangular in outline, abruptly narrowed or broadly cuneate to the petiole, and scarcely decurriug at the base; obscurely three-lobed, undulate dentatenbsp;between the acute or obtuse lobes.

This form is like a transient one, and may be considered as in close affinity with S. cretaceum var. obtusum and 8. obtusum. From this, however, itnbsp;differs evidently by the thick smooth coriaceous substance of its leaves; fromnbsp;the former by its scarcely-marked lobes. It is short-petioled, with short obtusenbsp;lobes separated by large undulate sinuses, as in Fig. 4, or with scarcely anynbsp;definite lobes; the lateral primary nerves and the lower secondary veins, too,nbsp;pass up to short teeth, while the upper secondary veins curve near thenbsp;borders, which then are entire or merely undulate, as it is easily seen at thenbsp;upper border of the right side of the leaf, (Fig. 3.) The nervation of this lastnbsp;leaf is coarser than that of Fig. 4; the secondary veins, also, are at a greaternbsp;distance; but the substance of the leaves and their general outline are the same;nbsp;both, too, have been found at the same locality. Fig. 2 of PI. xxvii isnbsp;copied from a specimen sent to me lately (1873) by Dr. Mudge, and foundnbsp;south of Fort Harker, or near Fort Lamed. The leaf, though much smaller,nbsp;has the characters of this species. The disjunction of the primary nerves isnbsp;well marked.

Leaves tbin, flabelliforin, loug-petioled, tbree-obtusely lobed, entire or undulate along the lobes, broadly cuneate or narrowed, and scarcely decurriug to the petiole ; primary nerves forking at a shortnbsp;distance above the border-base of the leaves.

^ Platanus nohilis se�nis to have the peculiar character, remarked in Sassafras leaves, with craspo-dodroiiic secondary veins and dentate borders, or with camptodromo veins and borders entire.

Leaves of small size, three-lobate, with very obtuse, half-round lobes, either perfectly entire or rarely undulately-dentate, narrowed in a broadnbsp;angle of divergence to the petiole, which is slender and very long; secondarynbsp;veins thin, subcraspedodrome, areolation formed of large, irregular quadratenbsp;meshes.

The reference of these leaves to Sassafras is very uncertain. Their appearance is quite different, rather resembling leaves of some of those Am-jjelidecB, Cissus, amp;c., which have a number of representatives in the Eocenenbsp;of the Rocky Mountains, though of a far different type, and to which Heernbsp;refers one of his leaves of the Cretaceous of Moletin, under the generic namenbsp;of Chondrophyllum. These leaves are of a thin texture ; the form and nervation, though analogous, differ also, especially by the apparently craspedodromenbsp;character of the secondary veins, which, though the borders are perfectlynbsp;entire, do not seem to curve as in Sassafras; the slender petiole is also comparatively longer than in any of the leaves of this genus. The leaf (Fig. 2)nbsp;was doubtfully referred to the genus Populites on account of the craspedodrome character of the secondary nerves, and also of the thinness of the leaves.nbsp;It was at the time the only leaf of this type. I have since found many specimens representing the same forms as in Figs. 3-4. They are apparently allnbsp;referable to the same species, the essential difference being only in the narrownbsp;sinuses separating the more undulate lobes of the leaf in Fig. 2. The curvingnbsp;of the broken petiole is evidently casual. The last specimen comes, however,nbsp;from a different locality,-and the identity of these leaves may be ascertainednbsp;only by the discovery of intermediate forms.

Habitat.�Lancaster County, Nebraska, Hayden, the specimen, Fig. 2 ; all the other specimens from Salina Valley.

Leaf thickish, broadly obovate, emarginate at tbe rounded top, narrowed to a thick petiole, anorm-ally tri-palmately nerved; lateral veins at a distance above the borders, disjointed.

By its general appearance, its thick, primary nerves, the narrowing of the border to the base, this leaf seems refei'able to this genus. Even innbsp;considering the primary nervation, we may recognize in the two lowest lateral

veins, though disjointed and distant as they are at the base, two primary nerves forcing the distribution of the limb in two broad, round lobes, apparently folded upon another along the upper part of the middle nerve. Thenbsp;secondary nervation is comparable to that of Sassafras mculapi, Heer, (Flor.nbsp;Tert., ii, p. 82, PI. xc. Fig. 13.) The lateral nerves are irregularly branchingnbsp;outside, and their divisions, in the direction of the borders, are effaced in thenbsp;reticulation before reaching them; the reticulation is composed of very small,nbsp;nearly round or polygonal meshes like those of a Benzoin. This leaf therefore, though positively referable to some Laurinece, is doubtfully so to Sassafras. The distance between the base of the primary nerves, which, normallynbsp;placed, should be opposite, is observable not only in species of Sassafras, asnbsp;in our Fig. 2 of PI. xxvii, but in Cinnamomum, amp;c. Unger, in his Fossil Floranbsp;of Sotzka, (PL xvi. Figs. 5, 7,) has two leaves of C. lanceolatum with the samenbsp;disjunction.

Habitat.�Fort Harker, specimen No. 6434, in the cabinet of the Smithsonian Institution.

Leaves thick, coriaceous, polished on the upper surface, elliptical or ohlong-lanceolate, pointed, narrowed by a curve to the short petiole, entire and slightly undulate, triple-nerved; medial nerve thick; lateral veins opposite, a little above the base, ascending along the borders as high up as the lower secondary veins, which they join by ramifications.

The species is represented by two specimens, one (Fig. 2) representing a leaf narrowly elliptical, acuminate or lanceolate pointed, narrowed by anbsp;curve to the base, (petiole broken,) 5 centimeters long, 17 millimeters broad,nbsp;with a thick medial nerve, and the lateral veins branching and forming alongnbsp;the borders a series of festoons, as in Heer, (foe. ctif., PI. xci. Figs. ,12,18.) Thisnbsp;leaf shows its upper surface and its distinct areolation in small, round areolae,nbsp;as exemplified in this last, (Fig. 18.) The second leaf (Fig. 3) is broken fromnbsp;above the middle, but represents the same characters as the former. It isnbsp;merely broader, with the lateral veins descending lower and nearer to thenbsp;base; comparable for its form to Heer, {loc. cit., PI. xcii. Fig. 5a.) I amnbsp;unable to find any character by which these two leaves could be separatednbsp;from the Miocene species, and consider them as identical.

Leaf thickish, subcoriaoeous, entire, ovate, taper-pointed, rounded downward, three-nerved from the base; lateral veins ascending to above the middle, branching outside.

Cinnamomum heerii, Lesqx., Transactions of the American Philosophical Society, vol. xiii, p. 431, PI. xxiii, Fig. 12.

Our figure is a copy of this last, for, to my regret, and though I carefully searched for specimens representing a leaf like this, I found nothing in thenbsp;Dakota group comparable to it. I have, therefore, nothing to add to mynbsp;former remarks. It is not possible to know, on account of the deformation ofnbsp;the specimen by grinding it round from the middle to the base, if the borders are rounded or narrowed, and if, as in the Cinnamomum leaves, theynbsp;descend lower than the base of the primary nerves. If it is the case, thenbsp;species would be related very closely indeed to C. mississipiense, Lesqx., ofnbsp;the same paper, (p. 418, PI. xix. Fig. 2,) a species abundantly found in tbenbsp;Eocene of the Rocky Mountains and of the Mississippi. The same uncertainty concerning its relation exists for the leaf of Vancouver, from which thenbsp;present species was named, (American Journal of Science and Arts, vol. xxvii,nbsp;p. 361.) The identity of both leaves is, therefore, uncertain.

Leaf elliptical, gradually curving to an ohtuse point, narrowed in about the same degree to its base, entire; medial nerve thick, secondary veins opposite.

This leaf preserved entire, except the petiole, is a little more than 4J centimeters long, I J centimeters broad, narrowly ovate-pointed, with fournbsp;pairs of opposite lateral veins on an acute angle of divergence 30� to 40�,nbsp;branching in the upper part, camptodrome, united together by thick nervilles.nbsp;The lower pair joins the middle nerve a little above the base of the leaf, andnbsp;follows up nearly parallel to the borders, anastomosing by its ramificationsnbsp;with those of the veins above. The substance is thickish or subcoriaceous;nbsp;the surface rough by the coarse nervation.

This form is comparable to Oreodaphne heerii^ Gaud., (Contributions, amp;c., 1st Mem., p. 35, PI. x. Figs. 4-9, and PI. xi. Figs. 1-7.) The leaf is muchnbsp;smaller, but except this there is not great difference of form and nervation.nbsp;Even the small inflation, like bulbs, seen in the axils of the veins of the Miocene species, are also apparent, though not very distinct, in the Cretaceous leaf.

In the description of the first species referred to this genus in T?hyllites du Nebraska, the celebrated author remarks, �I have united, under the namenbsp;of Proteoides, some leaves from Big Sioux River, near Sioux City, which Inbsp;consider as referable to the family of the Proteacece, but which are in such anbsp;poor state of preservation that their precise determination is not j)ossible.nbsp;They are of great interest as the only representatives, but not as yet perfectlynbsp;recognized, of a family represented in abundance in the Upper Cretaceous ofnbsp;Aix-Ia-Chapelle.�� As far, at least, as a comparison can be made with thenbsp;incomplete fragments figured by Heer, our leaves, representing the speciesnbsp;described in the Phyllites and far better preserved, seems to confirm thenbsp;statement of the celebrated author. The relation, however, is still uncertain, based, as it is, merely on the comparison of the forms of leaves, whosenbsp;nervation is mostly undiscernible.

Le.ives ovato-lancGolate near the base, gradually tapering upward to a long, acute, scythe-shaped iroint, entire, smooth, and coriaceous; medial nerve narrow ;, secondary veins obsolete, few, ascendingnbsp;under a very acute angle from the medial nerve and following the borders.

Proteoides daphnogenoides, Heer, Phyllites du Nebraska, p. 17, PI. iv. Figs. 9, 10 ; Lesqx., American Journal of Science and Arts, loc. cit.,nbsp;p. 99.

The best preserved specimen shows an entire leaf, measuring nearly twenty centimeters in length, and three centimeters broad in its widestnbsp;part, a little above the base; the other leaf, also preserved nearly entire,nbsp;is about thirteen centimeters long and proportionally broad, enlarged likenbsp;the other above the base, tapering downward by a curve to a short petiole,nbsp;and more gradually tapering upward to a long point. The secondary veins,nbsp;which are extremely thin, are not at all marked in the large leaf, and arenbsp;distinguished upon the smaller leaf with some difficulty. Heer describesnbsp;his species as leaves coriaceous, narrowed to the base, entire, with anbsp;strong medial nerve, and aerodrome secondary veins nearly parallel to thenbsp;borders. The medial nerve of these leaves is deeply impressed into the stonenbsp;but not thick; and though the secondary veins ascend nearly parallel to thenbsp;borders, they do not appear aerodrome. Though the figures of this speciesnbsp;in the Phyllites show a larger leaf than the fragments of the two others thesenbsp;fragments are too incomplete for positively ascertaining identity.

Leaves coriaceous, linear-lanceolate, narrowed to the base, and gradually tapering upward to a slightly scythe-shaped point; borders undulate; medial nerve broader; secondary veins invisible.

Proteoides acuta, Heer, Phyllites, p. 17, PI. iv, Figs. 7-8; Lesqx., American Journal of Science and Arts, loc. cit., p. 99; Transactions of the Americannbsp;Philosophical Society, vol. xiii, p. 431, PI. xxiii. Figs. 5-7.

The fragments figured by the author indicate much smaller leaves than ours; they do not show the undulation of the borders, as remarked upon thenbsp;numerous specimens which I have examined ; the only character which indicates the identity of these leaves with those of Heer is the total absence ofnbsp;secondary veins. These leaves appear about of the same size as those of thenbsp;former species, but somewhat narrower toward the base ; their surface is notnbsp;polished; the medial nerve is thicker, and the borders undulate. The lowernbsp;part of the leaf (Fig. 5 in Transactions) is somewhat decurrent to thenbsp;enlarged base of the medial nerve, as it is generally in a sessile leaf; the samenbsp;character is remarked in our PI. xv. Fig. 3 ; the fragment, (Fig. 13 of PI.nbsp;xxviii,) like that represented, (Fig. 7 of the Proceedings,) indicates the sizenbsp;of the leaves of this species as being as large as in the former, or from twonbsp;to three and a half centimeters wide.

Leaf coriaceous, small, enlarged above the base, linear-lanceolate, flexuous; borders entire; medial nerve thick; secondary veins alternate, thin, aerodrome, ascending nearly parallel to the borders, andnbsp;curving slightly inward.

Proteoides grevilleceformis, Heer, Phillites, p. 17, PI. iv. Fig. 11 ; Lesqx., Transactions of the American Philosophical Society, loc. cit., p. 432, PI.nbsp;xxiii, Fig. 8.

The same uncertainty exists in regard to the identity of the species described here with that of Heer, on account of the too fragmentary specimen represented in his Fig. 11. Our leaf is enlarged above the base stillnbsp;more proportionally to the size than the leaves of P. acuta; the nervation,nbsp;however, is as indicated by Heer. From the former species, it differs by itsnbsp;very entire, not undulate border, and by the secondary veins more distinctnbsp;than in its two congeners. The point of the specimen is broken; the uppernbsp;part of the leaf, however, appears very gradually narrowing upward in thenbsp;same way as in P. acuta, first curved to one side and then to the other, or

doubly scythe-shaped; the medial nerve is as thick as in the former species, a character which also separates it from P. acuta.

Leaf coriaceous, oblong, narrow, gradually tapering downward, and decurrent to the broad, medial nerve; borders slightly reflexed; nervation pinnate; lateral veins close, at an acute angle of divergence.

The specimen represents only the lower half of a thick, coriaceous, smooth, entire, linear-lanceolate or narrowly-oblong leaf, which is gradually narrowednbsp;downward, the bordei�s slightly decurring along the enlarged medial nerve.nbsp;The preserved part is about 4 centimeters long and centimeters wide;nbsp;the medial nerve at base, with a narrow wing, is 3 millimeters broad; the lateral veins, three pairs, in an angle of divergence of 20�, ascend to and alongnbsp;the borders, and appear to curve inward and join the upper ones by thinnbsp;ramifications.

The fragment represents, apparently, the lower surface of the leaf, which is smooth, and does not expose any details of areolation; the leaf is borderednbsp;by a narrow linear groove, as if the borders were slightly reflexed. Thenbsp;leaves of some Proteinece, however, have a marginal groove of this kindnbsp;marked upon the upper surface along the borders.

The relation of this leaf is uncertain. By its form and nervation, it is comparable to the leaf of Embothi-ium salignwn, represented in Heer�s Flor.nbsp;Tert. Helv., (PI. xcvii. Fig. 35.) In the fossil leaves, the veins are closer andnbsp;more numerous. This fragment also resembles Andromeda Parlatorii, Pleer,nbsp;Phyll., p. 18, PL i. Fig. 5, differing especially by more oblique and morenbsp;numerous secondary veins.

Professor Heer, in the Phyllites, has described, as indicated above, two fragments of a peltate, triple-nerved leaf, with borders crenate-dentate, of which Inbsp;have seen one specimen only, which is figured in this report by the permissionnbsp;of the Museum of Comparative Zoology of Cambridge, to which it belongs, fromnbsp;the collection of Prof. Marcou. This specimen agrees fully with the description and figures of the author. The leaf is smaller, however, 4 centimetersnbsp;long, from the point of attachment of the petiole, which is marked by a cavitynbsp;enlarged on both sides, and placed 1 centimeter above the border-base of

the leaf; this is nearly as wide as it is long, 5 centimeters broad, nearly round; obtusely-dentate, or equally crenate all around ; the nervation is rathernbsp;5-nerved than triple-nerved, two somewhat smaller nerves emerging fromnbsp;the corner of the point of attachment of the petiole, and diverging at rightnbsp;angle to the middle nerve. One only of these lateral nerves is marked innbsp;Heer�s Fig. 1, probably on account of the laceration of the leaf on one side.

