TER VERKRIJGING VAN DEN GRAAD VAN
DOCTOR IN DE WIS- EN NATUURKUNDE
AAN DE RIJKS-UNIVERSITEIT TE UTRECHT,
OP GEZAG VAN DEN RECTOR-MAGNIFICUS
Dr. C. G. N. DE VOOYS, HOOGLEERAAR IN
DE FACULTEIT DER LETTEREN EN WIJS-
BEGEERTE, VOLGENS BESLUIT VAN DEN
SENAAT DER UNIVERSITEIT TEGEN DE BE-
DENKINGEN VAN DE FACULTEIT DER WIS-
EN NATUURKUNDE TE VERDEDIGEN OP
VRIJDAG 13 JANUARI 1933, DES NAMIDDAGS
TE 4 UUR

Met de voltooiing van dit werk ben ik aan het einde gekomen van mijn
academische studiën.

Wanneer ik op dit tijdstip terugzie op mijn academischen studietijd, dan
grijp ik deze gelegenheid gaarne aan om woorden van dankbaarheid te richten
tot U, Hoogleeraren der Wis- en Natuurkundige Faculteit, voor de wetenschap-
pelijke opleiding, die ik van U mocht ontvangen.

Inzonderheid U, Hooggeleerde Rutten, Hooggeachte Promotor, ben ik
wel in de eerste plaats verplicht voor het onderricht dat gij mij hebt gegeven.
Gedurende mijn ganschen studietijd hebt gij mij steeds met raad en daad terzijde
gestaan en vooral op onze West-Indische reis en bij de uitwerking van het mee-
gebrachte materiaal in Utrecht heb ik ervaren welk een voorrecht het is geologie
te studeeren aan de Utrechtsche Universiteit.

Hooggeleerde Schmutzer, ik kan het slechts betreuren niet gedurende
mijn geheele studietijd van Uw kennis en inzicht te hebben kunnen i)rofiteeren.
Ik waardeer in hooge mate het geduld waarmee gij mijn gesteenten hebt
doorgezien en de waardevolle aanwijzingen die gij mij vaak hebt kunnen geven.

Hooggeleerde Brouwer, Uw avondcolleges in de tectonische geologie, met
zooveel enthusiasme gegeven, hebben mijn belangstelling in de geologie in niet
geringe mate doen toenemen.

Hooggeleerde :\\Iohr, Uw colleges in bodemkunde hebben mij ingewijd in
een vak, nauw verwant met de geologie en hoewel van niet te onderschatten
belang voor de geologie, toch doorgaans zeer veronachtzaamd door geologen.
Het verheugt mij in de gelegenheid geweest te zijn, eenigen tijd onder Uw leiding
practisch te werken.

Hooggeleerde Nierstrasz, ik zal het steeds als een groot voorrecht blijven
beschouwen, mijn zoölogische opleiding van U te liebben mogen ontvangen.
De origineele en bezielende geest die van Uw colleges en van den omgang met U
uitgaat, zal mij voortdurend bijblijven.

Hooggeleerde Went en Pulle, in mijn schooltijd is de botanie jarenlang
mijn lievelingsvak geweest. Ik dank U dat ik onder Uw leiding mijn kennis in
deze richting heb kunnen uitbreiden.

Hooggeleerde Van Dam, de Spaansche taal lag buiten mijn oorspronkelijke
studiekring, maar niet buiten de kring van mijn belangstelling, toen ik er door
de omstandigheden mee in aanraking was gekomen. Belangstelling alleen was
echter niet voldoende, een vereischte was volharding van mijn kant, geduld van
Uw kant. Voor de moeite die U zich voor mij gegeven heeft en het geduld dat
U met mij gehad heeft, zal ik U steeds erkentelijk zijn.

Description of the rocks of the Washikemba formation .nbsp;10
Correlation of the Washikemba formation with rocks

In the summer of 1930 Prof. L. Rutten, his wife and six students, among
whom the author of this paper himself, made a journey to the West Indies. The
main object was to make geological researches on the islands of Curagao, Aruba
and Bonaire. From the 10th of May to the 10th of June we spent our time on
Bonaire. An idea of the closeness with which our observations were made on the
island can be got from the accompanying map showing points where and routes
along which observations have been made (fig. 1). The basis for our geological
fieldwork furnished the topographical map 1:20.000.

Before 1930 geological fieldwork was done on Bonaire by Prof. K. Martin,
viz. in 1885. Although Prof. Martin could spend only four days on the island,
he succeeded in composing a rough scheme of its geology (lit. 27). He found
quaternary limestones, cretaceous sediments (cherts and sandstones — the
latter rocks are coarse tuffs), diabases, porphyrites and tuffs, but he did not
notice the relation between the quot;Cretaceousquot; and the volcanic rocks.

The rocks collected by Martin were described by J. H. Kloos in 1887 (lit.
23), his fossils by T. W. Vaughan (corals, 1901, lit. 65) and I. Lorie (mollusks,
1887, lit. 68).

Afterwards collections of rocks (and some fossils) have been made on Bo-
naire by Dr. I. Boldingh (1910), by Ir. G. Duyfjes (1911?) and by Prof. J. A.
Grutteiunk. Never was anything published about these rocks. Dr. Boldingh
gave a sort of pedological map (lit. 3), in which the boundaries of the Creta-
ceous in E. Bonaire (called by him quot;non calcareous soilquot;) were roughly drawn,
but already with more accuracy than on Martin\'s map.

Boldingh\'s collection is in the Mineralogisch Geologisch Instituut of the
State University of Utrecht, those of Duyfjes and Grutterink are in the Insti-
tuut voor Mijnbouwkunde of the Delft Technical University. I have taken the
rocks of Boldingh, Duyfjes and Grutterink also into account and have
revised the rocks of Martin, described by Kloos. The collection of Martin is
in the Rijksmuseum van Geologic en Mineralogie at Leiden. The rocks of Martin
mentioned in the text are indicated with quot;Maquot;, followed by the number originally
given by Martin, under which number the rocks are described by Kloos. Our
own collection is in the Mineralogisch Geologisch Instituut at Utrecht; the rock
samples of Bonaire are indicated with the letter quot;Bquot;: B. 1, B. 2, etc.; theslide
numbers are indicated with quot;D.quot; Our annotations and our maps used on Bonaire
with the numbers corresponding with the annotations are kept in the Mineralo-
gisch Geologisch Instituut at Utrecht.

In my descriptions I have used some words of Papiamento, used on the
topographical map:

Boca, bay; Seroe, hill; Rooi, plural Rooi en (derived from the Spanish arroyo),
river beds only carrying water in the rainy season.

Some geographical names are used both in E. and W. Bonaire. They are:
Seroe Grandi, Seroe Largoe, Seroe Montagne, Punta Blanco. When used in the
text these names are followed always by E., resp. W. Bonaire.

which is of much interest in view of the great many American geologists and
paleontologists who make researches in the West Indies.

I wish to express my sincere thanks to many who, directly or indirectly,
have rendered assistance to me during our journey to the West Indies or during
the examination of the material in Holland:

In the first place I owe many thanks to my fellow-travellers to the West Indies:

Prof. Dr. L. M. R. Rutten, the leader of our excursion to the West Indies
and my scientific quot;leaderquot; in the full sense of the word during my years of geolo-
gical study at the University of Utrecht:

Mrs. Dr. C. J. Rutten-Pekelharing, who accompanied us to the West
Indies and shared all the minor and greater difficulties of the journey.

My fellow-students J. H. Westermann, L. W. J. Vermunt, H. J. Mac
Gillavry, M. G. Rutten and P. Wagenaar Hummelinck. The agreable inter-
course with them during aur journey to the West Indies and throughout my
college years will for ever remain in my remembrance.

To the C. P. I. M. (Cura9aosche Petroleum Industrie Maatschappij), and
especially to Ir. C. van der Stok for their assistance lent on Curasao with
disembarking and embarking, with accomodation, with travelling and camping
on Curafao, etc., etc.

To Mr. B. van Slobbe, Governer of Curagao, for placing at our disposal a
torpedo-boat destroyer in order to take us across from Curasao to Bonaire
and vice versa and for allowing us to make use of the quot;pasanggrahanquot; at
Kralendijk.

To Messrs. E. Vreede, officer in command on the Witte de With, and
H. Nieuwenhuis, officer in command on the Van Galen, for their cordiality
during our crossing.

To Mr. H. B. C. Schotborgii, Commander of Bonaire, and to Mrs. Sciiot-
borgh for their kind assistance and hospitality on Bonaire.

To Prof. H. Gerth, of Amsterdam, for his assistance provided in deter-
mining the corals.