Though I have closely examined the locality where Messrs. Marcou and Capellini have found their specimens, I have been unable to discover anynbsp;trace of this species, as also of the fragment of leaf described by Heer (Fig.nbsp;3 of the same plate) under the name of Cissites insignis. Both are fromnbsp;Tekamah, Nebraska.

Loaf lanceolate, narrowed to the base and decurring along the petiole hy a narrow border, entire ; medial nerve thick ; secondary veins at an acute angle of divergence, parallel, camptodrome.

Andromeda parlatorii, Heer, PhilL, p. 18, PI. i. Fig. 5 ; Lesqx., Transactions of the American Philosophical Society, vol. xiii, p. 432, PI. xxiii. Fig. 11.nbsp;Prunus (^) parlatori, Lesqx., American Journal of Science and Arts, loc. cit.^

p. 102.

The specimen referred to this species in the Transactions is somewhat more complete than the one figured by Heer; it has the base of the leaf,nbsp;apparently an enlarged petiole, to which the leaf is decurring in a narrownbsp;border. This leaf appears thickish or subcoriaceous; the upper end of thenbsp;secondary veins are not distinct, though in the lower part they are thickernbsp;than figured by Heer; its areolation is undistinguishable.

I refer to this species, from the revision of the specimens, the two leaves, (PL xxiii. Figs. 6-7,) which I have described in the Journal, as markednbsp;above, under the name of Prunus {AndromedaV) parlatori. The referencenbsp;of these leaves, one of which is whole, oblong, gradually tapering upward tonbsp;an obtuse point, was doubtfully indicated by the presence, in the shale, ofnbsp;two nutlets, resembling the fruit of Prunus. The nervation of these leavesnbsp;as marked (Fig. 6) is more positively that of some species of Andromeda.nbsp;I have, however, preserved the name of Prunus for the description of thenbsp;fruits.

Leaf coriaceous, narrowly oral, obtusely acuminate; borders entire ; norration iiiunate, camptodrome.

Leaf of medium size, 3^ centimeters wide, about 9 centimeters long, narrowly oval, contracted to a short, obtuse acumen; borders perfectly entire;nbsp;lateral veins deeply marked, curving to and along the borders, simple; surface smooth, marked by continuous nervilles, perpendicular to, and anastomosing in the upper part with the veins.

The reference of this leaf to Quercus was indicated by its specific name as very doubtful. Its form is much like that of Diospyros lancifolia, Lesqx.,nbsp;as figured by Heer in his Vancouver Flora, (PI. i. Figs. 10-12, and PI. ii.nbsp;Figs. 1-2.) This leaf is, however, obtusely acuminate; its substance isnbsp;thicker, and the veins are at a more equal and greater distance, curvingnbsp;nearer to the borders. Diospyros primmva, Heer, (Phyll. du Neb., p. 19, PI. i,nbsp;Figs. 6-7,) difiers essentially from this leaf by its undulate, secondary thinnernbsp;veins, separated by shorter tertiary veins, which divide the nervilles. Thenbsp;type is different. The reference of our leaf is still uncertain ; it may represent a kind of Laurus (?).

Habitat.�Ten miles below Lancaster, Salt Creek, Nebraska, Hayden; two fragments.

Leaf subooriaceous, entire, nearly round, pinnately-veined; secondary veins parallel, camptodrome.

The species is represented by a fragment of a leaf of which the lower part is destroyed. It is about centimeters long, 7 centimeters wide,nbsp;with a narrow middle nerve and six to seven pairs of lateral veins, on annbsp;angle of divergence of 50� to 60�, branching and curving at a distance fromnbsp;the borders, and forming, by their divisions, a double festoon along them.nbsp;The veins are joined by coarse or thick fibrillse nearly at a right angle tonbsp;them, but disconnected, and forming, by divisions and subdivisions, a netting of very small square or polygonal areolee. The secondary veins and thenbsp;nervilles also are deep, and mark the surface of the leaf with wrinkles andnbsp;undulations. This fine leaf has some relation of form and nervation withnbsp;Diospyros styracifolia, Sap., a leaf of the Lower Eocene of Montpellier, anbsp;sketch of which has been obligingly communicated to me by the author. Inbsp;do not know of any other fossil species to which this leaf could be comiiarednbsp;but, by its form, to the leaf of Juglans (?) deheyana, (PI. xxiii. Fig. 2, of thisnbsp;12 L

report;) far different, however, by its nervation. In regard to living species, its affinity is with D. coceolohcEfolia, Mart., of Brazil.

Habitat.-^Wextern Kansas, found in concretions by Professor Muclge. These concretions appear rich in leaves, which have not been preserved, or,nbsp;at least, have not been found yet in the arenaceous shale of the group.

Leaf mernbrauaceous, broadly oval, entire, emarginate, rounded downward to a long, slender petiole, penninerve.

Leguminosites marcouanus, Heer, Dana�s Manual of Greology, Ed. II, p. 459, Fig. 827.

Leaf 5 centimeters long from the top of the slender 2|-centimeter-long petiole, more than centimeters broad, very entire; with seven pairs ofnbsp;secondary veins, parallel, on a broad angle of divergence of 60� to 70�, passingnbsp;up to near the borders, where a few of them branch once, and all becomenbsp;effaced. These veins are mostly opposite, the lower pair joining the middlenbsp;nerve a little above the borders; this, with the second and third pairs, arenbsp;closer to each other, 4 millimeters in distance, while the upper pairs arenbsp;more distant, 6 to 9 millimeters, all straight or slightly curved. The notch isnbsp;marked by two straight lines, which, however, are smooth like a continuationnbsp;of the borders, and not as resulting from erosion. The leaf is so very similarnbsp;in form, size, and nervation, also, to those of our present Rhus cotinus, whichnbsp;also are sometimes notched, that a relation to this last genus could be supposed. The absence of any trace of areolation prevents a close comparison.nbsp;The notch is, however, deeper and more marked than in any of the leaves ofnbsp;R. cotinus. This leaf is evidently identical to that figured in Dana�s Manual,nbsp;{loc. cit.) The long, slender petiole of this leaf prevents its reference tonbsp;Leguminosites.

Habitat.�Minnesota, James Hall; two fragments, one with the petiole; Nebraska, Marcou; a fragment without petiole.

Leaves membranaceous, three-nerved from above the base, five-lobed by the forking of the primary nerves; lobes oblong, somewhat narrowed downward, entire or undulate; base of the leaf cuneiform.

isb, subcoriaceous texture, narrowed cuneiform at base, apparently petioled, jjalmately tbree-nerved and three-lobed; primary lobes deep to near tbe pointnbsp;of union of the nerves; lateral ones cut in two much shorter divisions, ornbsp;bilobate by the forking of the lateral primary nerves, which branch at a shortnbsp;distance above their base; sinuses narrow, but obtuse. The upper part ofnbsp;the lobes is destroyed. As far as can be seen from the specimen figured, thenbsp;leaf is five-lobed, with lobes diverging, like the nerves and their divisions, atnbsp;an acute angle of 30� to 35�. The lobes appear all entire. There is onlynbsp;a trace of undulation on the upper part of the right lateral lobe, just near thenbsp;broken line of the leaf. Prof Heer, in Keide Flora v. Moletin, (p. 18, PI. viii.nbsp;Fig. 3,) has described Aralia formosa, a three-lobate leaf with crenate lobes,nbsp;which is closely related to our species. It differs merely by having threenbsp;divisions only, and the borders obtusely crenate in the upper part of the lobes.nbsp;The Kansas leaf has, however, the upper half of the lobes destroyed ; and, fromnbsp;a kind of undulation marked along the upper part of the outside borders, itnbsp;would seem as if the lobes, too, had been undulate dentate in their upper part.nbsp;This leaf, also, is much larger than that of Heer; and it may be that, as it isnbsp;the case in some species of Aralia.! the smaller leaves are merely trilobate,nbsp;and the large ones darted in five or more lobes by subdivision. As identicalnbsp;between the European species and ours, we have the following characters:nbsp;tripalmate basilar nervation; subcoriaceous substance of the leaves; the samenbsp;wedge-form base of the leaves; and the borders entire toward the base.

LeJives coriaceous, entire, oval, Uroadly obtuse, narrowed to the base, pinnately nerved; medial nerve thick; secondary veins alternate, irregular in distance, more or less numerous j nervation mixed.

In comparing the nervation and areolation of these leaves with our living Hedera helix, L., their reference to this genus is obvious. The smaller leavesnbsp;show apparently the upper side; the other, (of PI. xxv,) the lower, with thenbsp;veins and their divisions more marked, and the medial nerve increasing innbsp;thickness toward the base by the connection of the secondary veins. Thenbsp;leaves, whose petiole is broken, are thick, from to centimeters long,nbsp;3^ to 4J centimeters wide, oval, round-obtuse, narrowed by a curve a littlenbsp;more on one side than on the other, or slightly unequilateral. The secondarynbsp;veins are either curved near and along the borders or passing up and entering them; the areolation is in large, irregular meshes, by nervilles anastomosing with divisions of the secondary veins, in various angles of divergence.

The angle of divergence of the secondary veins is also variable. Leaves of H. helix, L., the European ivy, have been found fossil in the Tertiary of Italy.nbsp;Gaudin (in Contributions, etc., Ill, p. 17, PI. i. Figs. 21-24) describes, undernbsp;this name, leaves closely related by form and nervation to those of the Dakotanbsp;group.

Habitat.�Near Decatur, Nebraska. The specimen of PL xxiv. Fig. 4, is from Kansas, Mudge.

Leaf large, oblong, rounded upward to an obtuse point(?), (broken,) narrowed in a curve to a short, slender petiole; medial nerve straight, narrow; lateral veins alternate, on a broad angle of divergence,nbsp;slender, undulate, deflexed near their point of insertion to the medial nerve.

The upper part of this leaf is destroyed; it is a large leaf of thin texture, about 17 centimeters long, 7 centimeters broad, oblong oval, entire or undulate, on the borders, apparently rounded upward to an obtuse point, gradually curving to the petiole, which, like the medial nerve, is rather slender, atnbsp;least for a leaf of this size. The secondary veins mostly opposite, irregularnbsp;in distance, or obliterate here and there, are very thin, on a broad anglenbsp;of divergence of 60�, undulating to the borders, where they curve, and whichnbsp;they appear to follow.

The relation of this leaf with that referred to Persea leconteana has been remarked upon in describing this last species.

Leaves coriaceous, ovate-oblong or elliptical, entire, tapering to the petiole; secondary veins numerous, parallel, camptodrome, at an acute angle of divergence.

Magnolia alternans, Fleer, Phyllites, p. 20, PL iii. Figs. 2-4; PL iv. Figs. 1-2.�Lesqx., American Journal of Science and Arts, loc. cit., p. 100.

The leaf figured in this memoir is not as perfect as those which Professor Heer had for his description of this species. Our figure is comparable in size, form, and nervation to that of PI. iii, Fig. 3, of the Phyllites, which hasnbsp;the base of a leaf with a short, slender petiole, while the upper part and thenbsp;base of ours is broken. In both these leaves, as also in the fragment represented, (PL iv, Fig. 1, of the same memoir,) the secondary veins appearnbsp;intermixed with shoiFer tertiary ones. This character, like the form of the

leaf, identifies ours with Hcer�s species. I have very rarely recognized it among the specimens received for examination.

Habitat.�Fort Harker, Kansas; a single specimen, No. 6433, from the collections of the Smithsonian Institution.

These leaves are figured from drawings communicated to Professor Heer by Dr. Hayden. They are small, 4J centimeters long, truncate or scarcelynbsp;emarginate at the top, with round, very obtuse terminal lobes, and slightlynbsp;less obtuse basilar ones. The nervation is of the type of Liriodendron. Inbsp;have seen some fragments referable to this species in Dr. Hayden�s and Professor Hall�s specimens; but I have not been able to discover any myself.nbsp;All these fragments come from north Nebraska and from Minnesota.

Dr. Newberry has in his Extinct Flora a species, Liriodendron primcevmn, which, according to the description, is distinct from this one by its large sizenbsp;and the lobes more broadly rounded. It is described from specimens foundnbsp;in Blackbird Hill, North Nebraska, by Hayden.

Leaf large, tliree-lobate; upper lobe elongated, deeply emarginate-lobed; secondary veins tbin, par.allel.

Liriodendron intermedium, Lesqx., American Journal of Science and Arts, loc. cit., p. 99.

Though the specimen represents a fragment, the upper part of a leaf, it is sufficient to show the relation of this leaf to the genus Liriodendron. Thenbsp;leaf in its integrity is at least 14 centimeters long; the basilar lobesnbsp;appear to have been much enlarged, and abruptly so, and the leaf contractednbsp;or narrowed between the lower and upper lobes, which are obovate-obtuse,nbsp;4 centimeters long, and separated by a deep, slightly obtuse sinus. Thisnbsp;fragment shows a thickish, somewhat coriaceous leaf.

A mere fragment, still more incomplete than the former, representing the half of the upper lobe of a species of this genus. From the preservednbsp;part, the whole upper lobe measured 17 centimeters wide, while that of thenbsp;former species measures only centimeters. The secondary veins of thisnbsp;magnificent leaf are very thick, at least comparatively to those of the formernbsp;species, but not thicker than they are in large leaves of our L. tulipifera, L.,

a species from which all our Cretaceous forms difier bj their round-obtuse lobes. The same characters separate them from the Tertiary species ofnbsp;Europe, L. procacini and its numerous varieties, whicli all are more or lessnbsp;acutely-lobed.

Habitat.�Near Fort Harker, Kansas; No. 6432 of the collection of the Smithsonian Institution.

Leaves large, coriaceous or subcoriaceous, broadly deltoid, more or less distinctly three-lobed, with obtuse divisions, and borders entire or undulate;nbsp;nervation palmately 3-5 nerved, from a peltate or subpeltate, truncatenbsp;or subcordate base; primary veins crasjaedodrorae, their points joining thenbsp;borders of the lobes, but their divisions following along them by a series ofnbsp;curves upon each others, or of multiple festoons, as seen in the leaves of thenbsp;present Menispermum canadense especially. The divergence from this lastnbsp;type is marked in one species only, whose nervation agrees with that of Menispermum (Cocculus) carolinum.^ amp;c. The leaves referred to this genus havenbsp;been described formerly as Amr or Acerites, Dombeyopsis, even Populites.nbsp;Their essential characters seem to refer them all to this section.

Leaves large, coriaceous, broadly deltoid or nearly round, obtuse in outline, peltate, 3-5-nerved, deeply undulate.