To the Bataafsche Petroleum Maatschappij, at the Hague, for placing at my
disposal their index-system with figures of foraminifera.

To Dr. H. E. Thalmann, who placed at my disposal his index-system and
literature of foraminifera and who has been of the greatest help to me with the
determination of the smaller foraminifera.

To Dr. R. Koch, who rendered me several good services in connection with
my paleontological examinations.

To the Rijks Museum voor Geologie en Mineralogie at Leiden for placing
at my disposal the collection of West Indian rocks and fossils of Prof. Martin.

To Prof. Ir. J. A. Grutterink, of Delft, for placing at my disposal his
collection of Bonaire rocks.

To Dr. Cii. Bayer, Curator at \'s Rijksmuseum van Natuurlijke Historie at
Leiden, for his assistance with the determination of Bonaire moUusks.

To Dr. C. T. Trechmann for his valuable informations concerning some
mollusks from Curasao and Bonaire.

To the staff of the Geologisch Mineralogisch Instituut at Utrecht: Mr. J. van
Dijk for the manufacturing of the photographs and the geological map; Messrs.
J. Grootveld and J. Verheer for the manufacturing of the thin sections.

To Mrs. J. van Ginkel-Koppejan and Mr. Hoogesteger, my brother-in-
law, for the revision of the English text.

In conclusion to many in the West Indies and in Holland, who have supplied
me with informations or who have been of assistance to me.

Topographically the isle of Bonaire can be divided into two distinct parts:
a NW.—SE. running part and a N.—S. running part. The NW.—SE. running
part is higher and largely dissected by numerous quot;rooienquot;. It consists of nume-
rous small hills (quot;Seroe\'squot;), generally with gentle slopes; the highest hill is the
Seroe Brandaris (240 m.).

The NW.—SE. running part contains the older, prae-quaternary forma-
tions of the island. Large areas of it, however, are taken up by quaternary
limestone. The N.—S. running part is very low and flat; it is entirely built up
of quaternary limestone and alluvial deposits (detritus of the oldest formation,
coral sands, coral shingle).

The oldest deposits of the island are of volcanic origin: they are lavas and
tutls, mainly of diabase and porphyrite, with intercalations of cherts and lime-
stones. The greater part of the hills is built up of these rocks. We called the
formation quot;Washikemba formationquot; after the Washikemba Plantation, where
this formation was found one of the first days of our stay on the island. It is
almost certain that the Washikemba formation is of upper cretaceous age.
l^hroughout the formation intrusions occur (necks, dikes and sills) of porphyrite
and diabase, petrographically belonging to the Washikemba formation. A more
detailed description of it will be given in Chapter II.

At one place in the Washikemba formation (W. of Seroe Grita Kabai, W.
Bonaire) an intrusion of a porphyritic diorite lias been found (see Chapter III).

Younger than the Washikemba formation, but still Cretaceous, is a series
of limestones, conglomeratic limestones and conglomerates found exclusively
in the surroundings of the village of Rincon (W., NE. and SW. of Rincon). We
called it the quot;Rincon formationquot;. It lies unconformably upon the Washikemba
formation. Remarkable is the occurrence of pebbles of foreign rocks in the
Rincon formation, being granodiorites and granodiorite aplites (see Chapter IV).

A conglomerate which is a little younger than the Rincon formation shows
a great increase of foreign pebbles. The pebbles are more numerous, generally
of larger size and besides granodiorites and granodiorite aplites there occur
gneisses, quartzites and some other foreign rocks. After its occurrence near to
the Soebi Blanco the conglomerate has been called the quot;Soebi Blanco conglo-
meratequot; (Chapter V).

many fossils have been found in them, chiefly echini and foraminifera. A fora-
minifera marl, which yielded a rich fauna of smaller foraminifera was found in
a well near Porta Spano (Columbia Plantation). Upper eocene limestones occur
SW. of the Seroe Montagne (W.Bonaire), near to Punta Blanco (cirque of Rincon),
in the Columbia Plantation between Fontein and Moreke and NW. of Terra
hoendoe (Chapter VI).

As has been mentioned before large areas of the NW.—SE. running part
of the island are covered with quaternary limestones, partly encircling the older
formations. Like the low N.—S. running part, the islet Klein Bonaire is entirely
built up of quaternary limestones. In Chapter VII more will be found about
the Quaternary of Bonaire.

Among the rocks of the Washikemba formation can be distinguished:
diabases, diabase porphyrites, amygdaloidal diabases, amygdaloidal diabase
porphyrites, quartz bearing diabases and quartz diabases, amygdaloidal quartz
bearing and quartz diabases, quartz bearing diabase porphyrites, porphyrites,
quartz bearing porphyrites and quartz porphyrites, mica bearing porphyrite(s),
mica bearing quartz porphyrite(s), amygdaloidal porphyrites (s.l.), porphyries,
diabase crystal tuffs, diabase tuffs, crystal tuffs, porphyrite crystal tuffs, quartz
bearing porphyrite crystal tuffs and quartz porphyrite crystal tuffs, porphy-
rite tuffs, quartz bearing porphyrite tuffs and quartz porphyrite tuffs, diabase
breccias, porphyrite breccias, cherts, radiolarites, jaspers, jasper breccias, lime-
stones. There were, besides, found a conglomerate and a pebble of a pyroxene
porphyrite.

In this chapter the names quot;diabasequot;, quot;porphyritequot;, quot;diabase tuffquot; and
quot;porphyrite tuffquot; will be used in sensu lato. Thus quot;diabasequot; stands for diabases,
diabase porphyrites, amygdaloidal diabases, etc.; quot;diabase tuffquot; stands for
diabase crystal tuffs and diabase tuffs; etc.

The strike of the Washikemba formation is predominantly NW.—SE.,
especially in the W. part ot the formation. The strike N. 130 E. is the most
frequent.

Some strikes in the E. part, which diverge strongly from the NW.—SE.
direction and which we find especially in a region W. and SW. of the Washikem-
ba Plantation, run principally N. 160 E. to N.—S. The Washikemba rocks
exhibit an almost monoclinal dip to the N.E., with an average of 35°—40°.
Dips to the SW. are very exceptional, in W. Bonaire they form 3,1% of the
dips measured (227), in E. Bonaire 3,4 % (of a total of 116 dips measured).

The distribution oi the Washikemba rocks is as follows. There occurs a wide
zone of diabases and diabase tuffs in the lower part of the formation. Here and
there cherts are intercalated among these rocks and in places some porphyrites
and porphyrite tuffs appear. Exposures of diabases and diabase tuffs are found
everywhere between Terra hoendoe and Lamoenchi (E. Bonaire) and W. of
Goto (W. Bonaire).

Higher up in the Washikemba formation the situation in E. and W. Bonaire
becomes different. The large cirque of Rincon will be considered apart, it differs
from both regions. We will first treat W. Bonaire.

diabase tuffs decrease gradually, they pass into porphyrites and porphyrite
tuffs. In the highest part of the formation, in the flat coastal plain near the NE
of the Seroe Mangel, Seroe Soempina and Seroe Caracao, and in the southeastern
continuation of this coastal plain, diabasic rocks appear again in abundance.

In E. Bonaire the distribution of diabases and porphyrites NE. of the zone
of diabasic rocks is much more irregular. Porphyrites and porphyrite tuffs are
most common here, but in several places large areas with outcrops of diabase
are found, e.g. NE. of the Seroe Grandi (E. Bonaire), N. and NW. of the Washi-
kemba Plantation and E. of the Seroe Barra di Carta.

In the large cirque of Rincon outcrops are rather scarce. The outcrops that
were found, chiefly consist of diabase. Consequently it is most likely that the
whole region predominantly consists of diabasic rocks, all the more likely as
diabase is less able to resist erosion than porphyrite.

Cherts, though occurring throughout the Washikemba formation, are most
numerous in the higher parts.

Fine exposures of cherts occur NE. of Boca Bartool, in the Rooi Grandi
and N. of Rincon; a very fine complex of various tuffs, alternating with cherts,
was found in the Rooi Camia.

The limestones occur here and there among the other rocks, in thin beds,
which seldom exceed 1 dm. No definite distribution can be given. It is possible
that the limestones are more numerous in the higher than in the lower parts
of the formation.

By the re-appearance of diabases in the highest part of the Washikemba
formation in W. Bonaire one could get the impression that isoclinal folding
had taken place. But this is, certainly, not the case. The zone of porphyrite is
quite asymmetrical: in the lower part there is a gradual transition from the
zone of preponderating diabases and diabase tuffs into the zone of porphyrites
and porphyrite tuffs. This transition cannot be observed in the higher part.
Cherts are much more abundant in the higher than in the lower part of the
porphyrite zone.