These leaves are thick, variable in size, the largest 20 centimeters long, 15 centimeters wide, reniform-deltoid in outline, obtuse, peltate, enlarged, and truncate at base, obscurely three-lobate, with borders deeplynbsp;undulate; five-nerved; primary nerves under various degrees of divergence,nbsp;much branched, subcraspedodrome, their points reaching the borders withnbsp;camptodrome divisions anastomosing in bows along the borders and alongnbsp;the veins, with two to four veinlets under the primary veins, around thenbsp;point of attachment of the petiole. The leaf (PI. xxv. Fig. 1) is the betternbsp;preserved one of this species. I have, however, seen fragments indicatingnbsp;leaves of a larger size. In this the three-lobate form is more marked thannbsp;in the other figured specimens. It is evident that the leaf (PI. xxvi. Fig. 3)nbsp;belongs to the same species. In PI. xxv. Fig. 2, the base of the leaf isnbsp;destroyed ; but the union of the primary nerves and of the basilar veinsnbsp;is clearly seen as being above the borders. The middle nerve is notnbsp;branching; at least, no trace of secondary veins could be seen on the spec-

imens. It will be remarked, however, that the first lateral vein of the left side has no divisions whatever, while that of the other side has three strongnbsp;branches. The absence of the medial secondary veins may, therefore, benbsp;casual, or the veins may have been erased from the impression of the leaves.nbsp;As it is seen from the divisions of the primary nerves, and of their branches,nbsp;in PI. xxvi. Fig. 3, the direction of the nerves and their ramifications are verynbsp;irregular.

Habitat.�Bluffs of Salina River, eight miles above its mouth. Menispeemites obtusiloba var. (?), PI. xxii. Fig. 1.

Dombeyopsis obtusiloba, Lesqx., American Journal of Science and Arts, loc. cit., p. 100.

The specific relation of this fine leaf with those described for the former species is not positive. The general outline of the leaf is the same, as, also,nbsp;the five-palmate nervation, with two lower marginal veins. The first pair ofnbsp;nerves, however, is turned upward on a more acute angle of divergence, andnbsp;the leaf does not appear peltate. In comparing, however, the primary nervation with that of the small leaf of PL xxv, Fig. 2, it will be seen that in thisnbsp;last specimen the inner lateral pair of nerves has in both the same direction,nbsp;and that, too, at the base of each leaf, which in both is destroyed by erosion,nbsp;there is a small marginal border, which looks as if originally joined under thenbsp;point of union of the nerves. Except these differences, the relation is evidentnbsp;by the form, three obtusely-lobed, of the leaf, its round truncate base, thenbsp;direction of the nervilles, the thick substance, amp;c.

Habitat.�The same place as the normal form. This splendid specimen is in the cabinet of the Smithsonian Institution, presented by Prof. B. F.nbsp;Mudge.

Leaves thickish, memibranaceone or snbcoriaceous, triangular in outline, obtusely palmately live-lobed, or deeply undulately lobed, palmately flve-uervod from the enlarged truncate base.

Acer obtusilobum{\), Ung., Lesqx., American Journal of Science and Arts, loc. cit., p. 100.

The study of these leaves, made on the place where I found a large number of more or less fragmentary specimens, near Salina, afforded meansnbsp;of comparison between their forms and nervation; and, from the intermediatenbsp;and transitional characters, I had to admit them as representing a single

species�perhaps even as a mere variety of the former-described ones. These leaves are generally smaller, from 6 to 10 centimeters long, more enlargednbsp;on the sides, from 8 to 12 centimeters broad, broadly triangular, obscurelynbsp;five-lobed or deeply undulately lobed, palmately five-nerved from the base ofnbsp;the leaf, (not peltate,) with the lateral nerves much divided, their ultimatenbsp;� divisions curving along the upper end of the veins and anastomosing in successive bows, all the divisions dissolved or effaced before reaching the borders.nbsp;In the leaves referable to this species, the veins and the areolation, thoughnbsp;thin, are more distinct than in the former species; the divisions of the primary nerves are from the base of the leaves; the middle nerve is comparatively thicker; and the surface of the leaves is smooth. Fig. 4 has the generalnbsp;aspect of a Populus of the coriaceous-leaved section, with somewhat differentnbsp;borders, while Fig. 1 is, by its form, related to the leaf described as Acernbsp;ohtusilobum in Unger�s Chloris Prot., (p. 134, PI. xliii. Fig. 12.)

Le.aves small, triangular or rLomboidal in outline, 3-5 obtusely lobate, wedge-form or abruptly narrowed to the base.

These leaves are of a thinner substance than those of the former species, small, 3 centimeters long and about as wide, 3-5 lobate, with lobes divergingnbsp;from near the middle of the leaves, all obtuse, the middle only slightly acuminate, 3�5 palmately nerved from the broad, nearly truncate, or more gradually attenuated cuneiform base. In Fig. 2 the lateral primary nerves, only two,nbsp;are apparently without branches, and pass up to two lateral lobes. The leafnbsp;(Fig. 3) is five-nerved and five-lobed, with the form somewhat like Fig. 1 ofnbsp;the former species ; the first pair of lateral nerves is divided above the middlenbsp;in two branches, one passing outside toward the borders, the other ascendingnbsp;and curving inside toward the base of the first secondary vein above. Thisnbsp;kind of nervation, and the form of the leaves, too, are so similar to those of thenbsp;leaves of Cocculus (^Menispermum) carolinus, D. C., that I can but considernbsp;them as referable to this genus. The living plant has only a longer and morenbsp;pointed middle lobe of its leaves. The nervation, also, is the same as thatnbsp;of the leaf described by Unger {loc. citl) as Acer obtusilobum.

I^eaves divided ; leaflets thin, lanceolate-pointed or enlarged lobate, with acute lobes; veins pinnate, caiuptodrome.

Of this species, described from a mere fragment, I have been unable to see any other specimen but that 'which is figured. The fragment representsnbsp;two leaflets, apparently attached to a common, pinnately-divided pedicel;nbsp;the lower one deeply bilobate by the forking of the middle nerve, with anbsp;broad, dentate sinus, and lobes entire and sharply pointed ; the upper leaflets,nbsp;(if it is not the lacerated part of the other,) appear simple, lanceolate-pointed,nbsp;entire; secondary nervation simply pinnate in both fragments of leaves, butnbsp;compound in the inner jiart of the lobate leaflet, as it is generally the case fornbsp;a compound leaf Professor Unger, in his Chloris, has described, (p. 135, PI.nbsp;xliv, Figs. 3-6,) as Acer pegasinum, two lanceolate-dentate opposite leaflets,nbsp;upon a common rachis, and which, therefore, appear to belong to a compoundnbsp;leaf like a Negundo. In our N. aceroides, and especially in N californicum,nbsp;the terminal and one of the lateral leaflets become sometimes united into anbsp;compound leaf, with some likeness to this fossil fragment.

Leaves large, oval, tapering upward to a point, and more abruptly narrowed downward to tbo base; borders equally denticulate from below the middle; nervation abnormally five-palmate, craspedodrome.

The description of this species was made out and its name admitted from the examination of the first specimen, (PI. iii. Fig. 2,) a small leaf, witbnbsp;borders indistinct, which did not show the details of conformation wellnbsp;enough. The large leaf, obtained since and represented in PL xxiv.nbsp;Fig. 3, has its borders and its areolation more distinctly marked. The leavesnbsp;are of a thick, subcoriaceous texture, 11 centimeters long, without the petiole,nbsp;from 8 to 11 centimeters broad in the middle, tapering upward, or more ornbsp;less broadly lanceolate to a point, and narrowed, too, more or less abruptly tonbsp;the base; borders equally cut by shallow half-round sinuses, the short teethnbsp;all turned outside; nervation rather pinnate or abnormally five-palmate, as innbsp;some species of Populus; lateral veins at equal distances, ten pairs, oblique,nbsp;diverging about 45�, nearly stiaight, the lowest branching, the upper onesnbsp;simple, all running to the borders, like their divisions; nervilles in rightnbsp;13 L

angle to tlie veins, subcontinuous; areolation platanoidal. There is an apparent difference between the leaves representing this species. The small leaf .(W-iii, Fig. 2,) is more acutely pointed and more acutely tapering to the base,nbsp;where the borders turn to the medial nerve, and follow it, in decurring, to thenbsp;petiole, which is broken in both leaves ; the borders appear mostly entire, andnbsp;the nervation more indistinctly palmate. But in comparing both leaves carefully, these differences are recognized as merely resulting from the developmentnbsp;of each leaf. In the small leaf there is harmony of conformation in the morenbsp;elongated point and base; the denticulation, in its peculiar form, is visible nearnbsp;the point; and at the base the distribution of the lateral nerves compares withnbsp;that of the larger leaf by the two inferior veins of the right side, which arenbsp;narrower, and by the exact coincidence of the two inferior veins of the leftnbsp;side; the lowest, thin, marginal, and simple; the other thick and much divided.nbsp;The leaf of PI. iii. Fig. 4, is apparentl}'-, too, referable to the same species.nbsp;It was described under the nameof Populites Jlahellata in the American Journalnbsp;of Science and Arts, ioc. cit., p. 94; but in comparing it to Fig. 3, it seemsnbsp;to be a mere deformed leaf of a same kind, turned to one side by compression,nbsp;and with the point broken or recurved inward. It has about the same number of lateral veins, the lower appearing more divided, and giving thus a different facies to the leaf; but the same character is recognized in the largenbsp;leaf of PI. XXV, Fig. 3.

I owe to Count Saporta the indication of the relation of this species to Greviopsis, a new genus established by him in the family of the Tiliacece fornbsp;some leaves from the Lower Eocene of Sezane. The Cretaceous species isnbsp;comparable by some of its characters, especially the nervation and the denticulation, to G. crednericeformis, Sap.

Leaves thick, coarsely-veined, ovate or ohovate in outline, either abruptly narrowed, subtruncate, and subcordate to the petiole, or rounded, wedge-form to the base, irregularly lobate on one side, deeplynbsp;undulate on the borders j nervation irregularly 3-5-palmate from above the base of the leaves; primarynbsp;veins much divided.

Quercus semi-alata, Lesqx., American Journal of Science and Arts, loc. cit., p. 96.

present the most variable forms and greatest differences in their nervation. As seen in Fig. 1, the general outline is ovate, obtuse, with the bordersnbsp;entire or merely undulate on one side, while the other side is deeply lobed bynbsp;the prolongation of a basilar secondary nerve nearly as thick as the medialnbsp;one, branching outside with the divisions subcamptodrome. In this leaf thenbsp;nervation is evidently irregularly pinnate from the base of the leaf, whichnbsp;appears rounded to the petiole ; the lateral veins are parallel on one side,nbsp;though at unequal distance, while on the other side the angle of divergencenbsp;is variable, and all the divisions are camptodrome, or rather subcamptodrome,nbsp;as the point of the veins passes to the borders, while some of the divisionsnbsp;follow the borders in successive curves. Though the leaf of Fig. 2 is brokennbsp;on one side, it evidently shows, however, a disposition to a division by lobenbsp;on the left side, where the lateral veins are less numerous, but thicker andnbsp;more branched than on the right. The division of the nervation appearsnbsp;here to be three-palmate; two thick opposite lateral primary nerves branching at a distance above the basilar borders of the leaf, rounded on one side,nbsp;broadly cuneate on the other, with two thinner lower veinlets on the left sidenbsp;only. This division is platanoidal on one side, and of the Credneria typenbsp;on the other. In Fig. 3 the same kind of one-sided division is still evident bynbsp;the disposition and thickness of the lateral primary veins, which are here bynbsp;five, high above the border of the truncate base of the leaf, and with inferiornbsp;lateral thinner veinlets nearly at a right angle to the thick medial nerve. Fig.nbsp;4 is, too, of the same type by the one-sided division: a lobe being indicatednbsp;by the lateral nerve of the right side, while on the other the division and thenbsp;thinning of the nerve show that it ends without entering a prolongation of anbsp;lobe. In this leaf the borders are cuneate to the base; the lower lateralnbsp;veins under the primary ones go out of the medial nerve in the same angle ofnbsp;divergence; and as in the other leaves, the divisions of the lateral veinsnbsp;are mostly camptodrome, while the secondary veins are mostly craspedodrome.nbsp;In Fig. 5, the three-palmate nervation is still more marked, and the extensionnbsp;of the leaf on one side evident by the extraordinary thickness of the basilarnbsp;nerve on the left side. I have figured this fragment, though incomplete it is,nbsp;because it is the only one which shows the whole base of the leaf with anbsp;petiole. The junction of the borders to the petiole is equally abnormal;nbsp;the leaf being on one side round cordate, and on the other round wedge-form.

100

of the discordance of their characters. A similar kind of variability is remarked only, I think, in species of Quercus. Some leaves of oaks have thenbsp;double nervation camptodrome and craspedodrome upon the same leaf; somenbsp;others show a disposition to an unequal expansion of the limb on one side ornbsp;on the other, in relation to the unequal division of the veinseven a nervation somewhat analogous to that of these leaves is remarked in some fossilnbsp;species, as in Quercus desloesi, Heer, Q. charpentieri, H., Q. agnostifolia, H.,nbsp;amp;c. But this relation is too far; the type is evidently original, and for thisnbsp;reason it had to be separated as of uncertain affinity.

Leaves generally of large size, thick, coriaceous, broadly oval or round-pointed, suhpeltate; borders entire or undulate; nervatiou palmato-pinnate; lower primary lateral veins at a distance from thenbsp;border-base, with more or less numerous veinlets underneath, either iu right angle to the middle nervenbsp;or diverging downward J upper lateral veins at equal distance from the lower pair and parallel, allnbsp;craspedodrome.

In my examination of the numerous leaves described in this division, and which I have previously referred either to Credneria or to Pterospermites,nbsp;I have never been able to recognize characters which might satisfactorilynbsp;account for this reference. If some of the leaves, like that of PL xvi, of PLnbsp;xvii, Fig. 1, or of PL xviii. Fig. 2, are referable to Credneria on accountnbsp;of their size, their form, and the lower horizontal veins at the base of thenbsp;leaves under the primary divisions, they do not show the characters indicatednbsp;by Zenker in the diagnosis of this genus in Paleont., V. II, p. 63, viz : Caulisnbsp;polygonearum, folia ohovata, hasi suhcordata, longe-petiolata, nervi primarii suh-erecti, etc. In regard to the nervation, all the Credneria leaves figured in thenbsp;same work with entire borders have a camptodrome nervation; those withnbsp;craspedodrome secondary nerves are dentate or lobed. In the beautifulnbsp;leaf described by Heer iu Molet. FL, (p. 16, PL iv,) as Credneria macrophylla,nbsp;which, judging from our fragmentary specimen of Credneria leconteana, (PLnbsp;xvii. Fig. 4,) is related by its form to the American species, the camptodromenbsp;nervation is positively marked.