In the zone between that of predominating diabases and diabase tuffs
and that of predominating porphyrites and porphyrite tuffs, the different rocks
often alternate at short distances. This can be clearly illustrated by the following
section , surveyed in the E. of Boca Slagbaai.

b. ca. 7 m.nbsp;diabase breccia, with large enclosures of diabase and amygdaloidal diabase,
diabases, with enclosures of tuff.

bed of diabase, weathering with ellipsoidal structure,
d. 1,25 m. ? silicified tuffs,
c. 20 m.nbsp;diabases or diabase tuffs,

Diabases, weathering with ellipsoidal structure, can often be observed on
Bonaire. In this feature the Bonaire diabases differ from the Curasao and Aruba
ones. Martin too was struck by this difference. On p. 74 of his geological descrip-
tion of Bonaire (lit. 27) he writes: „.. . einen niedrigen, aus kleinkörnigem Diabas
gebildeten Hügel, dessen Gestein in grosse, sphaeroidische Blöcke zerfallen ist.
Diese Verwitterungsform findet sich überhaupt auf Bonaire weit häufiger als
auf den beiden anderen Inseln. . .quot;. Martin ascribes this difference in
weathering to a difference in the structure of the diabases of the three islands:
„. . . denn sie (viz. weathering with spheroidal structure) ist nur dem körnigen
Diabase eigen, der auf Bonaire fast ausschliesslich vorkommt, während auf
Curasao und Aruba dichte Varietäten vorherrschenquot;.

The porphyrites often show columnar jointing, this may be observed with
several porphyrite outcrops, e.g. the Seroe Brandaris and the Seroe Kibra
Guarati.

The Washikemba formation reaches an enormous thickness, which we must
fix, at all events so far as W. Bonaire is concerned, at 5000 m. at the least. This
seems to be very much and one would expect that a considerable time was
necessary for its deposition. But one should not forget that the greater part of
the rocks of the Washikemba formation are of volcanic origin. Lava flows often
get a considerable thickness, and a complex of tuffs can be deposited in a much
shorter time than e.g. a complex of shales or marine sands of the same thickness.
Non-volcanic rocks are rather scarce in the Washikemba formation. A part
or all of the cherts may be silicified tuffs, only the limestones are doubtless
non-volcanic. Consequently we see that thousands of meters of rocks in the
Washikemba formation are purely volcanic.

We may declare almost with certainty that the Washikemba formation
is of cretaceous age. In the highest parts of the formation, S. of the Seroe
Ventana (W. Bonaire), was found a coarse grained conglomerate. This conglo-
merate contains pebbles of Washikemba rocks in a calcareous matrix. The
pebbles consist of diabase, porphyrite, tuff, and porphyritic rock fragments
with chloritized and silicified matrix and crystals of feldspar. In this conglo-
merate were found two rounded corals, MuUicolumnastraea farvula Gerth and
Actinacis martiniana d\'Orbigny. MuUicolumnastraea parvula is know from Cura-
9ao, where it was found by G. J. H. Molengraaff in the Seroe Teintje limestone.

Actinacis martiniana comes from the Upper Cretaceous of Gösau. Consequently
the corals point to Upper Cretaceous. The conglomerate must be younger than
the corals that occur in it. But the difference in age between the corals and
the conglomerate may be very slight, because corals, occurring in a marine
conglomerate, may have been broken from a living reef by the surf, which
formed the conglomerate. Thus we can be sure that the conglomerate is Upper
Cretaceous. This would indicate an upper cretaceous or cretaceous age for the
Washikemba formation, if the conglomerate belongs to it. Though personally
am I convinced that it really does, it will be good just to face this question.

The following data, are at our disposal. The coastal region, where the
conglomerate was found, is flat and arid, and exposures are scarce and bad
there. As a result of this the connection between the conglomerate and the
other Washikemba rocks (these being principally diabases here) is not clearly
visible. Like the surrounding rocks, the conglomerate lies under the quaternary
basal conglomaratic limestones of the Seroe Ventana, by which it is uncon-
formably covered. Approximately the conglomerate has the ordinary NW._

SE. strike of the Washikemba formation. Southwestward as well as north-
eastward of the conglomerate there appear weathered diabases and waste
of diabase rocks. The conglomerate was also found SE. and E. of the Seroe Mei
Mei, bordered by diabase breccias, diabase tuffs and porphyrite tuffs (tuffs:
N. 120—130 E.; 25° NE.). If the conglomerate does not belong to the Washikemba
formation, it must lie on the Washikemba rocks with an angular unconformity,
but with equal strike. The question can only be solved, when dips can be mea-
sured of the conglomerate and of the rocks in the immediate neighbourhood.
In my opinion there can be little doubt that the conglomerate belongs to the
Washikemba formation, however, I do not wish to reject the possibility that it
does not belong to it.

There will be given a regional geological argument in support of the creta-
ceous age of the Washikemba formation when discussing the correlation of the
Washikemba rocks with rocks of adjacent regions.

In the field the diabases are generally strongly weathered rocks, often showing sphe-
roidal structure. If not weathered, the rocks are dark green to grey, in some cases bluish
grey to nearly black; weathering changes the colour into dirty brown, greyish brown or dirty
green. The diabases are medium to fine grained; in the medium grained diabases crystals of
feldspar, occasionally of ferro-magnesium minerals and ore, can be recognized with the
naked eye. The dimensions of the crystals in these diabases are up to or slightly exceed
1,5 mm.; the average dimension is 0,8 mm. The diabases are holocrystalline, and generally
they show a typical ophitic structure. There are no indications that glass is ever present.

The principle constituents are feldspar, pyroxene, and ore (magnetite); other occurring
minerals are apatite, ilmenite, haematite, chlorite, quartz, uralite, limonite, calcite, epidote,
sericite. The occurrence of some dust among these minerals is not rare.

Feldspar. Plagioclase, varying from labrador to albite; most common are albite and
albite oligoclase; labrador and even ande-sine are very rare. The composition of the feldspars

has been defined by means of a refraction index. The predominance of acid plagioclase
is due to albitization, a diminution of the basicity of the feldspars. We cannot assume that
these rocks, with, their quite typical diabase structure, originally contained acid plagioclase.
It is worth, mentioning that in one rock sample labrador and andesine as well as oligoclase
and albite can occur at the same time. Sometimes the crystals are dusty-stained; then
the dustiest spots have the lowest refraction index, consequently corresponding with the
strongest albitization, and conversely.

In most cases feldspar is lath shaped, big crystals are often prismoid, small ones-occa-
sionally xenomorphic. Almost all the feldspar crystals show poly^ynthetic twin structure,
zonal structure is occasionally present. Nearly without exception the feldspar crystals are
dusty and they have not seldom greatly decomposed, then containing chlorite and occasio-
nally sericite, quartz and epidote. In some cases the feldspar is permeated with a clear,
colourless or cream coloured zeolitic mineral. In some sections the feldspar laths are provided
with a central tubular cavity, which cavity runs through the whole crystal (as is clear to
see in longitudinal sections of the laths). The nature of the material with which the central
cavity is filled, cannot be verified, because it has entirely changed into chlorite and limonite.

Pyroxene. It is a monoclinic, diopsidic pyroxene, generally colourless; if coloured,
very pale violet, pale yellow or pale green. Remarkable in this pyroxene is the great disper-
sion of the optic axes for different wave lengths. In polarized light extinction can hardly,
if at all, be obtained; in the latter case the extinction does not go farther than a very dark
green or deep blue. The appearance of the pyroxene is generally fresh and transparant,
sometimes with dull shades. Pleochroism, in connection with the light colouring, is wanting
or very weak. As to the cleavage, the common system of interrupted cleavage cracks,
crossing one another at nearly right angles is only rarely developed; in most cases one can
observe merely strong, very irregular cracks. Twinning occurs only exceptionally. The
dimensions of the pyroxene crystals are on the whole smaller than those of the plagioclase;
idiomorphism is less common and less pronounced. In many diabases the pyroxene is
merely xenomorphic; when idiomorphic, it is prismoid.

The pyroxene can have greatly altered, mostly into green chlorite, whether or not accom-
panied by quartz and limonite; here and there alteration into epidote or sericite has taken
place.