Now, besides this difference between the European Crednerice and all the Cretaceous leaves, with borders entire, which I have I'eferred, until now,nbsp;to this genus, these still differ from the characters of Credneria by the overlapping of the border-base upon the petiole. These leaves are generally

subpeltate, and therefore they should be referable to Pterospermites. The analogy of some of these leaves to those of the living Pterospermum acerifolium, Wild., is indeed evident. In this, however, the essential nerves, three or five,nbsp;end into the point of a lobe, while all their branches and the intermediatenbsp;nerves are camptodrome. And though the base of the leaves is overlappingnbsp;and covering, by its broad auricules, the upper part of the petioles, all thenbsp;lower veins come out from the top of the petiole, and there is no trace of thenbsp;horizontal vinelets, which are remarked, without exception, in all the speciesnbsp;which I describe in this new genus. I do not know of any leaves of Ptetnbsp;ospermites but those which are described by Heer from Greenland. Innbsp;FI. Arct., (p. 480, PL xliii. Fig. l��, PI. liii, Figs. 1-4, and PI. liv. Fig. 3,)nbsp;the author has described two species, Pterospermites spectabilis and P. alter-nans, whose nervation and cordate base are of the same character as in thenbsp;species of Credneria, the only difference being in the size of these leaves,nbsp;which appear smaller. Of these fragments. Fig. 15'quot; is comparable, by itsnbsp;basilar nervation, to the Cretaceous leaf of this memoir, (PI. xvii, Fig. 3,)nbsp;which, however, differs from the Greenland species by its craspedodromenbsp;nervation. In the same work. Heer has (p. 122, PI. ix. Fig. 14a) Pterospermites integrifolius without any horizontal basilar nerves, the medial nervenbsp;passing under the border-base of the leaf or peltate, and (p. 138, PI. xxi. Fig.nbsp;17��, and PI. xxiii, Figs. 6, 7,) he represents Pterospermites dentatus with anbsp;peltate leaf and basilar veins running down from the base of the medialnbsp;nerve, or with secondary veins at right angle to it. It is, therefore, difficultnbsp;to know by what characters the genus Credneria may be positively separatednbsp;from Pterospermites^ besides that of larger-sized leaves for the former genus,nbsp;and of more or less peltate ones for the second. Some of our peltate leaves,nbsp;however, referable to Pterospermites by the nervation, have leaves, as remarked already, as large as those of Credneria. Having, therefore, tonbsp;describe a number of forms which, though related to the yet undefinednbsp;genera Credneria and Pterospermites, are forcibly removed from them bynbsp;some important characters, I have united them all in this new division.

Leaves largo, coriaceous, entire, round or cordate at tlie base, narrowed upward into a slightly obtuse point; basilar nerves one or two pairs.

102

Its size, form, and nervation are, however, definite. It is at least 20 centimeters long, 19 centimeters broad in its widest part above the base, where it is rounded downward to the petiole ; tapering upward, or narrowed in undulating entire borders, to a slightly obtuse point; medial nerve half-round,nbsp;comparatively narrow; secondary veins mostly opposite, branching once,nbsp;rarely twice, all craspedodrome; basilar veins two pairs, the upper one in anbsp;right angle to the medial nerve, forking; the lower simple, thin, somewhatnbsp;deflected downward. This last character is marked by the end of one of thenbsp;basilar veins, distinctly seen near the border-base on the left side ; and it isnbsp;still more defined in the smaller leaf, (PI. xviii. Fig. 2,) which is subpeltatenbsp;by the border-base of the leaf covering the petiole.

In the eight figures of leaves of Credneria which Stiehler (in Paleont., loCi cit?) has published, the basilar veins are thinner than in our large leaf,nbsp;but not more so than in the small one; and in all the European leaves referrednbsp;to Credneria, the second pair of lateral veins is at a greater distance from thenbsp;lower pair than from those above, even in the leaves with entire borders. Theynbsp;have, therefore, a general appearance more resembling that of species of Platanus. In the American leaves, this difference does not exist; on the contrary,nbsp;the secondary veins are at about the same distance, except near the base,nbsp;where the lower pair, which may be considered as a marginal one, thoughnbsp;still of the same thickness, is nearer to the pair above. These secondarynbsp;veins are also more numerous. In this species there are nine to ten pairsnbsp;running straight to the borders, which they enter as craspedodrome, while thenbsp;European leaves have only four to six pairs, all the veins curving up in ascending to the borders, with mostly camptodrome divisions. These differences arenbsp;somewhat less marked, but evident, however, in the fine leaf which Heer hasnbsp;described in the Cretaceous Moletin Flora as Credneria macrophylla, (PI. iv,nbsp;p. 16,) and which, besides, widely differs from ours by its very thick medialnbsp;nerve and its camptodrome secondary veins. It is of the same size and ofnbsp;the same form, however. Heer rightly remarks, in describing this species,nbsp;�that the systematical relation of the genus Credneria is still very uncertain.��nbsp;The same can be said of the species in relation to this genus, or of the relation of the leaves referred to it.

liahitat.�South of Fort Harker, in a locality discovered by Chs. Sternberg ; both leaves.

Leaves coriaceous, round, more enlarged in the middle, entire; medial nerve thick; lowest secondary veins much divided; basilar veins in right angle to the medial nerve, proportionally thick.

Crednerwj leconteana, Lesqx., American Journal of Science and Arts, loc. cit., p. 98.

This species is represented by two fragmentary leaves, with the lower part destroyed in both. The nervation is of the same type as in the formernbsp;species, differing, however, by the greater thickness of the medial nerve andnbsp;by the more numerous divisions of the lateral veins. In both species thenbsp;divergence of these veins is the same, (40� to 70�,) gradually increasing innbsp;width from the top to the base, and in both, also, the veins and their divisions run to the borders, where they become more or less effaced by thenbsp;anastomosis of the nervilles, which are coarsely marked, in a right angle tonbsp;all the divisions of the veins, and more or less continuous. Besides the difference marked in the character of the nervation, this species is still furthernbsp;separated from the former by its round outline and broadly obtuse point.

Habitat.�Brooksville, Kansas, Leconte; the small specimen from south of Fort Harker. The localities where the specimens of Dr. Leconte werenbsp;obtained (three miles northeast of Fort Harker and near Brooksville) arenbsp;eight to ten miles north of the one where I mostly collected my own, whichnbsp;are marked in this report as near Fort Harker.

Leaf small, subcoriaceous, oval-oblong, broadly cunoate to the petiole; borders entire; medial nerve, thin ; secondary veins close, parallel, all under the same angle of divergence.

This leaf differs in its characters from those described from Kansas. It is comparatively very small; its surface somewhat rough, though its substance is not as thick; the form is oval-oblong, the borders in the middlenbsp;being apparently parallel, and its base is rounded broadly-conical to the petiole;nbsp;the secondary veins, all under the same angle of divergence of 40� to 50�, arenbsp;thin, parallel, camptodrome, straight, with a single thin marginal veinlet onnbsp;each side from below the lowest pair of the secondary veins. This vein followsnbsp;the borders, anastomosing with nervilles of the divisions of the lower veinsnbsp;which are camptodrome, while the primary divisions are craspedodrome.nbsp;The leaf is not peltate, the narrow primary nerve being prolonged into a short,nbsp;apparently broken petiole. It may be compared to Credneria integerrima,nbsp;Zenker, as represented in Paleont., (Vol. V, PI. ix, Fig. 2,) which has

about the same basilar form, and also on each side one single basilar veitilet, anastomosing in following the borders with the divisions of the vein above.nbsp;But the dilference is great indeed, especially in the narrow medial nerve ofnbsp;the American leaf, in its straight, craspedodrome, secondary nerves, and itsnbsp;form.

Habitat.�Hills near Decatur, Nebraska; the only leaf as yet referable to Protophyllum from that State.

Leaf tMokisli, round-square in outline, truncate at base, subpeltate, deeply undulate, obtuse; nervation thick, craspedodrome.

Leaf large, 13 centimeters both ways, coriaceous, deeply undulate, sub-peltate ; secondary veins thick, moderately branching, at an open angle of divergence, parallel; basilar veins open, the lower pair at right angle to thenbsp;the medial nerve, even curving downward, with two thin veinlets under them,nbsp;decurring down the border-base which covers the petiole, either continuous ornbsp;auricled. This leaf is not comparable to any published until now from thenbsp;Cretaceous flora of Europe.

Habitat.�South of Fort Harker, where I found it in numerous specimens, none, howeverj as perfect as the one figured here, which was communicated by Professor Mudge.

Leaves coriaceous, small, ovate, largest near the base, truncate or abruptly rounded, entire or slightly undulate on the border, subpeltate.

This species is, perhaps, a variety of the former. The leaves are smaller and less deeply undulate, but the general facies is the same. The secondarynbsp;veins are more numerous or less distant, but straight to the borders in bothnbsp;species, and the disposition of the marginal veins at the base, like the subpeltatenbsp;basilar borders, are also of the same character. In Fig. 2 of PI. xix, the secondary veins, though running to the borders, do not mark them with undulations or small, slightly-protruding lobes. The borders of this leaf are, however, apparently somewhat reflexed and imbedded into the stone in such anbsp;way that the outside margin cannot be distinctly seen. It is separated fromnbsp;the former species by the differences indicated. Perhaps intermediate formsnbsp;may be found hereafter.

Habitat.�Salina River, hills eight miles above its mouth. The small specimen (PI. xxvii, Fig. 1) was communicated by Professor Mudge fromnbsp;Fort Lamed, Kansas.

Leaf of medium size, coriaceous, oval-oblong, round-truncate at tUo base, peltate; medial nerve thick; lateral veins close, parallel, numerous; borders entire or undulate.

The figured fragment is the most perfect among many others referable to the same species. It is 12 centimeters long, (its upper part is broken,) 11nbsp;centimeters wide a little above its base, where it is slightly enlarged and thennbsp;rounded downward and truncate; its borders are nearly parallel, slightly undulate ; its medial nerve is comparatively thick, like the numerous, opposite, nearlynbsp;parallel secondary veins, whose angle of divergence is more and more opennbsp;toward the base, the lower veins running down from the point of attachmentnbsp;of the peltate leaf in various degrees of inclination, across the broad border-base, which is at least one centimeter wide. This impression of the leaf isnbsp;apparently that of the lower side, and the petiole has been broken just at thenbsp;base of the medial nerve. The distinction between the secondary veins andnbsp;the marginal ones is not clear on account of the similarity of the veins innbsp;their thickness and of the slow degree of change in their angle of divergence. Counting from the lowest, thick, branching lateral veins to the uppernbsp;jiart where the leaf is broken, there are ten pairs of secondary veins in a spacenbsp;of centimeters, and under them four or five.deflexed smaller veins on eachnbsp;side of the middle nerve near and at its base.

Leaves deltoid-ovate, rounded at the subpeltate base; borders entire; nervation coarse ) secondary veins irregular in distance and direction.

The leaves, of a thick coriaceous substance, have a rough surface, deeply furrowed and wrinkled by the veins and the nervilles; they vary in size fromnbsp;six to twelve centimeters long and from five to nine centimeters wide. Theynbsp;are broadest below the middle, rounded truncate at base, the borders taperingnbsp;to a deltoid point. The middle nerve is not as thick as in the former species,nbsp;becoming thicker, however, toward its base. The secondary veins are placednbsp;14 L

at irregular distances, curving in various directions, less parallel than in the other species, with only two or three marginal veinlets at right angles to thenbsp;medial nerve, but none descending into the narrow border below the point ofnbsp;attachment of the petiole.

Fig. 3, PI. xix, is a fragment of a smaller leaf, which has the same rough surface as the others of this species. It has, too, the same irregularity in thenbsp;distance of its secondary veins, but the base of the middle nerve is not thickened, and is more prolonged downward, forcing a deflection of the borders,nbsp;and thus a less truncate or more wedge-form base.

Leaves small, coriaceous, smooth, ovate-oblong, pointed, deeply and irregularly undnlate-lobed, abruptly rounded to the base; secondary veins parallel; basilar veins thin, undulate, two or three onnbsp;each side of the medial nerve, at a right angle to it.

Besides other more fragmentary specimens, the species is represented by a leaf 9 centimeters long, 5 to 6 centimeters wide, oblong, broadly lanceolate-pointed, deeply undulate all around or irregularly marked on the bordersnbsp;and in the middle by short, obtuse, irregular lobes; strongly pinnately-veined tonbsp;the base, with lateral veins thick, parallel, all under the same angle of divergence of 50�, and thin, simple basilar veins at a distance of the lateral onesnbsp;and near the base �f the leaf, diverging at a right angle from the medialnbsp;nerve, flexuous, three on one side and two on the other. The secondarynbsp;veins are less branched than in any of the former species. I have comparednbsp;this species, in report loc. cit., to P. spectahilis. Heer, (FI. Arct,, p. 480,nbsp;PI. xliii. Fig. 15^) The leaf has, indeed, some likeness to it by its generalnbsp;outline; but the direction of the more numerous and craspedodrome lateralnbsp;veins in the Cretaceous leaf is far different.

Leaf coriaceous, ovate, obtuse, enlarged and truncate at the base, equally denticulate; medial nerve very thick; secondary veins alternate, thick, more or less branching, craspedodrome.

Leaf ovate, apparently tapering to an obtuse point, (the upper part is broken,) 6 centimeters broad near the base, where the leaf is the largest.

truncate; nervation very coarse and deeply marked; secondary veins more or less branching, entering each, vrith their divisions, the point of a tooth.

The denticulation of the borders of this leaf is of the same character as that remarked in Greviopsis haydenii, viz, shallow teeth pointed outward,nbsp;separated by equal, obtuse sinuses; the lateral veins nearly parallel, join thenbsp;medial nerve under a broad angle of divergence of 50� to 60�. Dunker innbsp;the Paleont., (vol. iv, p. 181, PI. xxxiv. Fig. 1,) has described, from thenbsp;Quadersandstein of Blankenburg, a leaf or a fragment under the name ofnbsp;Castanea hausmanni, which is somewhat related to our species. The denticulation is, however, unequal; the tertiary veins stronger; the base of the leafnbsp;round. I refer this leaf with doubt to this section.

Leaf peltate, kidney-shaped, with an entire hroadly-truncate base; borders dentate by equal hastate or auricled teeth; nervation seven-palmate.

Ficus (J) Jimhriata, Lesqx., American Journal of Science and Arts, loc. cit.., p. 96.

The leaf is peltate from the union of the borders a little lower than the point of attachment to the petiole; its form is nearly round, enlarged on thenbsp;sides or kidney-shaped, entire and truncate at the enlarged base, equallynbsp;dentate from its lower part, with equal short teeth, appendaged withnbsp;obtuse auricles, and separated by deep half-round sinuses; j^etiole thick,nbsp;attached above the borders, which are joined under it in a very obtuse angle ;nbsp;nervation seven-palmate; veins diverging at equal distance, of the same thickness, except the middle nerve, which is slightly stronger, forking once ornbsp;twice from above the middle, with the divisions turned toward, but not entering, the teeth; areolation small, round, polygonal.

The relation of this leaf is still more uncertain than that of the former species. By the round form of the leaf, it is comparable to Ficus crenatanbsp;Ung., (Sillog., p. 14, PI. vi. Pig. 3,) a round, subpeltate leaf, with a seven-palmate nervation, or to Ficus asarifolia, Ett., (Bilin. Flor., p. 80, PI. xxv,nbsp;Fig. 3 ;) also a subpeltate, nearly round leaf The relation is, however, distant.nbsp;I have not been able to find, either in living plants or in the descriptionsnbsp;and figures of fossil ones, anything analogous to the kind of denticulatenbsp;appendages which surround this Cretaceous leaf, and have therefore sepa-

rated it under a new genus, whose characters are those of the species. The substance of the leaf is membranaceous, its surface smooth, the veins distinct,nbsp;and the areolation recognizable near the middle jjart, where it is mrkaed asnbsp;it is seen with the glass. The enlarged figure of the borders underneathnbsp;show the foliaceous appendages of the teeth; some of them are curvednbsp;downward, and appear obtuse and truncate.

Leaf small, membranaceous, oval-obtuse, entire, palmately tbree-nerved from the base; lateral nerves thin ; nervilles distinct, perpendicular to the nerves and joining them.

Paliurus membranaceus, Lesqx., American Journal of Science and Arts, loc. cit., p. 101.

The only leaf by which this species is represented is of a thickish membranaceous substance, with a polished surface: oval, very obtuse, rounded to the base by a less obtuse curve, with a comparatively thick medial nervenbsp;ascending to the upper border of the leaf, and two thin lateral veins going upnbsp;from the base to two-thirds of the leaf in an acute angle of divergence of 20�.nbsp;The middle nerve is branching in its upper part; the lateral ones are alsonbsp;branching outside; all the subdivisions are simple, slender, on a broad anglenbsp;of divergence, most resembling the nervilles, which, from the middle of thenbsp;leaf downward, join the middle nerve to the secondary ones. The leaf (4Jnbsp;centimeters long and 3 centimeters wide) is apparently petioled, its basenbsp;curving down as slightly decurring to a broken petiole.

From the numerous Tertiary species of Paliurus, to which this one is comparable by its nervation, it differs especially by its very obtuse leaf.nbsp;ZizypTius protolotus, (Ung., in Pleer, FI. Tert. Helv., Ill, p. 74, PI. cliv. Fig.nbsp;32,) represents, however, a still more round-obtuse leaf, but different in thenbsp;type of its nervation.

Leaves coriaceous, very thick, linear, abruptly narrowed to the base by a round curve, broadly deltoid-pointed; medial nerve very thick; secondary veins thin, close, parallel, open, camptodrome.

The species is represented by two leaves, one 12 centimeters long and 6 centimeters wide, and the other only 8^ centimeters long and 3J centime-

ters broad, both having the same form: linear, abruptly rounded to the petiole, and curving or deflexed to it, nearly truncate or broadly deltoid at the point.nbsp;Both leaves, also, have a comparatively thick medial nerve, and thin, more ornbsp;less obsolete secondary veins, emerging at a broad angle of 50� to 60�, undulating in passing to the borders, and anastomosing with branches of the veinsnbsp;above, camptodrome.

There is apparently a great difference between these two leaves, especially in the borders, which in Fig. 3 are merely undulate, while in the large leaf they appear undulate-crenate, a character which, to my knowledge, is notnbsp;recognized in any living species of the Magnoliacea nor of the AnonacecB,nbsp;some of which have a nervation and areolation somewhat similar to that ofnbsp;this leaf This denticulation of the borders, however, may not be normal.nbsp;In the upper part of the large leaf, especially on the right side of the figure,nbsp;the denticulation is more marked than seen upon the specimens, whosenbsp;borders are somewhat obscurely marked or as reflexed, and not more deeplynbsp;undulate than as they are seen on the left side.

I have referred these leaves, as advised by Saporta, to the genus Celas-trophyllum, Ett., one species of which is described in the Cretaceous Flora v. Niedershoena, (p. 26, PL iii, Fig. 9,) under the specific name of C. lanceolatum.nbsp;The reference of our leaves to this genus is not, however, 23ositive; but theirnbsp;relation is still less marked with Magnolia crassifolia, Gopp., of the Tertiarynbsp;of Silesia, to which I compared them formerly. The areolation is representednbsp;in Fig. 3 as distinctly as it can be seen. Though the end of the veins isnbsp;effaced near the borders, they appear really camptodrome. This nervationnbsp;has its analogy in species of Oxandra, as O. laurifolia, Rich., of Cuba, ofnbsp;which some of the leaves, at least, are abruptly pointed or obtusely acuminate.

Leaf entire, lanceolate-pointed, narrowed Uy a curve to a short petiole; lateral veins close, numerous, thin, parallel.

A fine leaf, attached to a branch by a short petiole. Its substance is not thick; its form lanceolate, tapering ujiward to a slightly obtuse point, andnbsp;more abruptly downward from below the middle to the petiole. It is 9 centimeters long, with the petiole, which is about one centimeter and a little morenbsp;than two centimeters wide in its broadest part. The thin lateral veins are

110

parallel, except the basilar one, which, following the curve of the borders, is on a slightly more acute angle, numerous, fifteen to sixteen pairs, under anbsp;general angle of divergence of 50� ; they slightly curve in ascending towardnbsp;the borders, where they bend, and which they follow, to anastomose with thenbsp;vein above; the nervilles are numerous, obsolete, parallel to the veins. Bynbsp;its form, its short, slightly enlarged petiole, and its nervation, this leaf appears,nbsp;indeed, referable to Rhamnus, and has its analogies in a number of species ofnbsp;the American Tertiary like Rhamnus salicifolius, Lesqx., R. cleburni, amp;c.,nbsp;which all, however, have much thicker secondary veins.

Leaves coriaceous, entire, broadly ovate, obtuse, or witb a short obtuse point, roundcd-subcoxdate at the base or narrowed downward by a curve, and slightly decurring to the petiole j medial nerve thick jnbsp;secondary veins numerous, open, camptodrome.

101.

From a single specimen submitted to his examination. Professor Fleer referred the leaf with doubt to Populus. A large number of good specimensnbsp;of leaves of the same species have been procured later, and some of the morenbsp;diverse forms figured in this memoir. These leaves vary from a broadlynbsp;ovate-obtuse to an elliptical form, the borders being always entire, rarely slightlynbsp;undulate, as in Fig. 1. The base is either slightly decurring to the petiole ornbsp;round-cordate; and though the borders are generally equilateral, they sometimes are more enlarged on one side, and the leaves, or rather leaflets, are curvednbsp;on one side, as in Figs. 4 and 5. This deviation, and also the difference in thenbsp;direction of the borders, as seen in comparing Figs. 1 and 3 to Fig. 2, indicatesnbsp;a compound leaf: Fig. 2 representing a principal or top leaflet, the others representing lateral ones. The nervation is rough and very distinct upon the impressions of the lower side of the leaves, as in Figs. 2, 4, and 5. The secondarynbsp;veins are numerous, twelve to fourteen pairs, (in the leaf Fig. 2, which is 8 centimeters long,) on an open angle of divergence averaging 60�, thick, variable innbsp;distance, more or less parallel, separated by tertiary shorter veins forming, bynbsp;anastomose with the nervilles, a net of irregular, large, mostly quadrangular

meshes; the veins and their divisions curve along the borders in a succession of short flexures. This nervation is somewhat like that of some leaves ofnbsp;Juglanso� the European Tertiary: for example, Juglans latifolia, Heer, (Flor.nbsp;Tert. Helv., Ill, p. 88.) especially as marked in PI. cxxix, Figs. 3, 6, and 9.nbsp;However, the reference of these leaves to Juglans is far from positive, thenbsp;nervilles being more irregular and the veinlets more irregularly divided thannbsp;in any species of Juglans. A more analogous nervation to that of this speciesnbsp;is remarked in some species of Rhus, as in R. metopium, which has coriaceousnbsp;leaves, slightly cordate, and of forms somewhat resembling those of the fossilnbsp;leaves.

Habitat.�Decatur, Nebraska, Hayden ; a large number of specimens. Phyllites EHOiFOLius, Lcsqx., PI. xxii. Figs. 5, 6.

Leaves coriaceous, lanceolate, penninerve, irregularly ol)tusely crenate; medial nerve tliiok; secondary veins parallel, camptodrome.

The two fragments of leaves, represented in the figure, are of very uncertain relation. As seen in Fig. 6, the leaves of this species appear to have been enlarged on one side and somewhat lobate at the base, or of annbsp;irregular form. As in our Rhus toxicodendron, the secondary veins are thick,nbsp;on a broad angle of divergence, eurving along the borders, where they unitenbsp;with oblique obscure nervilles. I compared it, for the nervation, (in thenbsp;journal quoted above, 2, xlvi, 1868,) to R. cotinoides, one of the numerousnbsp;varieties of the poison-ivy.

Drupe ovate, obtusely pointed, smooth, grooved on one side to the middle, notched at the enlarged obtuse base.

The form of this small, hard fruit is like that of the drupe of a plum, or of a large cherry. Another nutlet of about the same form, but compressednbsp;and flattened, is imbedded in the stone, its back and part of the sides onlynbsp;being visible, as seen in Fig. 9.

112

Leaves small, mostly in fragments, round-ovate, truncate at the top, narrowed to the base by a round curve; borders dentate; nervation pinnate, irregular, craspedodrome.

Phyllites hetuloefolius, Lesqx., Transactions of the American Philosophical Society, vol. xiii, p. 430, PI. xxiii. Figs. 2-4.

These fragments, though far different in form and size, appear to belong to the same species. All the leaves are marked on the borders by shortnbsp;teeth, turned outside; the secondary veins, at various distances, are more ornbsp;less open, mostly branching, entering the teeth by their points or those ofnbsp;their divisions, and joined by strong flexuous nervilles, perpendicular to thenbsp;veins and undulate. The consistence of the leaves is thickish. They appearnbsp;to have been petioled, at least from the narrowing of the base of the leaves innbsp;Figs. 5, 7, above the line of disruption.

Habitat.�Fort Harker, Dr. Leconte; the fragment of Fig. 4 is from Nebraska, Prof. James Hall.

Leaf rbomboidal, broadly cuneato to tbe base, more obtusely narrowed and undulate from the middle to an obtuse short point; nervation five-palmate from the base, the two inner lateral veins curving up at a very acute angle of divergence and aerodrome, or nearly reaching the point of the leaf, branching outside, the external veins following the borders up to the middle of the leaf, where they anastomose with branches of the first pair.

Ficus (?) rhomhoidea, Lesqx., American Journal of Science and Arts, loc. cit, p. 96.

A remarkable leaf, which, by its form and nervation, somewhat resembles the leaf of a Smilax, a Paliurus, or a Populus, and which, by its thick consistence and thick nervation, is different from any species of these genera.nbsp;Its form is nearly exactly rhomboidal, being, however, more acutely cuneatenbsp;and entire from the enlarged part, the middle, to the base than to its obtusenbsp;point, where it passes by undulations. Its five-palmate nervation is from anbsp;slightly enlarged base, apparently the top of a broken petiole. The generalnbsp;form of the leaf is like that of Populus arctica, Heer, as represented in Floranbsp;Arctica, (1, PI. v. Fig. 3;)�even the direction of the five primary veins is aboutnbsp;the same; but the veins are thicker, as is also the texture of the leaves, andnbsp;these veins are less branching. Moreover, the base of the leaves in thenbsp;Arctic species is always more enlarged, generally round or truncate. The

same analogies and differences are remarked between this leaf and that of Populus leuce, described by Unger, (Flora v. Sotzka, p. 37, PL xv, Fig. 6.)nbsp;From its nervation, our leaf seems to have also some relation to speciesnbsp;of Ficus of the palmate-nerved section, like Ficus asarifolia, Ett., Ficusnbsp;crenata, Unger, and Ficus grocnlandica, Heer, (Flora Arctica, p. Ill, PL xiii.nbsp;Fig. 6.)

Leaves small, ovate-lanceolate, pointed, cuneiform to the base; borders entire; medial nerve thin ; secondary veins few, scattered, camptodrome.

Phyllites vanonce, Heer, Phyllites du Nebraska, p. 22, PL i. Fig. 8.�Lesqx., American Journal of Science and Arts, loc. cit., p. 102.

The form of the leaf of PL xxviii. Fig. 8, as far, at least, as regards its cuneate base, and the rare, lateral scattered veins, are the only characters whichnbsp;mark the identity of the two leaves figured as above. The substance of thesenbsp;leaves is rather membranaceous or thickish.

Apparently a deformed leaf, quadrate in outline, truncate at the base, deeply notched at the top by the splitting of the thick medial nerve, irregularly broadly undulate-lobate on the borders ; secondary veins few, at irregular distance, nearly at right angle to the medial nerve, curving in passing tonbsp;the borders, craspedodrome.

Two fragments of coriaceous, obovate, entire leaves, gradually narrowed to the base, (broken;) medial nerve deep and narrow; secondary veins either in right angle to the medial nerve or curvednbsp;downward or going up in an acute angle of divergence, branching and anastomosing in various abnormalnbsp;ways.

I know nothing more about these fragments but what is described above. They are comparable to some species of Quercus by their nervation, at least.nbsp;Habitat.�Decatur, Nebraska, Hayden.nbsp;iSL

Cone oblong or cylindrical, bearing small oval seeds, attached to oval-oblong wings or scales.

This name is admitted for the description of a strobile, whose relation is as yet uncertain, as may he seen from the description of the species.

The figure represents, as far as it is distinguishable, a cone two to three centimeters wide, oblong, crushed, or, rather, cut in its length and by thenbsp;middle, exposing numerous small, oblong-oval seeds, convex or lenticular-obtuse at one end, pointed downward, regularly striated lengthwise. Thesenbsp;seeds are apparently crushed, and their relative position is undiscernible, except for a few which appear imbricated in an oblique row along the borders.nbsp;They are attached to salient wings, oblique to the axis of the cone, and joinednbsp;to the seeds, as marked in the enlarged figure. It is, however, possiblenbsp;that the dark ring, marked as the base of the scale at its point of unionnbsp;to the seeds, is only formed by a fragment of the coating of coaly matternbsp;which envelops the seeds, as seen in the figure, which shows a seed withnbsp;part of the coating destroyed, and, therefore, that the scale is not superposed to the top of the seeds, but passes to the base behind it or invelops it, asnbsp;in some species of conifers. In this case, the cone would present an appearance somewhat similar to that of Cunninghamites oxycedrus, as figured in Ett.nbsp;Cret. Flor. v. Nieders., (PI. i. Fig. 9,) supposing, however, that the scales ofnbsp;this cone, which appear broken, should have been longer and oval-lanceolate.nbsp;In the Nebraska strobile, these scales are striate in the length as in those ofnbsp;the cone of Niedershoena. I am not able to find any other point of comparison for this fossil.

When I broke open the stone, the vegetable impressions were very distinct ; the scales or wings, like the seeds, being sharply defined and painted black upon the yellowish sandstone. By exposure to the atmosphere, thenbsp;coloring has become less distinct, and the specimen now presents the appearance as seen in the figure.

Habitat.�Warner�s quarry, eight miles northeast of Winnebago Village, bluffs of the Missouri River.

affinity. I was at first disposed to regard it as a mere sandstone concretion, and, therefore, as inorganic; but I found at the same locality. Blackbird Hills,nbsp;two other specimens, which, though somewhat different in form and sizenbsp;seem to indicate their origin as vegetable. The one figured (PI. xxvii) isnbsp;oval, pointed at both ends, costate, apparently marked at the lower end by anbsp;small hollow, surrounded by round small bolsters, as seen at the end of thenbsp;costae. The second is oblong-oval, smooth or without ribs, more abruptlynbsp;rounded at one end, and truncate at the other, with a distinct round excavation in the middle, like the scar of a detached pedicel. The third is smaller,nbsp;but about of the same form as the first, and costate. These fruits (I) couldnbsp;be compared to some nuts of palms, or to fruits related to the Nipadites ofnbsp;Bowerbank, from the Eocene of England, but the analogy is questionable.nbsp;In some exposures of the sandstone of this formation, as, for example, nearnbsp;Brooksville, Kansas, and between Tekamah and Decatur, there is an abundance of round, smooth, perfectly regular concretions, generally called nuts bynbsp;the farmers, and considered as petrified walnuts or fruits of palm, amp;c. Fromnbsp;the examination of a large number of them, they are positively recognized asnbsp;mere ferruginous concretions. The so-called Carpolithes, described above,nbsp;may be of the same kind. An exactly round form and a same size for a number of specimens of concretions is, however, more easily explained than a kindnbsp;of relation by characters, which, like the hollow for a pedicel at one end, ornbsp;an equal disposition of ribs, amp;c., are not generally the result of mere inorganicnbsp;agglomerations.

Stem or branch cylindrical, centimeters in diameter, with its surface rough, marked by irregular, close, dots or small cavities resembling the impressions of scales. The stem apparently bears strong spines at a right angle;nbsp;their hollow, cylindrical scars are seen perforating the stone. These smallnbsp;stems or branches resemble, by the rough surface, the fragments describednbsp;by Ettinghausen as Caulinites stigmarioides, (Flora v. Nieders., p. 14, PI. ii.nbsp;Fig. 1;) the dots, however, being closer in our stem, and about round, or notnbsp;so much transversely enlarged. The fragments, mostly imbedded and visible only at their ends, could not be figured.