The quantitative proportion of feldspar and pyroxene is difficult to define. Without
doubt it is varying; there are diabases in which the percentage of feldspar and of pyroxene
is about equal, and there are diabases in which feldspar is positively dominating. But most
of the diabases contain a certain quantity of secondary minerals, especially chlorite, and it
is. possible and even probable that in these diabases the ferro-magnesium minerals have
been greatly replaced by the secondary minerals, so that a clear view of the proportion
between the quantities of feldspar and pyroxene cannot be obtained any longer. In a few \'
diabases pyroxene is lacking; seeing, however, that all these diabases contain a large quantity
of secondary minerals, it is most likely that the pyroxene in them has been entirely altered.

Mica. This mineral was found in some diabases. We can distinguish biotite, discoloured,
generally occurring together with pyroxene and being of the same date, and fine scales
of fibrous sericite. The presence of mica in the diabases is very exceptional. The sericite
is probably secondary.

Magnetite. It occurs in nearly all diabases, generally in numerous small grains, regularly
scattered over the rocks. Magnetite crystals of larger dimensions are less numerous, occurring
in square, rectangular and parallelopipedic sections or irregularly shaped; as an exception
ore skeletons and needles occur. The magnetite has often changed into limonite. Sometimes
it is titanium bearing — titano magnetite — and has partly changed into titanite and
leukoxene. The amount of titanite and leukoxene is never large; at the most some crystals
of strongly refracting titanite, bordering on the magnetite, or an incomplete rim of white
flaky leukoxene aggregates are to be seen.

The amount of magnetite in the diabases is very variable. As has been stated, nearly
all diabases contain magnetite in larger or smaller quantities, but there are diabases in which

magnetite is entirely wanting, others in which the eventual presence of it is only indicated
by some very sparse particles of limonite.nbsp;^ maicatea

7/mmzfe This has been found in only one of the diabases (B. 55, D. 12082), in numerous
big and small grams, of an irregular idiomorphic shape.

nee^eToiorenbsp;^^^\'quot;^tite is represented in some diabases by several small limonitized

Apatite. In a few diabases it appears like small needles which are locally numerous
and also as an enclosure in the feldspar.

Chlorite. Green to nearly colourless, mostly light green, occasionally light brown yello-
wish brown, greenish brown to brown, probably because of an addition of limonite In
genera the chlorite is fibrous, often spherolitic. Pleochroism feeble or wanting- birefringence
generally low in some cases relatively high. Abnormal interference colours (blue) are rare
The optical character of elongation (in sections approximately perpendicular to the acute
bisectrix) is nearly always positive, always with the green varieties. Most likely this green
chlorite IS delessite, a chlorite, which is very common in the diabases of Curacao too The
brown colours may be due to limonite.

The chlorite is very abundant in most of the diabases; it occurs in the feldspar and in

the pyroxene and as irregularly shaped aggregates among these minerals, especially among

the feldspar rods. In the latter case it may have been derived from the pyroxene in a large
Gxtcnt.nbsp;®

Epidote. Ordinary epidote (pistacite): colourless to light green, if coloured, pleochroitic
Birefringence high. Generally it occurs in small grains, as secondary mineral in the pyroxenequot;
and in places among the other secondary products.

Quartz. Quartz can occur in fine grained aggregates among the other secondaries
especially among the chlorite. Bubbles of liquid matter can often be observed

These rocks differ in one respect from the diabases, viz. the presence of phenocrysts
of feldspar, sometimes of feldspar and pyroxene. The constitution of the feldspar in the
diabase porphyrites does not differ from that in the diabases. The feldspar phenocrysts
are in general ess modified than the feldspar of the matrix. The pyroxene is the same diopsidic
pyroxene that occurs m the diabases. The feldspar phenocrysts are developed into prismoid
crysta s, the dimensions of which seldom exceed 2 mm. The pyroxene phenocrysts never
reach the dimensions of the feldspar phenocrysts. The quantity of phenocrysts in the diabase
porphyrites is never very large. The matrix is holocrystalline; it has the ophitic structure
as we know from the diabases. In a part of the diabase porphyrites the matrix is finer
grained than in the diabases. The fact that feldspar predominates to a great extent in the
phenocrysts of the diabase porphyrites, is again a result of the riches of feldspar of these
rocks, a phenomenon that we can observe in all the Washikemba rocks.

In some very weathered diabase porphyrites the phenocrysts have entirely or almost
entirely changed into a granular or fibrous aggregate of chlorite or, more rarely of calcite
sometimes together with quartz, in such a manner that nothing but the shape of tlie crystal
IS recognizable. Some of the feklspar phenocrysts can give us an idea how the albitization
may have taken place. Without crossing the niçois we see one idiomorphic crystal- when
we cross the niçois the crystal falls apart into numerous irregularly shaped feldspar aggre-
gates with different orientation. In other phenocrysts the modification is not so far advanced
so that a part of the original crystal has been preserved, though greatly decalcified

Enclosures in the feklspar phenocrysts are rare; if present, they are granules of magnetite;
m one diabase porphyrite enclosures of pyroxene were found in the feldspar phenocrvsts.
.w few diabase porphyrites silicification of the matrix has taken place, a phenomenon
tnat we shall meet with on a much larger scale among the tuffs.

Diabases and diabase porphyrites have been treated here separately; it is obvious
however, that we cannot draw a sharp line of demarcation. Apart from typical diabases
and typical diabase porphyrites, there are diabasic rocks with crystals of different dimensions
varymg from the dimensions of phenocrysts to those of the matrix. Those rocks, not showing
two distinct generations of crystal growth, have been invariably placed with the diabases
Anyhow, diabases are far more numerous than diabase porphyrites.

The amygdaloidal diabases distinguish themselves from the diabases by the occurrence
of amygdales. Number, size, shape and filling of these amygdales vary in a large measure.
The dimensions can exceed 1 cm. As constituent parts of the amygdales occur quartz
chlorite, calcite, chalcedony, zeolitic minerals, prehnite, feldspar, ? epidote. Amygdales
with quartz, chlorite, calcite and with quartz and chlorite are most frequent. The quartz
is generally not very fine grained and provided with a spherolitic, fine grained, often dusty
rim. In some cases the spherolitic rim is composed of chalcedony. Bubbles of liquid matter,
possibly gas bubbles too, are not unusual. The chlorite is generally fibrous or spherolitic;
it does not differ from the chlorite that, for the rest, is found in the diabases as an altera-
tion product of the different constituents.

In one amygdaloidal diabase (B 60, D. 12087) occur vesicles provided with feldspar.
As this rock will be discussed later on, tlus occurrence will be treated in that place (p. 25)^

Calcite too was frequently observed in amygdales. It appears in big crystals, to some
extent pan-idiomorphic, or fine grained fibrous to spherolitic or granular. Beside the occur-
rence in amygdales, calcite is often present as an impregnation in the diabasic rocks. The
zeolitic minerals form small fibres or grains of fresh crystals. Generally they have a high
refraction index and varying, birefringence, which is generally low, sometimes abnormal.

Two amygdaloidal diabases (B. 81, D. 12108 and B. 82, D. 12109; localities: Guatemala
Plantation, resp. N. of Deenterra) contain clinozoisito (not in the vesicles), in long prismoid
to lath shaped crystals, with well developed crossways running cracks. The colour of this
clinozoisite is brownish violet, the pleochroism is very feeble or failing, the birefrin\'^ence
low, maximal extinction 35 degrees.

As the characters of these rocks do not differ from those of the diabase porphyrites, or of
the amygdaloidal diabases respectively, I need not say anything more about them petrogra-
phically. As far as their frequency is concerned, they can be compared with the diabase
porphyrites; like the latter they are, among the diabasic rocks, in the minority.

These diabases are quite comparable with the other diabases except for a certain
quantity of primary quartz being present. We have little evidence as to the nature of this
quartz. I feel justified in considering the quartz as a primary constituent in these diabases
for the following reasons:

1. The quartz is very regularly spread among the other components. 2 There are no
direct evidences that the quartz is of secondary origin. Among such evidences I reckon a
certain connection or co-ordination or an interweaving of quartz and unquestionable secon-
dary minerals (e.g. chlorite), among such evidences I also reckon a replacement of certain
minerals bij quartz. 3. The quartz, xenomorphic, is always pressed in the interstices
of the uliomorphic or hypidiomorphic feldspar. The impression one gets is that the (luartz
crystallized out of a residual liquor, filling all the existing room.

Besides primary (juartz these diabases can contain some secondary quartz. One of
the quartz diabases is amygdaloid.

Seeing that these rocks combine the characters of both diabase porphyrites and quartz
diabases it suffices to mention the occurrence of one quartz bearing diabase porphyrite
on Bonaire (B. 68, D. 12095; W. of Goto).