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Though the formation of the Dakota group is in immediate superposition to the Permian or the Upper Carboniferous measures, we cannot, of course,nbsp;look for any remains of Permian vegetable types in this American cretaceous.nbsp;We should, perhaps, expect to find there some representatives of the preceding formation, the Jurassic, wbose flora is a compound of Ferns, few Equise-tacece, some Conifers, and especially a prodigious abundance of Cycadece.nbsp;Three-fourths of all the fossil Zamice, nudi half of the Cycadece, known fromnbsp;all the geological formations, belong to the Jurassic. In the Lower Cretaceous of Greenland, Heer finds still a marked proportion of species ofnbsp;this family, there being nine Cycadece in a group of tfiirty-six species ofnbsp;land-plants, a proportion of 35 per cent, of the land-flora of that epoch asnbsp;far as it is known. In the Dakota group, the only trace of a vegetable possibly referable to the Cycadece is the Pterophyllumif) haydenii, which,nbsp;as it is remarked in the description, is considered by Schimper as of doubtful affinity. Professor Heer, too, finds in the Upper Cretaceous of Greenland a flora of twenty-eight species, mostly of dicotyledonous plants, withoutnbsp;any remains of Cycadece.

This absence of a predominant antecedent vegetable type in the Dakota formation is not more remarkable than that of other vegetable groups, especially the palms, which constitute an extraordinary large proportion of thenbsp;flora of the Lower Tertiary strata, just above the deep marineformation over-lying or following that of the Dakota group. The section of the Cretaceousnbsp;strata, as copied from Hayden�s Report, page 14, indicates at its base thenbsp;sandstone and clay strata bearing plants, four hundred feet thick, and in ascending, some beds, mostly of clay, of a thickness of seventeen hundred feet, overlaid by five hundred feet of Cretaceous sandstone. Over this formation appears the Lower Tertiary sandstone with fucoidal remains, mixed in its uppernbsp;part with fragments of land-plants, followed by the lignitic formation,nbsp;with its peculiar flora, especially its abundance of palms. The series ofnbsp;strata between the Dakota group and the lignitic Eocene has been uninterrupted, as far as can be judged from the nature of the compound and thenbsp;affinity of fossil animal remains. It does not indicate a period of long duration, at least comparatively to other more complex geological groups; and,nbsp;nevertheless, the flora of the Dakota formation has not a single speciesnbsp;which might be referable to, or is recognized as identical with, any of the

land-plants of the Eocene, especially none of its essential representatives, the Palms. The proportion of Palms, especially of 8abal species is markednbsp;in the lignitic at Golden, Black Butte, amp;c., not only by the remains of leaves,nbsp;which in places fill thick strata of sandy clay, but also by fossil wood of thenbsp;same class of plants, or by their trunks transformed into coal and identified bynbsp;the characters of their internal structure. In ascending from the lowernbsp;lignitic measures, where the essential types of the Cretaceous flora have nonbsp;representatives, we see these Cretaceous types re-appearing, a few in thenbsp;Upper Eocene of Evanston, more of them in the Carbon group above, stillnbsp;more in the Upper Tertiary, following thus an increasing degree of predominance, culminating, it seems, at the present time, in the flora of the easternnbsp;slope of the North American continent. The disconnection of types of thenbsp;flora of the Dakota group appears, therefore, as a kind of break in the vegetable scale, accountable perhaps to modifications of climatic circumstances.

The essential and more numerous vegetable remains in the Dakota group are leaves of Dicotyledonous, representing the three divisions of this class, and,nbsp;what is more remarkable, the genera to which belong most of the livingnbsp;arborescent plants of this country and of our present climate. If what maynbsp;be called positive characters of the genera�the flowers and the fruits�arenbsp;not ascertainable from fossil remains, it is at least impossible to deny thenbsp;intimate relation of most of the leaves of the Dakota group to the genera tonbsp;which they have been referred in their descriptions.

Beginning by the Apetalous, we have, first, Liquidambar leaves, so similar to those of our sweet-gum tree {L. styracijluum) by form and nervation, that, in comparing the fossil leaves with those of our living species, no othernbsp;difference can be remarked but the entire borders of the fossil ones.nbsp;They are more or less serrate-crenulate in the living species, as also in L.nbsp;europeum of the Miocene of Europe. But some species of the same formation, considered by authors as referable to this genus, have leaves with entirenbsp;borders, as seen in the descriptions. Even Gaudin, in his first Memoirenbsp;on the Fossil Leaves of Tuscany, figures as L. europeum, three leaves, onenbsp;of which, with entire borders, (PI. v. Fig. 3,) is remarkably similar to ournbsp;Fig. 1 of PI. ii; the lateral nerves being marked as branches of the secondnbsp;pair of nerves, just as it is in our Cretaceous leaves, and not emerging fromnbsp;the top of the petiole a? in the leaves figured by Heer under the same name.nbsp;Gaudin accounts for the entire borders of this leaf by the suirposition that the

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(lenticulation cannot be remarked on account of the coarseness of the stone imbedding the leaves. We could give the same reason or admit such anbsp;supposition, but the form of the leaves of this genus is so peculiar thatnbsp;the dilference in the more or less serrate borders cannot prevent a genericnbsp;identification. The leaves of the Cretaceous species are, especially bynbsp;their truncate base and their general outline, rather related to those of ournbsp;L. styracifiuu'ni than to those of the Asiatic form, L. ori�ntale. These arenbsp;the two only living species of Liquidamhar with palmately-lobed leaves.

The history of this genus, its origin, and the present distribution of its species, offer, with that of Platanus, a coincidence worth remarking. Bothnbsp;appear first in the Dakota group; both pass through the Tertiary formationsnbsp;of Europe in different modifications; and both have each for essentialnbsp;representatives of the present flora an oriental and an occidental form: innbsp;Asia, Liquidamhar ori�ntale and Platanus orientalis; in our country, L. sty-racifiuum and P. occidentalis, of which the Mexican and the Californiannbsp;forms are mere derivations. No species of Liquidamhar has been as yetnbsp;recognized in our North American Tertiary formations. Two species widelynbsp;distributed are described with numerous varieties from the Tertiary of Europe.

The leaves referred in this memoir to the genus Populites are not comparable to any of the North American species of Populus of our time. They especially differ by the entire borders, which in all our species are morenbsp;or less serrate or dentate. By this character, as well as by their coriaceousnbsp;substance, the relation of the Cretaceous species of Populites is with a peculiarnbsp;group of poplars, the Coriacece, represented in the Upper Miocene of Europe,nbsp;and with us at Evanston and Carbon, by Populus mutahilis and P. gaudini,nbsp;Heer, and at this time by P. euphratica, Oliv., an oriental species, whosenbsp;leaves, however, are dentate, and P. ])ruinosa, Schr., of Siberia, whose leavesnbsp;are nearly round, with borders entire. This last one only may be said tonbsp;have a marked relation to the Populites of the Dakota group.

The relation, however, of Salix and Fagus with present species of our flora is positively marked. Our Salix Candida, Wild., as widely distributednbsp;as a shrub as the beech is as a tree, is the living willow most intimatelynbsp;related to the Cretaceous form. Its type is also represented in the Uppernbsp;Tertiary, or the Pliocene of California especially. The species of Fagus ofnbsp;the Cretaceous is, by its entire, undulate leaves, rather referable to the presentnbsp;F. sylvdtica-'�� Europe than to our F. ferruginea. Both these species, how-

ever, are so similar that they were formerly considered by botanists as mere varieties, and are still admitted as such by some. They have on bothnbsp;continents the same wide and general distribution, being essential constituentsnbsp;of the forests of our present time. Per contra^ most of the species describednbsp;as yet from the Tertiary more or less widely differ from the European or thenbsp;North American types. F. pristina is distantly related to our F. ferruginea.nbsp;F. antipqfi, from the Miocene of Alaska, is related to the same by the slightlynbsp;dentate borders, but differs, indeed, by the larger size of the more taper-pointed leaves. F. macrophylla, of the same formation and country, has thenbsp;leaves entire, like the European species, but still of a far larger size, the specimen figured by Heer representing a leaf sixteen to eighteen centimeters longnbsp;and ten centimeters wide. F. deucalionis, F. feronice, and F. horrida havenbsp;borders of leaves more or less dentate, and therefore more like the Northnbsp;American type. The beech has now representatives in far distant countries, but its types are local, and all the exotic ones differ from that of ournbsp;fossil species. Japan has one species, with leaves cordate at base and borders obtusely crenate, the secondary nerves tending to the sinuses. Chili hasnbsp;five, with leaves obtuse, truncate at the base, and borders mostly doublynbsp;serrate. South Central America has one of very wide distribution;nbsp;it has small, coriaceous dentate leaves. New Zealand has four, all withnbsp;doubly serrate leaves, and the lower surface white, tomentose; and Tasmanianbsp;has for its share two species of a still more distant type, with obtuse^ truncate, and dentate leaves. It is only when out of the geographical limits ofnbsp;the north occidental flora or in the Grecian Archipelago that we find a fossilnbsp;species of Fagus related to an exotic form with doubly dentate small leaves,nbsp;F. dentata, from Eubea, a species which Unger compares to the Chilian F.nbsp;obliqua.

After this we find described, from our Cretaceous flora, Betula heatriciana, comparable, by the form of its leaves and its nervation, to our B. nigra,nbsp;widely distributed from the northern shores of Lake Superior to Florida;nbsp;leaves and seeds of Myrica; at least these which we have figured under thisnbsp;name are undistinguishable from Heer�s seeds of Myrica, described from thenbsp;Cretaceous flora of Quedlinburg, but, indeed, more flattened than the seeds ofnbsp;any of our present species; then two leaves which Saporta considers as representatives of the genus Celtis, of which we have still two species in our flora;nbsp;then leaves of oaks, Quercus yrimordialis, of the type of the so widely distrib-

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uted and variable Q. prinus, the chestnut-oak; and Q. ellswortManus, type of our Q. phellos and Q. imhricaria, species �wdth entire borders of leaves.

It would be hazardous to pursue a typical comparison of the Cretaceous species of oaks on account of the few materials found as representatives ofnbsp;this genus in the shales of the Dakota group. The few specimens referrednbsp;to this genus, however, represent well typified leaves, from which, at least, wenbsp;know that the oaks were already present in the Cretaceous flora of our continent.nbsp;They appear few, in a modest way, though already of two distinct types; but soonnbsp;the forms become more numerous, and the genus takes an important place innbsp;the arborescent vegetation of the world. In the Eocene flora of the Rockynbsp;Mountains, six species have been discovered already, among which one representing the third essential type of our oaks, marked with deeply pinnately-lobed leaves, as in the numerous species of the section of the North Americannbsp;black oaks. The Spring-Canon specimens, which seem to represent twonbsp;horizons of the Tertiary, have eight species ; the Washakie group and Carbonnbsp;have six; and in the Pliocene of California the representatives of this genusnbsp;are still more numerous, and their types still more intimately related to thosenbsp;of the living species. The flora of the California chalk bluffs has six speciesnbsp;of oaks under only thirty-four dicotyledonous species.

The three last genera of the Apetalece. represented in the flora of the Dakota group are Platanus, Laurus, and Sassafras.

Though no fruit of Platanus has been found till now with the leaves, these are, by their form and nervation, positively typified as representatives ofnbsp;this genus. Heer had already recognized P. newherrii in his Phyllites du Nebraska. To this I have added P. heerii, far different from the former, as seennbsp;in the description, and P. primaeva, which, from its likeness to P. acerokles,nbsp;I was formerly induced to consider as a mere variety. Though, from thenbsp;form of its more entire leaves, the Cretaceous species is apparently distinct,nbsp;the analogy or similarity, as indicated by the characters of the leaves, is notnbsp;the less remarkable. It is the type of the species later represented by acutelynbsp;lobed and dentate leaves, which we recognize in the Eocene of the Rockynbsp;Mountains as P. haydenii; in the Miocene of the same country and of Europenbsp;as P. aceroides; in the Pliocene of California as P. dissectus, and especiallynbsp;now as P. occidentalis. P. aceroides was already considered by Europeannbsp;authors as the ancestor of our P. occidentalis before the Cretaceous species

had been discovered. Now we have to refer the origin of onr noble tree to a more ancient epoch.

Like that of Fagus and Liquidamhar, the Cretaceous type of Platanus has not widely varied and multiplied; neither does it appear to havenbsp;changed its habitat in a marked degree, at least not in latitude. One species'nbsp;only, P. aceroides, and its variety, P. guillelmce, is abundantly distributed innbsp;the Miocene of Europe, from Grreenland as far south as North Italy, over annbsp;area of about twenty-six degrees of latitude, while the range of P. occidentalisnbsp;is from the great lakes to the Gulf of Mexico, passing still farther south intonbsp;Mexico'by its analogous P. mexicana. From Europe it has passed eastwardnbsp;as P. orientalis in the same way as it has gone west from our country as represented by P. racemosa of California.

In the LaurinecB we have leaves referable, by their form and nervation, to the genus Lqurus or Persea, and a well-preserved fruit, Laurus macrocarpa,nbsp;which, comparable, also, to the fruits of Cinnamomum and Sassafras, is, fromnbsp;its association in the same localities with leaves of Laurus^ admitted asnbsp;belonging to this genus. It seems a southern type in comparing it to thenbsp;other species of the Dakota gtoup, but it is rather, I think, a shore-type.nbsp;Our Laurus (Persea^ caroliniana extends in following the shores from Virginia to Louisiana and farther west in Texas. It is a meager remnant of anbsp;number of species of the same genus which inhabited our North Americannbsp;continent and that of Europe during the Tertiary period. We find some ofnbsp;them already in our Eocene, especially in Mississippi. Eight species ofnbsp;Laurus and two of Persea have been described from the Miocene of Europe.nbsp;The genus enters by three species into the Miocene flora of the Baltic, but itnbsp;has as yet no representative farther north. None has been described fromnbsp;the arctic regions.

Sassafras belongs to the same family. The leaves of Sassafras are found in such great proportion in the southern area of the Dakota group, especiallynbsp;in Kansas, that the genus seems to have represented there a large part of thenbsp;land-vegetation. Our present S. officinale is, by its leaves, scarcely distinguishable from some of the varieties or forms of the leaves of the Cretaceous species,nbsp;which, like the present one, seems to have had a remarkable disposition tonbsp;variability. I have explained with the description of the fossil leaves whatnbsp;reasons have induced me to separate as species some of the more peculiarnbsp;forms, and to refer all these forms to the'same genus. I must say, however,

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that, considering merely the outlines of the leaves of our present Sassafras, it would be as convenient, if they were found distributed in groups and in anbsp;fossil state, to separate as species as large a number of them as it has beennbsp;done for the Sassafras leaves of the Dakota group.