Martin collected some diabases on Bonaire. These diabases do not differ from the
diabases described. Kloos, who examined them (lit. 23) mentions oHvine in one of them
(Ma. 196, l.c.p. 94). I had an opportunity to have a look at Martin\'s material, but I could
not find olivine in No. 196. Kloos speaks of: ,.vollständig serpentinisierten, durch . . .
staubförmigen Magnetit deutlich zu erkennenquot; (l.c.p. 94). Most likely Kloos took aggregates
of chalcedony, surrounded by a rim of magnetite crystals, for serpentinized olivine. In the
corresponding section one can see fresh, hardly coloured or pale green aggregates of fibrous
chalcedony, surrounded by a rim of finely divided magnetite grains. Occasionally some
fibrous chlorite is present in these aggregates of chalcedony, giving, though very faintly,
the idea of ,,Maschenstrukturquot;. Similar aggregates occur in some other diabases (e.g. Ma.
183b), but smaller .sized.

2.nbsp;Most of the diabases are non-porphyritic and most of them are amyg-
daloidal. The mineral matter of the amygdales varies greatly in composition
and in the arrangement of the components.

3.nbsp;The spareness of the primary composing minerals. As such only feld-
spar and pyroxene deserve consideration, and in the quartz (bearing) diabases,
quartz; other minerals are failing or, when present, they are of minor importance.
Sometimes magnetite can be of some importance.

4.nbsp;The predominance of feldspar, which the diabases have in common
with all the other Washikemba rocks.

5.nbsp;The absence of olivine. I wish to point out that there is nothing peculiar
about the absence of olivine, since olivine-free diabases are well known rocks,
but the character is worth mentioning.

The porphyrites are the most important rocks of the Washikemba forma-
tion, in the first place because they have the greatest variation of all the Washik-
emba rocks, in the second place because they form a great many intnisions in
the Washikemba beds, in the third place because the greater part of the Washik-
emba tuffs are derived from a diorite magma.

Because the intrusions of porphyrite correspond entirely with the lava
flows, the following descriptions are based both on intrusions and lava flows.

When fresh, the porphyrites are mostly light brown rocks, also brown, red, reddish
brown, grey or violet grey. When weathered the colour is generally dark brown or reddish
brown, occasionally grey. The porphyrites invariably show scattered phenocrysts of feldspar
in a dense matrix. The phenocrysts are, with very few exceptions, medium grained; pheno-
crysts smaller than 1 mm. are exceptional; in some porphyrites phenocrysts of more than

5 mm. are present, up to 8,5 mm. The matrix is fine, mostly very fine grained, the greatest
dimensions not exceeding 0,3 mm. This matrix is holocrystalline and its mineralogical
constituents are predominantly feldspars, next to which magnetite and apatite can be present
and a varying amount of secondary minerals, represented by chlorite, sericite, quartz,
epidote, limonite, ? haematite and chalcedony. Not unusual is the presence of some dust
in the matrix. The predominance of feldspar in the porphyrites is very striking, even much
more so than in the diabases. The phenocrysts always consist of feldspar, the other minerals
being restricted without exception to the matrix.

We will first treat the feldspar of the matrix, then the remaining components of the
matrix and after that the phenocrysts.

Matrix. Feldspar. The feldspar is merely plagioclase, orthoclase is not present
in any porph5Tite. The plagioclase shows, just as in the diabases, a large variety in consti-
tution, owing to an advanced state of albitization of the greater part of the feldspar, for
the characteristics of which I refer entirely to the diabases. The feldspars show a divergence
from labrador to albite; commonest are albite and albite-oligoclase. The plagioclase is gene-
rally lath shaped or xenomorphic; prismoid plagioclase crystals are less common. Twinning
occurs only in the bigger crystals. Mostly the plagioclase has a dusty appearence, and here
and there the crystals have been partially modified into chlorite or sericite, less common
is a modification into epidote, whether or not accompanied by limonite.

Magnetite. Probably this mineral occurred in all the porphyrites and it is still to be
found in the greater part of them; in a few porphyrites, however, it seems to have been
entirely modified into limonite or haematite, since these ores were found only in the rocks
concerned. It chiefly occurs as numerous small grains, in places in bigger crystals. Modifi-
cation of a part of the magnetite into limonite or haematite is very common, though only
in a few cases all the magnetite has been modified (see above).

Chlorite. The chlorite, which is generally accompanied by limonite, the commonest secon-
dary mineral, is the same that we know from the diabases. It usually has a green colour,
but it is often yellow or yellowish brown, as a result of the accompanying limonite.

Epidote was found in a small number of porphyrites, accompanying the other secondary
minerals. Both pistacite and zoisite occur.

Phen ocrysts. The constitution is the same as that of the plagioclase in the matrix.
The form is chiefly prismoid and twinning is usual. A certain amount of secondary minerals
in the phenocrysts is common. These secondaries are chiefly sericite and chlorite, in places
accompanied by epidote, limonite or quartz. By way of exception the entire crystal can be
chloritized. Enclosures in the phenocrysts are apatite and magnetite, apatite being commo-
nest.

It is possible that some aggregates of chlorite and limonite have been derived from
ferro-magnesium minerals. Most probably these ferro-magnesium minerals are mica, for
we shall see later on, under the mica bearing porphyrites that the mica can change in a
large measure into chlorite and limonite (see p. 17). Since we are not able to become better
informed about the nature of the chlorite and limonite aggregates, it is not possible to make
sure that under the described quot;porphyritesquot; mica bearing porphyrites do not occur. Should
these aggregates turn out to be decomposition minerals of mica or other ferro-magnesium
minerals, then it may also be likely that there really existed phenocrysts of those ferro-
magnesium minerals, for some porphyrites contain aggregates of the said secondaries of
the size of feldspar phenocrysts, moreover provided here and there with a certain crystal shape.

Among these rocks we can distinguish porphyrites without quartz
phenocrysts, consequently only provided with a quartz bea-
ring matrix, and those provided with quartz phenocrysts.

The former are ordinary Washikemba rocks, because they occur throughout the Washi-
kemba formation, and are in fact the comnaonest kind of porphyrites, if not of all Washi-

kemba eruptive rocks. The latter (quartz bearing porphyrites and quartz porphyrites with
quartz phenocrysts) are represented by a few rocks, some of which are only known as pebbles
while the pétrographie nature of the others is dubious. About those dubious rocks I will
speak further on (see p. 17 and 22). Differences between the two kinds of quartz bearing
and quartz porphyrites as regards constitution and structure will follow from the following
descriptions.

In the field these rocks are not distinguishable from the porphyrites, since their habit
is the same as that of the porphyrites and the quartz crystals, being limited to the matrix,
are not big enough to be discovered without the aid of the microscope. The sizes of pheno-
crysts and matrix minerals are somewhat less divergent than those of the porphyrites:
phenocrysts smaller than 1 mm. are not exceptions (phenocrysts of little more than 0,5 mm
were found); on the other hand the phenocrysts do not exceed 5 mm; the matrix constituents
amount to more than 0,5 mm (in the porphyrites up to 0,3 mm.). In one quartz porphyrite
there could not even be made a distinction between phenocrysts and matrix, this rock thus
showing a pilotaxitic texture (B. 526, D. 12359; Fontein).

The quartz of these porphyrites appears in the same way as described under the quartz
bearing diabases and quartz diabases, viz. generally as xenomorphic crystals in the interstices
of the rods of feldspar. The motives, why the quartz is considered primary, are the same as
mentioned there. Moreover, by way of exception, the quartz can be hypidiomorphic.

In general the plagioclase is the same as that of the porphyrites. Remarkable is the
appearance of small spherolites of plagioclase in some of the porphyrites in question, forming
as it were, miniature variolites. The largest diameter of these spherolites is 0,5 mm., the
average size is only a little smaller. These spherolites are often accompanied by rods, needles
and small granules of ore (haematite and (or) limonite). These ore particles can encircle the
spherolites of feldspar, or can occur among the fibres of the spherolites and in the latter
case, they are consequently arranged radially. In places the spherolites are imperfect, so
that part of them (generally the centre) shows small idiomorphic feldspar crystals In one
section (D. 12368, of rock No. B. 535; S. of Seroe Oom Wie) there was observed feldspar
and quartz with granophyric intergrowth, partially developed as more or less complete
spherolites.

Spherolites of feldspar have only been met with in the quartz bearing porphyrites and
quartz porphyrites. I do not know whether their presence in these rocks is an essential
character or merely accidental.

Nearly one fourth of the quartz bearing porphyrites and quartz porphyrites contain
a small quantity of orthoclase. I have not separated the orthoclase bearing porphyrites
from the orthoclase free ones, because the former do not differ from the latter in any
other essential point than the presence of potash feldspar. The orthoclase was found in the
matrix as well as in the phenocrysts.