* One species of Sassafras has been recognized in the more recent geological formations of this continent, the miocene. Three species are described from the Tertiary of Europe, one of which, S. ferretianum, is in the Miocene ofnbsp;Greenland, as also in the same formation of Italy. The wide range of distributionnbsp;of 8. officinale, the only living species, also limited to this continent, is wellnbsp;known. It extends from Canada to Florida, and, over the same latitude, from thenbsp;borders of the Atlantic to the Western prairies, even as far west as the regionnbsp;of the Dakota group, along the banks of the Missouri River near Omaha.nbsp;The distribution of this beautiful, odorant, and sanative shrub, which in goodnbsp;situations becomes a tree of moderate size, is as remarkable as its exclusivenbsp;affection for the land of its origin.^

The division of the Gamopetalece is not as positively and evidently represented in this Cretaceous flora as the former. Heer, however, has described in the Phyllites du Nebraska one species of Andromeda, figured in this memoirnbsp;from better preserved specimens, and one species of Diospiros, to which twonbsp;others have been added from more recent discoveries. The references ofnbsp;leaves of the Dakota group to these genera is therefore reliable. There is innbsp;the Tertiary of Europe and of this continent a number of species of the samenbsp;genera. No less than twenty-four Diospiros species are described from thenbsp;Miocene; among them, two from Alaska and Vancouver Island. Of nearlynbsp;one hundred species known of this genus in the flora of our time, D. virginiana,nbsp;the Persimmon, is the only one which has been left in the temperate regionsnbsp;of the North American continent. None belongs to Europe. Of the two species more intimately allied to the North American, one, D. lotus, a native ofnbsp;China, is often cultivated in the south of Europe; the other, D. kaki, is fromnbsp;Japan; both have eatable fruits.

Proceeding further and coming to the division of the Apetalce, we find among the fossil leaves of the Dakota group an Aralia leaf, similar in itsnbsp;essential characters to one described by Heer from the Cretaceous of Europe.nbsp;There is a slight difference, which may be considered as specific, but generic

1 Like that of our Cornus fiori�a, the acclimatization of this species has not succeeded in foreign countries.

identity is undoubtful; a Hedera, whose affinity is marked by the outline of its coriaceous leaves, and still more by the nervation; three species of Magnolia, represented by a large number of leaves and recognized already in thenbsp;rhyllites by Heer; and four species of Liriodendron, the tulip-tree, whose formnbsp;of leaves, like that of the Sassafras, sufficiently proves the generic reference.

Considering these genera separately in regard to their relations and to their present and past distribution, we find Aralia still represented in -ournbsp;flora by six species, all of different characters of leaves; for, indeed, thenbsp;relation of the fossil form is rather to an old section of the Aralia, with compound palmate leaves, now referred to the Hedera, like H. xalapensis of thenbsp;mountains of Mexico. This type is still represented by large leaves in thenbsp;Pliocene flora of California. H. helix, the ivy to which our Cretaceous speciesnbsp;H. ovalis is closely allied, is indigenous of Europe, where its origin is confirmed by paleontology, the species having been recognized in the Pliocene ofnbsp;Italy. It is, however, of so easy acclimation with us that it looks like an oldnbsp;wanderer returned home after a long absence. In the temperate zone of thenbsp;United States, it invades walls and stone-dwellings as it covers the ruins ofnbsp;the European castles of old. The genus Aralia is not repi'esented as yet innbsp;the fossil Tertiary flora of Europe.

But evidently these two most admirable genera of trees, Magnolia and Liriodendron, belong to North America by origin, succession, and presence.nbsp;Of the eight species of true Magnolia {Magnoliastruiri) now known to botanists, seven belong to the western slope of the temperate zone of North America,nbsp;and the other, M. mexicana, is either a variety of M. glauca or M. grandiflora,nbsp;or even is referable to a different genus. We have seen that already twonbsp;species of Magnolia have been recognized by Heer in the Dakota group. Inbsp;have added one species to the number. In our Tertiary, we have still sevennbsp;species; five of them in the Mississipj)i Eocene, one at Carbon, and one atnbsp;Black Butte. Of the Mississippi species, two have been found in the Eatonnbsp;Mountains, New Mexico, marking thus the genus with the same climatic distribution as it has now, or with wandering representatives far from the limitsnbsp;of its area of general distribution. Thus, one of the species, M. inglefeldi,nbsp;found at Black Butte, is described by Heer from the flora of Glreenland, justnbsp;as we find now groups of M. glauca and M. umbrella isolated in deep gorgesnbsp;in New York, Pennsylvania, etc., far out of the mean range of habitat of the genus.nbsp;In the Pliocene of California, the genus has two species. In the Tertiary for-

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mations of Europe, it has none. As remarked above, however, one species is described from Greenland and two from the Cretaceous formation of Moletin,nbsp;these of a type different from that of the Dakota-group species.

Liriodendron, the tulip-tree, has in its characters, its distribution, and its life a great degree of affinity with Magnolia. The American species is thenbsp;only one known now in the vegetable world, and its habitat is strictly limitednbsp;to this country. It does not ascend higher than the fortieth degree of latitude, except, perhaps, casually, like Magnolia under the protection of favorablenbsp;local circumstances. The genus does not appear to have any disposition tonbsp;modifications of its type and to migrations. We have as yet scarcely anynbsp;fossil remains of it in our Tertiary formations. In that of Europe, it is represented from Greenland to Italy by one species only. The leaves of different forms, described from the Dakota group as four species, may perhaps benbsp;referable to a single one, as the characters, especially the size, of the leavesnbsp;may be local, and result from climatic circumstances. It has thus passed anbsp;solitary life. Even now, by the singular and exclusive form of its pale-greennbsp;glossy leaves; by its large cup-shaped yellow flowers, from which it hasnbsp;received its specific name; by its smooth, exactly cylindrical stem, gracefullynbsp;bearing an oblong pyramidal head of branches, grouped with perfect symmetry, it stands widely apart from the other denizens of our forests as anbsp;beautiful stranger, or rather as a memorial monument of another vegetablenbsp;world. Either considered in its whole or in its separate characters, the Tulip-tree is a universal and constant subject of admiration and wonder. It couldnbsp;be named, not the king, it is not strong enough for that, but the queen of ournbsp;forests, if the Magnolia was not there with it to dispute the prize of perfection by the still grander majesty of its stature, the larger size of its foliage,nbsp;the elegance and the perfume of its flowers. Our sense of admiration fornbsp;these noble trees is heightened still by the dignity of their ancient origin.

I have referred to the family of the Menispermacece, under the generic name of Menispermites^ a large number of leaves related, by their form andnbsp;nervation, to those of the American species of Menispermum, M. canadense^nbsp;and M. carolinum. The relation appears to me as positive as it can be established from a single kind of vegetable organs, the leaves. This relation maynbsp;be searched for in plants of a far distant country and of a different climate,nbsp;and there, perhaps, found as evident with another class of vegetables. But Inbsp;cannot admit that we have to look to foreign types for analogy of a vegetation

whose essential characters are recognized in the species of this country M. canadense is now the consort of our Platanus^ Magnolia^ Tulip-tree, amp;c.nbsp;It grows under the same climatic circumstances, and has the same habitat.nbsp;As the leaves of the Dakota group, compared to this species, are like it�nbsp;peltate, round or cordate, obtusely angular, of the same nervation and consistence�there is reason, indeed, to refer it to this genus rather than to any othernbsp;having no representatives among us.

No species of Menispermum, or Menispermites has been recognized from the geological formations, except the species of the Dakota group. One leaf,nbsp;however, is described by Unger as Acer obtusilobum, which appears to me anbsp;true Menispermites. It has the secondary nervation of Menispermum, {Coc-culus) carolinum, and the basilar veins come out from the borders of a round,nbsp;notched base, as in a peltate leaf. Unger doubtfully considered this leaf as anbsp;species of Acer. Till now, we have not seen any appearance of organs of thisnbsp;last genus, either leaves or seeds, in the Dakota group, as we have none alsonbsp;in the Eocene. The maple seems to be of more recent origin, as it is remarkednbsp;hereafter. However, one Cretaceous leaf, or the fragments of a double leafnbsp;are referred with doubt to the genus Negundo. As the leaf is not complete,nbsp;its outline indefinite, it is useless to argue upon its possible affinity ; and fornbsp;this, as for some others, we have to wait for the discovery of more perfectnbsp;materials.

The relation of other leaves of the Dakota group to the genera Paliurus Rhamnus, Juglans or Rhus, and even Prunus, appears sustained by sufficientnbsp;evidence. The characters of the leaves of Paliurus and Rhamnus are notnbsp;likely to be mistaken. Both these genera have identifiable remains in the Tertiary of the Eocky Mountains ; one Paliurush found in the Eocene of Goldennbsp;and Black Butte, and another in the Miocene of Carbon and Washakie. Thisnbsp;last is an arctic species, also recognized by Heer in the Miocene of Greenland and Spitzbergen. Rhamnus is especially well represented in our Lowernbsp;Tertiary. Eight species are described from Golden, Black Butte, and thenbsp;Raton Mountains, four of which are in the Miocene of Europe, where thenbsp;genus has fourteen species. It is, therefore, an old type, well established atnbsp;the beginning of our Tertiary period f and it is not surprising to find it alreadynbsp;in the Upper Cretaceous flora. Its present distribution is mixed. The genusnbsp;preserves its predominance in Europe by the number of its species; it hasnbsp;there more than a dozen, while in North America it has only four or five.

1 The leaf described under the name of Bhamnus tenax, is considered hy Count Saporta as a Salix.

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It is remarkable that the next closely allied genus, Ceanothus, has not yet been recognized in the Dakota group, though now an exceptional American type. It has one species in the Eocene of Golden, another, very fine, innbsp;the same formation of the Mississippi, and many more in the Upper Tertiarynbsp;of the Eocky Mountains, and especially in the Pliocene of California. Thenbsp;ten living species of true Ceanothus, described in De Candolle�s Prodromus,nbsp;belong to the United States, especially to the southern zone, and a number ofnbsp;them are added to the list by the as yet unpublished flora of California. Thenbsp;absence of the type in the Cretaceous of the West is in accordance with thenbsp;tact remarked upon, in describing the genei'al character of the leaves of thenbsp;Dakota group, viz, the absence in this group of any kind of serrate leaves.

It is uncertain whether the compound leaves, of which a number of separate leaflets have been figured in this memoir as Juglans(%) deheyana, represent a species of Juglans or of Rhus. I should be inclined to refer them to this lastnbsp;genus, especially on account of the nervation more analogous to that of thenbsp;present Rhus metopium of Florida,^ whose leaves also resemble somewhat thenbsp;fossil ones; but there is as yet no sufficient evidence on this account. Innbsp;considering the distribution of the species of both Rhus and Juglans in thenbsp;subsequent formations, we do not find any difference pointing to a predominance of one of these types at any time. From the Dakota group, twonbsp;other kinds of leaves are referable to Rhus. In the Upper Tertiary of thenbsp;Rocky Mountains we have six; and it is well known now that the relation ofnbsp;our vegetable Cretaceous types is not with Eocene species, but rather withnbsp;those of the Upper Tertiary and of the present flora. On another side, Juglans acuminata and J. rugosa, which, by their somewhat coriaceous, entirenbsp;leaves, are distantly related to the Cretaceous species, have been recognizednbsp;at most of the localities where Tertiary fossil plants have been found; theynbsp;are at Carbon and also in the Eocene at Golden, the Raton, Black Butte, amp;c.,nbsp;and thus seem to indicate, by their general distribution, the origin of Juglansnbsp;in the Cretaceous group as evidently as that of Rhus. From the Miocene ofnbsp;Europe, about twelve species of this last genus have been described, two fromnbsp;the arctic regions; and from the same formation, as many species of Juglans,nbsp;with six species of Carya. At our time, J. regia, so generally known andnbsp;cultivated for its large fruit, is of Asiatic origin, while of the other four species

� The specioa is indigenous in Cuba. I have specimens from South Florida, but it may be there cultivated.

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known, three belong to the middle zone of the United States, which has also for its share all the living species of Carya. Of the living species of Rhus,nbsp;Austral Europe has two, one of which, R. cotinus, has been compared, by thenbsp;form of its leaves, to Bumelia emarginata of the Dakota group. We have innbsp;the United States, beside Rhus metopium, which is rather a tropical form, sixnbsp;species of the section of the pinnately-divided leaves, with the trifoliate R.nbsp;toxicodendron and R. aromatica, both extremely variable, all types alreadynbsp;represented in the Pliocene of California.

Except an Amelanchier, described by Dr. Newberry in his Notes on Extinct Floras, amp;c., from the Tertiary beds of the Yellowstone, we do notnbsp;know as yet any fossil species of Rosacecc from the western Tertiary measuresnbsp;This is not a reason why Prunus should be excluded from the list of thenbsp;genera of the Dakota group. By their present distribution, our P. serotinanbsp;and P. virginiana indicate an extreme power of life, or of resistance to climaticnbsp;changes, both being the only arborescent species of this continent having anbsp;range of distribution of thirty to thirty-five degrees in latitude, and both, too,nbsp;being found everywhere, on every kind of ground; the one as a shrub along thenbsp;banks of streams, the other as a fine tree in our woods. And, also, we have innbsp;our P. caroliniana, a shore-tree of the South, a species whose coriaceous, entirenbsp;leaves recall the essential characters of those of the Dakota group. Threenbsp;species of this genus are described from the Tertiary of Europe, and none as yetnbsp;from ours; but it is probable that fossil remains referable to it will be foundnbsp;hereafter, as it has in our present flora a larger number of species than in that ofnbsp;Europe, or of any other part of the world. Of the species described by Denbsp;Candolle, fourteen are North American, five European, four species belongnbsp;to Japan, amp;c.

Resuming, in a few sentences, the above remarks, we find that the dicotyledonous flora of the Dakota group represents species referable to the genera Liquidamhar, Populus, Salix, Betula, Myrica, Celtis, Quercus, (in two of itsnbsp;principal types,) Ficus, Platanus, Laurus, Sassafras, Cinnamomum, Diospiros,nbsp;Aralia, Magnolia, Liriodendron, Menispermum, Negundo or Acerl^), Paliurus,nbsp;Rhus or Juglansi^), and Prunus (T)-, or, merely considering the affinities tonbsp;our present flora, of twenty-one genera, seventeen of which are those to whichnbsp;belong the species of our trees and shrubs which have the more general andnbsp;the widest range of distribution. Indeed, all our essential arborescent typesnbsp;are there, except those which are marked by serrate or doubly serrate leaves:

128

Tilia, JEsculus; all the serrate 7Zo5�ce�; Hamamelis, Fraxinm; the Urticinece, Planera, Ulmus, Moms; and of the Amentacece^ the serrate Betula, Alnus,nbsp;Ostyra, Carpinus^ Corylus, Cary a, amp;e.

This enumeration exposes the general facies of the leaves or of the flora of the Dakota group, viz, integrity of the hoi�ders and coriaceous consistencenbsp;of the leaves. The borders, if not perfectly entire, are merely undulate ornbsp;obtusely lobed. There is only one exception to this in that peculiar shortnbsp;denticulation with outside turned teeth, which is marked, exactly of the samenbsp;kind, in Greviopsis haydenii, Platanus netvherrii, Frotophyllum mudgei, andnbsp;the fragments described as Phyllites hetulcefolius. This mode of division ofnbsp;the borders of leaves is very rare in species of our present times, except,nbsp;perhaps, in some leaves of poplars.^ One species only of the Dakota group,nbsp;Quercus primordialis, has its leaves with borders distantly serrate, ornbsp;marked by teeth turned upward. There is, also, in the flora of the Eocenenbsp;of the Rocky Mountains a marked preponderance of leaves with entirenbsp;borders. The serrate leaves appear in the Miocene with Acer, Alnus, Cory-lus, and become predominant in the Pliocene of California, where Ubnus,nbsp;Planera, Celtis, and Carya abound, though these genera are not recognizednbsp;till now in the flora of the Pacific slope.

But of the detailed correlation of the flora of the Dakota group with that of the subsequent geological epochs of this continent, I will say nothing morenbsp;until the materials on hand are definitely described and figured for comparison.

There is as yet little to say on the relation of the Dakota group flora with that of any of the Cretaceous groups of Europe, especially on account ofnbsp;deficiency of materials for comparison. Of the ferns, Gleicheinia kurriana,nbsp;represented in the Cretaceous of Kansas, is found also in that of Moletin, ofnbsp;Quedlinburg, and even of Belgium, if, as I believe it, Didymososaurus comp-toniifolius is identical with it. Pecopteris nehrascensis, Heer, is closely related tonbsp;Raphd�lia neuropteroides, and Todea (?) saportanea to Monheimia equisgranensis,nbsp;both of the same Belgian formation. In the cycadese (?) and conifers, Ptero-phyllum haydenii has been compared to P. ernestince of the Quadersandst�in �fnbsp;Blankenburg; Sequoia reichenhachi is in the Upper Cretaceous of Greenland;nbsp;and Olyptostrohus gracillimus may be identical with Frenelites reichii of

^ It is, however, remarkably predominant in the leaves of the Lower Eoc ene of Sezane, as also the serrate divisions, as seen in the splendid work of Saporta on the Flore fossile of this formation.

Niedershoena. Among the dicotyledonous vegetable remains, we find seeds of Myrica of the same form as those described by Heer from Quedlinburg;nbsp;leaves of Quercus primordialis related to PhyUites Geinitzianus o� the Quader-sandstein of Silesia; an Aralia and a Protopliyllum, represented by analogous forms in the flora of Moletin; and, in relation to the Cretaceous flora ofnbsp;Niedershoena, there is still to record, Ficus Jialliana compared to F. Geinitzi,nbsp;and Celastrophyllurn ensifolium distantly related to C. lanceolatum.

This is sufficient to prove, relatively to our present knowledge, at least, the truth of tl)e assertion that the flora of the Dakota group, without affinitynbsp;with any preceding vegetable types, without relation to the flora of the Lowernbsp;Tertiary of our country, and with scarcely any forms referable to speciesnbsp;known from coeval formations of Europe, presents in its whole a remarkable,nbsp;and as yet unexplained case of isolation.

After the printing of the last pages of this memoir, I have received, by the kind liberality of the authors, the third and last volume of W. P. Schimpersnbsp;great work on vegetable paleontology,¹ and a very important memoir on thenbsp;fossil plants of Gelinden, (Belgium,) by Count Saporta and Dr. Marion.nbsp;Both tliese volumes expose documents of importance in regard to the Cretaceous floras of Europe, and, by correlation, to that of the Dakota group.

The geological station of the clay-beds bearing plants of Gelinden is referred by the Belgian geologist, Dewalque, to an inferior member of anbsp;group of strata intermediate to the Cretaceous and the Tertiary, or formingnbsp;the lowest division of the Tertiary, under the name of Period Paleocene.fnbsp;This geologist divides this group into the following stages: at the base,nbsp;the Limestone (calcaire) of Mons; above it, the ITeersien system; then, innbsp;ascending, the Landanien, (inferior and superior;) the Ypresien, (inferior andnbsp;superior;) and the Paniselien. The lowest stage, the Limestone of Mons,nbsp;is generally considered as the lowest Tertiary of Europe. Till now, nonbsp;remains of fossil plants have been discovered in it. The Yiiresien correspondsnbsp;to the London clay; the clay-beds of Gelinden are placed in the ITeersiennbsp;system, by the authors of the flora.f

tin Schimper�s Work the Tertiary is divided into five periods: Ist, Paleocene; 2d Eocene-3d, Oligocene; 4th, Miocene; jSth, Pliocene. nbsp;nbsp;nbsp;�

X Essai snr P�tat de la v�g�tation a 1��poqne de marnes heersiennes de Gelinden, by Count Saporta and Dr. A. F. Marion, pp. 8-11.

130

The most abundant vegetable remains of these Lower Tertiary clay-beds represent leaves of Dryophyllum. It has been remarked, in the description ofnbsp;Quercus primordialis of Nebraska, that this species is referable to the same genusnbsp;Dryophyllum established by Devey,in the description of a number of leaves fromnbsp;the Upiier Cretaceous of Belgium. These leaves are considered by the authornbsp;as prototypes of some species of Quercus of the Chamidohalanus section, ofnbsp;Castaneopsis, amp;c., whose representatives, all tropical, inhabit at our time Southnbsp;Asia and the adjoining islands, Borneo, Sumatra, amp;c. In the description ofnbsp;Quercus primordialis I have compared its leaves to those of some varieties ofnbsp;the chestnut-oak, which they closely resemble by their form, their denticula-tion, and their nervation. This relation seemed to me the more admittablenbsp;from the association of the remains of this Cretaceous species with those ofnbsp;others like Fagus, Flatanus, Magnolia, Liriodendron,Salix, Menispermum, amp;c.,nbsp;which are evidently types correlative of a moderate climate. Now, on considering still the great variability of that ancient Dryophyllum, I find in thisnbsp;fact another reason in favor of the relation of its species to oaks of the Lepi-dobalanus section, to which belongs our chestnut-oak. This division has a verynbsp;large number of species ; among others, all the species of Europe and of Northnbsp;America, some of which are endowed with a prodigious power of variability;nbsp;and, also, it is represented in the Lignitic of the Rocky Mountains by othernbsp;species, which, though of different types, as, for example, Quercus angustiloha,nbsp;are positively referable to this same section, mostly represented in the temperate zone.

To the genus Dryophyllum, or to the same type, is also referable Fhyl-lites Geinitzianus, G�pp., from the Quadersanclstem. In the flora of Gelinden, the French authors describe four new species of Dryophyllum, and also figurenbsp;two species of Watelet from the Lower Eocene of the Paris basin, andnbsp;one species, D. cretaceum, Dev., from the Upper Cretaceous beds of Aix.nbsp;Four other species have also been described from Sezane by Saporta. Innbsp;comparing Quercus primordialis to these fossil leaves, its intimate relation isnbsp;recognized especially with Dryophyllum Saportce, Wat., and D. Deimlquei,nbsp;Sap. amp; Mar. It differs essentially from both, however, by its shorter and comparatively more enlarged size and by the absence of cartilaginous or inflatednbsp;borders and teeth. From the remark of the authors of the Flora of Gelinden,nbsp;the sametype re-appears,slightly modified,in Quercusfurcinervis,Rossin.,which,

i�ecognized already in the London clay, ascends to the Lower Miocene of Germany and Italy. In North America, the same species of Quercus has beennbsp;found, in numerous and finely-preserved specimens of leaves, by Prof. Jos.nbsp;Le Conte, under the lava-beds of the Cascade Mountains of Oregon; by Prof.nbsp;J. D. Whitney, in clay-beds of the Spanish Mountains of California; and bynbsp;myseltj in more fragmentary leaves in the Lignitic of Golden. Thus we havenbsp;a series of closely-allied forms of oaks recognized, in the Quader sandsteinnbsp;of Bohemia as PhyUites Geinitzianus; in the Upper Cretaceous of Belgiumnbsp;as Dryoyltyllum cretaceum; in the Nebraska Cretaceous as Quercus primor-dialis; in the Lower Eocene, or Paleocene of France and Belgium in numerous species of the same Dryophyllum; in the Eocene of Europe and in thenbsp;Lignitic of the United States as Quercus furcinerins. Analogous forms of thenbsp;same type are traced farther up in the Miocene of Europe and of America,nbsp;in the Pliocene of California, and at a later epoch in a large number of ournbsp;present species of oaks.

What conclusions can be derived from these facts 1 In regard to the flora of the Dakota group, the re-appearanee in a subsequent period in thenbsp;European Tertiary of one of its types does not modify in the least the remarknbsp;on the disconnection of this flora from the antecedent and next succeedingnbsp;vegetable groups as far as they are known. This genus, Dryophyllum, seemsnbsp;to have had, since its origin, a large, number of representatives, and to havenbsp;been widely, if not universally, distributed. Its presence, therefore, in successive formations, as in different local groups of floras of synchronous stagesnbsp;of the Cretaceous, merely denotes an omnipresent, and, at the same time, anbsp;persistent type, which, like those of Salix, Sassafras, Platanus, amp;c., has passednbsp;through all the geological floras to that of our time with more or less definitenbsp;modifications.

Nevertheless, the flora of Sezane, like that of Gelinden, of the Gyps of Aix, represent, from the Upper Cretaceous to the Upper Eocene, a series of land-formations with vegetable groups, which are absent in the American geology.nbsp;This fact may furnish an argument against the assertion of the as yet unex-jdainable disconnection between the Cretaceous flora of Kansas and Nebraskanbsp;and that of the Lignitic of the Rocky Mountains; for, in the long period ofnbsp;time manifested by these successive and already diversified groups of plants ofnbsp;the Lower European Eocene, the characters of the floras must have been considerably changed, either by introduction of new species or by modifications of

132

types under climatic or any other influence. This is certainly an apparently logical conclusion. But the same groups of floras mentioned above, viz, thosenbsp;of the Paleocene of Europe, contradict by their character�s a supposition ofnbsp;this kind. With the flora of Gelinden that of the Dakota group is relatednbsp;only by that species of Quercus primordialis, or of Dryophyllum, a typenbsp;present, as we have seen, in all the vegetable series of the Upper Cretaceousnbsp;and of the Lower Tertiary, and, with that of Sezane, it has scarcely any othernbsp;relation but that of the same Dryophyllum and of a Sassafras. Consideringnbsp;the general characters of the floras, that of the Dakota group appears stillnbsp;more different from that of Sezane than from that of the American Lignitic;nbsp;for the phsenpgamous species of Sezane are mostly represented by dentatenbsp;or serrate leaves of Betula, Alnus., Myrica, Ulmus, Proto ficus, Populus, Salix,nbsp;Juglanditcs, amp;c., genera either absent in the flora of the Dakota group ornbsp;represented in it by leaves with entire borders, as it has been exjffainednbsp;already.

The European authors have remarked upon the little cohesion of the constitutive elements of the Cretaceous groups of vegetables, which, even whennbsp;apparently synchronous, are so diversified that they appear as brought togethernbsp;at random, and not to have belonged to the same epoch and the same country.nbsp;� Never has the contrast been as great as at that moment, either between thenbsp;floras of next succeeding stages or between those of separate localities, evennbsp;in synchronism, when compared to each other. To quote only the localitiesnbsp;which have been more carefully studied: what point of analytical connection can be established between Niedershoena, in Saxony; Moletin, in Moravia;nbsp;Quedlinburg and Blankenburg, in the Hartz; Halden, in Westphalia; thenbsp;sands of Aix; the Senonien of Bausset; the Santonien of Fuveau, in France;nbsp;and the North American Cretaceous of Nebraska.� *

This remark of Messrs. Saporta and Marion, true as it is and to the point in regard to the vegetable groups of the Cretaceous, might be farther extended,nbsp;as applicable to the succeeding Lower Tertiary floras, which as yet do notnbsp;present any marked degree of homogeneity as far iqi as the Lower Miocene.nbsp;Though it may be, it confirms our remarks on the disconnection of thenbsp;vegetable types of the Dakota group, and also explains the fact, as far as itnbsp;can be, by generalizing it as a correlative phenomenon observed in othernbsp;countries. The same remark amplifies in a degree the probability of truth of

this hypothetical observation, that the first vegetable types, or at least the dicotyledonous ones, have aj)peared, at the same or at diflerent times, not onlynbsp;at different places but witb different original characters, constituting herenbsp;and there distinct groups without homogeneity or relation of forms. Considering what is known of the succession of these groups, it seems as if some ofnbsp;the original types had persisted more or less indefinitely in the series, beingnbsp;modified perhaps by casual circumstances; and as if other original forms ornbsp;prototypes had appeared here and there and multiplied the characters of thenbsp;vegetable groups. Indeed, this second supposition is a mere corollary of thenbsp;former. *

But this touches the question of the origin of species, which cannot be considered now, especially because the materials for the basis of a discussionnbsp;of this kind are as yet too scant. Schimper, in his great work, {Pd�ontologienbsp;wg�tale,') describes, indeed, nearly six thousand species, distributed undernbsp;eight hundred and fifty genera of plants, known from fossil remains of allnbsp;the geological formations. But what is this compared to what is known ofnbsp;the flora of this epoch, of which many hundreds of thousands of species arenbsp;described under more than fourteen thousand genera! Of the old floras,nbsp;especially of those of this continent, we know scarcely a diminutive fraction.nbsp;The task of the paleontologist is, therefore, and must be for a long time (onbsp;come, that of a mere recorder of facts. It is in this point of view that thisnbsp;monography of the plants of the Dakota group has been prepared, and maynbsp;be considered of some advantage to science.

INDEX OF NAMES OF SPECIES AND THEIR SYNONYMS.

136

Page 89, line 1, for Diospyros akcbps, read D. ambigua. Explanation of PL VI, Pig. 6, Diospyros ambigua.

Tlie reader is also requested to make the following corrections on the On PL III (as corrected) for Fig. 1 read Fig. 3.

EXPLANATION OF PLATE I.

EXPLANATION OF PLATE II

EXPLANATION OF PLATE III

EXPLANATION OF PLATE IV.

EXPLANATION OF PLATE V.

EXPLANATION OF PLATE VI.

EXPLANATION OF PLATE VII.

EXPLANATION OF PLATE VIII.

EXPLANATION OF PLATE IX.

EXPLANATION OF PLATE X.

Fig. 1, Laui'us nebiascensis, Lcsqx..................................-.........................

Fig. 2, Laurus macrocarpa, Lesqx..........................-................................... 74

Figs. 3-5, Platanus recurvata, Lesqx............................................................ 71

EXPLANATION OF PLATE XI.

Figs. 1,2, Sassafras (Araliopsis) cretacouiii, Newby..............................-...............

Figs. 3, 4, Sassafras barkerianum, Lesqx........................................................ SI

EXPLANATION OF PLATE XIL

EXPLANATION OF PLATE XIII.

Fig. 1, Sassafras (Araliopsis) cretaceum, var. obtusmii, Lesqx. Figs. 2-4, Sassafras obtnsum, Lesqx.........................

EXPLANATION OF PLATE XIV.

Figs. 1,2, Sassafras acntilobum, sp. uov. Figs. 3,4, Sassafras inudgei, Lesqx.....

EXPLANATION OF PLATE XV.

EXPLANATION OF PLATE XVI.

Fig. 1, Protopliyllmn sternbcrgii, Lesqx.......;................................................ 101

EXPLANATION OF PLATE XVII.

EXPLANATION OF PLATE XVIII.

EXPLANATION OF PLATE XIX.

EXPLANATION OF PLATE XX.

EXPLANATION OF PLATE XXI.

EXPLANATION OF PLATE XXII.

EXPLANATION OF PLATE XXIII.

EXPLANATION OF PLATE XXIV.

EXPLANATION OF PLATE XXV.

Figs. 1,3, Menispermites obtusiloba, sp. nov. Fig. 3, Hedera ovalis, sp. nov...............

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THE FOSSIL FLORA

WESTERN TERRITORIES.

THE CRETACEOUS FLORA.

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ON THE FOSSIL PLANTS OF THE CRETACEOUS DAKOTA GROUP OF THE

UNITED STATES.

10 � 2.�Surface distribution of the Dakota group.

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General section of the Cretaceous rochs of the Northwest.

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124

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128

130

132

INDEX OF NAMES OF SPECIES AND THEIR SYNONYMS.

136

EXPLANATION OF PLATE I.

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EXPLANATION OF PLATE II

EXPLANATION OF PLATE III

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