In a few quartz bearing porphyrites uralite occurs, for the greater part chloritized.
As to the minerals magnetite, apatite, chlorite and epidote, I can refer to what has been
said about the porphyrites; the same applies to the aggregates of chlorite and limonite.

Some unquestionable rocks of this group occur among the pebbles of the Rincon for-
mation and of the Soebi Blanco conglomerate. In the Rincon formation one pebble of this
kind was found (B. 29, D. 11907), in the Soebi Blanco conglomerate two (B. 21, D. 11899
and B. 24, D. 11902). Further a quartz porphyrite with quartz phenocrysts is present in
Delft in the collection of Duyfjes, labelled: „vallei van Rincon, Bonairequot;. Probably this
rock was gathered as a pebble, which is also the impression I got, when seeing the sample.
It is possible that the rock sampled by Duyfjes, is also a pebble of the Rincon formation.

We do not know if these quartz porphyrites with quartz phenocrysts belong to the Washi-
kemba formation. Solid rock exposures of unquestionable quartz porphyrites with quartz
phenocrysts have not been met with on Bonaire. The exposures that have been found, are
of rocks of doubtful nature (see also p. 22). These have been found on the W. slope of the
Seroe Brandaris (collection Grutterink), E. and W. of the Seroe Dos Poos (W. Bonaire)
and between the Guatemala and Lamoenchi Plantations (E. Bonaire).

Because it is likely that the pebbles under consideration of the Rincon formation and
the Soebi Blanco conglomerate belong to the Washikemba formation, I will describe them
here with the restriction: unquestionable exposures of quartz porphyrites with quartz
phenocrysts are not known on Bonaire. Below I shall return to the subject of the dubious
rocks.

The porphyrites with quartz phenocrysts contain in a very fine grained matrix pheno-
crysts of feldspar and quartz. The matrix is built up of xenomorphic feldspar and quartz;
the quartz may be partly secondary. Here and there lath shaped feldspar occurs. The feldspar
of matrix and phenocrysts is chiefly acid plagioclase, occasionally rather basic plagioclase.
Other components of the matrix are granules of magnetite and chlorite, the latter being
secondary. The size of the phenocrysts amounts to 2,5 mm. The feldspar phenocrysts can
contain some sericite. The quartz phenocrysts frequently show some resorption.

In connection with the preceding I shall say a few words about the dubious rocks. These
rocks are unstratified and provided with big feldspar crystals, partially also with quartz,
in a very fine grained matrix of xenomorphic mineral matter. This mineral matter is feldspar
or feldspar and quartz, accompanied by some small grains of magnetite and secondary
minerals (chlorite and limonite). Silicification of the matrix has frequently taken place.
Sometimes some idiomorphic lath shaped feldspar occurs in the matrix; in those cases there
is a great probability that the concerning rock is a porphyrite. Some of the rocks in question
show accumulations of feldspar crystals, a phenomenon, pointing out as well that most
likely we have to do with porphyrites. But in many of these rocks it is very difficult or im-
possible to decide: porphyrite or tuff. It is most difficult to come to a decision in the case of
the quartz porphyrites with quartz penocrysts, because the mineral matter of the matrix
of those rocks is mostly xenomorphic. When, moreover, the matrix is largely silicified or
chloritized, it is obvious that it becomes almost impossible to decide, what the nature is
of the rock in question. I may add that almost without exception the dubious rocks in the
field gave the impression of tuffs or tuffbreccias. This fact does not plead so strongly for the
tuffaceous origin of the dubious rock as it seems to do, for it has occurred once or twice that
a rock, called a tuffbreccia in the field, turned out to be a porphyrite under the microscope

Be that as it may, we are guaranted in considering the occurrence of quartz porphyrites
with quartz phenocrysts among the Washikemba rocks to be most likely.

mica bearing porphyrite (B. 530, D. 12363) and mica bearing quartz
porphyrite (B 531, D. 12364).

These two rocks will be considered together, since their only difference is the absence
or presence of primary quartz, and since they are the only two rocks in which mica was
found with certainty.

B. 530 was found on the Seroe Wamari (E. Bonaire), B. 531 on the Seroe Dos Poos
(W. Bonaire).

Besides the presence of mica, the rocks are ordinary Washikemba porphyrites. The
mica is brown biotite. In the porphyrite (B. 530, D. 12363) it occurs as phenocrysts and in the
matrix, in the quartz porphyrite (B. 531, D. 12364) it is restricted to the matrix. The biotite
of the matrix is developed as small scales, that of the phenocrysts forms fine idiomorphic
crystals, grown simultaneously with the feldspar phenocrysts. The phenocrysts of biotite
are smaller than the greater part of the feldspar phenocrysts. Many of the biotite scales
of the matrix also show idiomorphism to some extent. Chlorite and limonite occur with
the biotite as a result of the alteration of the mineral. In extreme cases the entire crystal

has changed into an aggregate of chlorite and limonite. As similar aggregates occur in
a great many other porphyrites, it is most likely that mica bearing porphyrites are much
more frequent than one would be inclined to judge from the mica, that has been actually
found (see p. 15).

Exposures of pyroxene porph3nrite of Bonaire are not known. But in the waste of the
Rooi Toena (NE. Bonaire) a pebble of this rock has been found.

It is a holocrystalline rock, containing in a fine grained matrix phenocrysts of pyroxene
and feldspar. The matrix is built up of feldspar, pyroxene andquot; magnetite; the feldspar
chiefly is very fine grained and xenomorphic, for the rest lath shaped; the pyroxene consists
of small grains and small prisms; the magnetite of highly limonitized granules. The feldspar,
both of matrix and phenocrysts, is albite and oligoclase, the pyroxene of matrix and pheno-
crysts is the well known diopsidic pyroxene, here being colourless or pale green. The pyroxene
phenocrysts exceed those of feldspar in number and size (up to 7 mm.). Some pyroxene
crystals are twinned. The pyroxene can have changed into chlorite and limonite. Magnetite
also occurs as an enclosure in the pyroxene. A few amygdales that are present in the rock,
contain chlorite and calcite.

Amygdaloidal porphyrites are rarer than amygdaloidal diabases. Among the minerals
in the amygdales only silica is common. In many porphyrites geodes and amygdales with
agate occur, often accompanied with quartz. Fine agates were found on the Seroe Bezoe,
the Seroe Hobau, the Seroe Largoe (all the three W. Bonaire) and on the Seroe Grandi
(E. Bonaire). The rim of many amygdales consists of agate, which passes into quartz towards
the core. Other minerals occurring in the vesicles are chlorite, calcite, magnetite and epidote.
In all cases the principal constituent is quartz, the other ones being mere accessories. The
magnetite often forms a rim of fine granules in the amygdales; generally it is limonitized
in some degree.

One porphyrite deserves to be specially described (B. 354, D. 12449; findspot: SE. of
Washikemba Plantation. The mineral matter of the amygdales of this porphyrite is prin-

cipally chlorite, calcite and quartz. The quartz forms the rim of the amygdales, in the centre
of which chlorite or calcite is found. Some of the calcite amygdales are surrounded by a rim
of chlorite, which in its turn is surrounded by a quartz rim, other calcite amygdales are
surrounded by a rim of fine grained ore, this being surrounded again by quartz. Other
amygdales contain within a quartz rim — chlorite or ore rim, a core of calcite and feldspar.
Judging from refraction index this feldspar is a potash natron feldspar, possibly a potash
bearing albite (fig. 2, 3).

The feldspar is partly xenomorphic, being of the same date as the calcite, partly it
shows idiomorphic lath shaped and prismoid crystals, which are often twinned. In the
second case the feldspar is consequently of earlier date than the calcite, in one vesicle the
idiomorphic feldspar crystals occur in the chlorite rim, thus being of earlier date than the
chlorite. Some vesicles are filled with epidote, partly accompanied with feldspar. The occur-
rence of feldspar in amygdales was already mentioned under the amygdaloidal diabases
(p. 13). Because the diabase in which this feldspar was found, belongs to the intrusive
diabases, the occurrence of this feldspar will be described under those rocks (p. 25). As
far as I know, secondary feldspar in amygdales was never found before. Without doubt
the find is very interesting, but there is nothing strange or incomprehensible about it.

Just as in the amygdaloidal diabases we see that the arrangement of the different
minerals that fill the amygdales, greatly varies.

Quartz, chalcedony, chlorite, epidote and limonite also occur in veinlets in several
porphyrites; here too the quartz is by far the most important constituent.

Washikemba rocks with a considerable amount of potash feldspar are very rare. There
is only one rock that can be called without doubt a porphyry (B. 524, D. 12357); beside
this one more rock might bear the name of porphyry (B. 511, D. 12344). But for the occur-
rence of a great quantity of orthoclase these two rocks agree with the porphyrites. Both
rocks also contain plagioclase (albite and oligoclase). In D. 12357 some primary quartz
was found. In both rocks the orthoclase is present in the matrix and among the phenocrysts.
It is important to know that the two rocks very much resemble each other. It is possible
that they are connected intrusions (see p. 26), though the distance between their exposures
is considerable, B. 524 being exposed on the Kibra Guarati (E. Bonaire), B. 511 on the
Hobau (W. Bonaire).

A few words may yet be said about possible vitrophyric parts in the matrix of some
porphyrites. On p. 15 it was stated that the matrix is always holocrystalline. However, I do
not wish to reject the possibility, that glass though only in traces, occurs or occurred in
certain porphyrites. As such we may consider small, generally brown coloured masses with
dusty appearance and very feeble birefringence.

Kloos describes from the collection of Martin quot;mica porphyritesquot; and an quot;orthoclase
porphyryquot;.

His mica porphyrites correspond with the porphyrites I described that contain numerous
accumulations of chlorite and limonite, for which porphyrites I pointed out the possibility
that they have been mica bearing porphyrites. In none of the mica porphyrites, described
by Kloos, the occurrence of mica is convincing. Should all the chlorite and limonite of
these quot;mica porphjTitesquot; been originated from mica, the rocks would be mica bearing
porphyrites, the quot;micaquot; never occurring in such quantities that the rocks would deserve the
name of quot;mica porphyritesquot;.

2.nbsp;Quartz bearing porphyrites and quartz porphyrites are most numerous,
the porphyrites coming next.

3.nbsp;The scantiness in kinds of primary constituents. Important are feld-
spar, quartz and ? mica.

The Washikemba tuffs are equal to the eruptive rocks, especially the porphyrites, in
monotony, so far as their mineralogical constitution is concerned. In habit, colour, grain,
stratification and structure, however, they show a considerable variation.

A first distinction has been made between tuffs provided with rock enclosures and those
containing only crystal enclosures. This seems to be a good distinction, but the distinction
has always been based on the examination of one, exceptionally two, sections of one rock.
It is clear that a rock, described as a quot;crystal tuffquot;, can contain in other parts, very near to
the slide, rock enclosures.

As far as possible, a second distinction is made between diabase tuffs, porphyrite
tuffs, etc.

In the descriptions only unquestionable tuffs have been considered. As far as necessary,
the rocks of doubtful tuffaceous origin (dubious rocks) will be mentioned apart (p. 22).

In the main diabase crystal tuffs are dark coloured grey rocks, occasionally dark green
or dark brown, very fine grained and finely stratified. However, they can be unstratified.
When weathered, which is often the case, these rocks are brown coloured. In a very fine
grained dusty matrix they contain small enclosures of crystals, which can be feldspar,
pyroxene, quartz and magnetite. One tuff contains needles of apatite. The matrix is always
highly changed; the modifications can be chloritization, silicification, limonitization, calciti-
zation and epidotization. Zeolitic minerals were also found. In one section (B. 86, D. 12113)
there was found a brown coloured sericite-like mica. Of these modifications chloritization
and silicification are commonest. Under these circumstances it is difficult to say what has
been the original constitution of the matrix. That plagioclase was, and even is, an important
constituent, is certain. In places fine granules of magnetite occur, but these might be secon-
dary. A certain amount of glass may originally have been present in the matrix too. The
chlorite is the same as we know from the other rocks: colour greenish yellow to pale green,
birefringence feeble or wanting. When mixed with limonite the colour can be brown. The
epidote is a pale green to colourless pistacite.

The enclosures vary greatly in quantity and size. Sizes above 0,3 mm. are rare. The
most important enclosure is feldspar, it is not absent in a single tuff. The enclosures of feld-
spar are rather fresh crystals or fragments of crystals of, mostly twinned, plagioclase. This
plagioclase varies from labrador to albite, albite and oligoclase being again commonest.
Pyroxene is less common and, if present, less abundant than feldspar; it is the well known
diopsidic pyroxene, colourless or nearly so. In a few sections quartz enclosures occur, in
those cases we might be allowed to speak of quartz bearing diabase crystal tuffs. The magne-
tite forms small scattered grains. Small vesicles occurring in some tuffs are filled with
quartz or zeolitic minerals.

As these tuffs only differ from the foregoing by the presence of rock enclosures, I need
not repeat what has been said there about habit of rock, matrix, crystal enclosures and
secondary changes in the rocks. The rock enclosures are never very abundant. They consist
of fine grained diabase, while in one section (D. 12114, rock No. B. 87) an enclosure of diabase

porphyrite was found. A rock of doubtful place (B. 90. D. 12117), but probably being a
diabase tuff contains rock enclosures of diabase, diabase porphyrite, ? porphyrite and
? chert. All the rock enclosures are highly changed, principally chloritized and limonitized.

crystal tuffs, porphyrite crystal tuffs, quartz bearing porphyrite
crystal tuffs, quartz porphyrite crystal tuffs.

I decided to take the porphyrite crystal tuffs, quartz bearing porphyrite crystal tuffs
and quartz porphyrite crystal tuffs together, because they are by their very nature closely
related and their differences are based upon a single character, while, for the rest, the rocks
are of the same kind. I added the crystal tuffs, partly because of the same considerations,
partly because I am convinced that they conceal some porphyrite crystal tuffs, etc., the
enclosures, however, being too scanty to say more of the rock than that it is a quot;crystal
tuffquot;. The tuffs in question are far more abundant than the diabase crystal tuffs and diabase
tuffs. Generally they are very fine grained and thinly bedded rocks, often with fresh appea-
rance and highly differing colours: from yellowish brown to dark brown, beige, sandy-
coloured, grey, greyish brown, greenish brown, light green, when silicified often dark grey.
When bedding is well developed, the various layers can have different colouring: grey,
dark brown, beige, sand-coloured layers alternating in one rock. Weathering gives predomi-
nantly brown to greyish brown, sometimes red colours, chloritization green colours, sili-
cification dark grey colours.

Just as in the diabase crystal tuffs and diabase tuffs the very fine grained, often dusty,
matrix can be highly changed, the modifications being chloritization, silicification, limoni-
tization, calcitization and epidotization. As an exception zeolitic minerals occur. Especially
silicification is very common. Few tuffs are free from secondary quartz. It is possible that
the calcite in certain tuffs is not due to secondary calcitization, but to the fact that those
tuffs were primary calcite bearing. In one tuff thin layers of limonitized pyrite occur.
Here and there glass might have been present in the matrix. In these tuffs too, little can
be said about the original constituents of the matrix; plagioclase and in some cases ortho-
clase are important. The chlorite is the same as we know from the other rocks; the epidote
is colourless or yellow or pale green pistacite or zoisite. The epidote occurs in small, fine
grained aggregates.

The enclosures in these tuffs can be feldspar, quartz, magnetite and apatite. Beside
apatite, which is always very scarse, the enclosures vary considerably in number and size.
Since the tuffs in question are sometimes difficult to separate from some dubious rocks
and since those latter rocks can have crystal enclosures of 1,5 mm. and bigger, it is impossible
to give a maximum size. We can only say that the enclosures in the distinct, well bedded
tuffs, seldom exceed 0,3 mm. The feldspar can be acid plagioclase and orthoclase; the
most frequent of all enclosures is acid plagioclase, but, relatively, orthoclase is also common.
Feldspar, especially plagioclase, is the only kind of enclosure in many tuffs, in others
again it is only accompanied with some magnetite granules. In most cases the magnetite
is limonitized in some degree. The percentage of quartz among the enclosures is very
variable.

Certain tuffs contain small aggregates of chlorite and limonite, like those described
in the porphyrites; originally these tuffs may have contained mica. I must point out the
fact, however, that mica itself was not found in any tuff.

In the section one tuff (B. 562, D. 12396) having a dull black colour, turned
out to contain a dark brown organic substance, this being the cause of the colour of
the rock.

Some tuffs contain remains of organisms; these are principally radiolaria; in a few
tuffs they are foraminifera. The skeletons of the radiolaria. and the cavities they enclose,
can have undergone the same changes as the rocks in which they occur. Thus chloritized,
calcitized and entirely silicified radiolaria were found. Martin has also found some radiolaria
in his samples of Bonaire tuffs.

As these rocks differ only from the respective crystal tuffs by the presence of rock
enclosures, it is sufficient to treat the latter ones here. The rocks in question are not so
numerous as the respective crystal tuffs. Occurring rock enclosures are porphyrite. chert,
diabase, ? diabase porphyrite.

When treating the porphyrite crystal tuffs and similar tuffs, we said that orthoclase
is relatively common in those tuffs. Crystal tuffs, however, in which orthoclase predominates,
are very rare or fail on Bonaire. I examined two rocks, which we might call porphyry crystal
tuff: B. 547, D. 12380 and B. 549, D. 12382; one that might be a porphyry tuff: B. 550,
D. 12383 and D. 12384. Of these rocks B. 547 is a rock of doubtful tuffaceous origin. The
rock enclosures that were found in D. 12383 are chert.

The bad state of conservation of these rocks, the alteration and albitization of the feldspar
make it difficult to take a decision. Be that as it may, when porphyry crystal tuffs and
porphyry tuffs do occur on Bonaire, they certainly do not occur in abundance and then
they are porphyry (crystal) tuffs relatively poor in orthoclase. Tuffs in which plagioclase
fails or almost fails are unknown.

Under the names diabase breccias and porphyrite breccias some breccious, conglo-
meratic or agglomeratic volcanic rocks, composed of rock fragments, are united. In the
diabase breccias the rock fragments are diabase, diabase porphyrite and amygdaloidal
diabase; in the porphyrite breccias these are porphyrite. The nature of the matrix varies,
now resembling that of the non-stratified tuffs, now that of the diabases or porphyrites.
In the latter cases it can be amygdaloidal, the vesicles being filled with chlorite or quartz
or both. The matrix is always highly changed, the most important secondary mineral
being chlorite; other occurring secondaries are limonite, quartz, chalcedony and epidote.
Without exception the matrix contains several crystals and fragments of crystals. In the
diabase breccias these crystals can be feldspar (from anorthite to albite 1), magnetite and
apatite. In one and the same rock anorthite, bytownite, labrador and andesine or labrador,
andesine and oligoclase can occur together! In the porphyrite breccias acid plagioblase,
orthoclase and quartz occur. In places the feldspar can be chloritized, sericitized, silicified,
epidotized or calcitized.

It is obvious from the preceding that the breccias are apt to be mixed up with tuffs
provided with rock enclosures.

The principal things about these rocks have already been said in connection with the
quartz porphyrites with quartz phenocrysts (p. 17 ). To give a summary, we have to do
here with unstratified rocks, with a very fine grained matrix, composed of xenomorphic
mineral matter; in this matrix crystals of feldspar or feldspar and quartz of various
dimensions have been found. Generally these rocks are highly altered. The impression one
gets in the field and in the section, the crystals of varying size and the nature of the matrix
point to tuffs; the want of stratification, the large, often idiomorphic, crystals, the fact
that in places lath shaped feldspar can appear in the matrix, and finally the total want of
remains of organisms point to eruptive rocks.

In his descriptions of Bonaire tuffs Kloos indicates several times the presence of
„hyaline Substanzquot; in the matrix (lit. 23, pp. 101 ff.). The original presence or absence
of glass in the matrix of the tuffs cannot be proved anymore. When re-examining the tuffs

collected by Martin, I noticed that they are highly silicified and chloritized. Consequently
nothing certain can now be said about their original nature. At present the tuffs are entirely
crystalline. One of them (No. 194) contains a brown, dusty substance that may have been
glass, but at present it is crystalhne too. As things are, it is possible and even probable that
glass occurred in the matrix of a part of the tuffs, but it is not to be proved.

The cherts, radiolarites and jaspers are hard, dark coloured rocks, stratified or unstra-
tified, often with splintery cracks. Generally the original colour is black or bluish black,
weathering causes grey, sometimes brown or brownish grey colours. The red varieties
— jaspers — contain ore, which can be magnetite, pyrite, haematite, and (or) limonite.
Impregnation with chlorite causes dark green colouring.

The silica in the cherts is very fine grained, granular or spherolitic. In some degree
calcitization has taken place in many cherts. Often chlorite and ore are present, the latter
being principally limonite and haematite, sometimes magnetite or pyrite. Veinlets, which
are often present in the cherts, can be filled with quartz or calcite.

In some of the cherts there occur small crystal enclosures, being feldspar and quartz.
I do not doubt that a part of the cherts are silicified crystal tuffs. But whether all the cherts
must be considered as such, which was supposed by G. J. H. Molengraaff regarding the
Curasao cherts, is doubtful (lit. 32, pp. 20,21 ). Tuffs can be highly silicified, but they
could nearly always be distinguished from the cherts, Transitions from tuffs to cherts are
not known on Bonaire.

Many cherts contain radiolaria. Of the radiolaria in the radiolaria bearing cherts and
in the radiolarites only the cavities have generally been preserved, filled with silica or
calcite.

Molengraaff says that the cherts cannot have been deepsea deposits, his argument
being the occurrence of foraminifera in some cherts. As long as the foraminifera in the
Cura9ao cherts have not been proved to be shallow water foraminifera, however, this
argument is not decisive. We do not really know foraminifera from the extreme
deepsea deposits, where radiolarian ooze is found. But we do know foraminifera from
considerable depths.

It is a different case with the discovery of tuffites, real conglomerates and foreign
material in the Knip (lit 47). This foreign material must have been brought to Curafao
by land or by the bottom of a very shallow sea. So here at least we have the evidence that
the cherts alternate with shallow water deposits.

So far as Bonaire is concerned, the cherts of that island and their relation with the other
Washikemba rocks do not give any evidences about their origin.

These rocks consist of fragments of jasper, sticked together by silica. The ore that was
found in the jasper brcccias, is magnetite and haematite. The jasper breccias can contain
radiolaria. Jasper breccias were found here and there accompanying the cherts, chiefly
in the lower parts of the Washikemba formation and chiefly in W. Bonaire (W. of Goto
and E. of Dochila).

The Washikemba limestones are dense, fine grained rocks, generally dark coloured:
grey, greenish grey, dark grey, black, brown, Pure limestones are grey to black, the other
colours being due to accessories. These accessories can be chlorite, pyrite, limonite. In places
the calcite can be recrystallized. No trace of organisms was ever found in the limestones.

Clear intrusions of diabase are not numerous; except one. perhaps two, exceptions
they are limited to a region in W. Bonaire approximately situated between Rincon and the
Seroe Soempina. The principal one is that which forms the Seroe Caracao (B. 53) which
possibly is a sill. SE. of the Seroe Caracao occur a few more sills, among which the Seroe
Piedra Pretoe; the other intrusions of diabase in this region must be considered as necks
Several exposures of the same diabase intrusions lie E. and SE. of the Seroe Caracao They
have been marked on the geological map. Outside this region an exposure was found in
Terra Hoendoe (E. Bonaire — B. 540). Possibly another intrusion of the same diabase
occurs W. of Goto (B 74, D 12101). Finally rock No. 3259 (section No. 2318) of the collection
of Grutterink is a similar diabase, but of this we do not know the solid rock. It was found
on the NW. slope of the Seroe Grandi. It may be a pebble out of the Soebi Blanco conglo-
merate. The intrusive diabases under consideration are easily distinguishable from the
ordinary Washikemba diabases. In the field already one sees that one has to do with another
kind of rock: the intrusive diabases are fresh, dense, hard, dark coloured rocks the colour
being dark grey to dark greyish green. Hence the name quot;Piedra Pretoequot; (black rock). With
the naked eye feldspar, ferro magnesium minerals and ore are to be distinguished As a
result of their hardness the diabase necks and sills form in the landscape small, generally
isolated, bare hills, more or less dome shaped.

In the museum of the St. Thomas college in Cura9ao there are preserved several axes
originating from Bonaire, and formerly made by the Indians. The material which some of
these axes have been made of, is diabase. Without doubt these axes were made of the hard
diabase of the necks.

Under the microscope the intrusive diabases turn out to be medium to coarse grained
rocks (crystals of more than 6 mm. occur) with gabbroid or doleritic structure. Chief com-
ponents are feldspar, pyroxene and magnetite, other components are apatite, uralite, chlorite,
sericite, limonite and zeolitic minerals.

Feldspar. The feldspar varies from bytownite to albite, of which oligoclase and andesine
are most numerous. The feldspar is oblong shaped to prismoid. Generally the feldspar is
strongly modified; dusty and with sericite, chlorite and zeolitic minerals- among the
secondary minerals the latter are commonest. Probably only sericite and chlorite are to be
considered as minerals originated as a result of the decomposition of the feldspar, the zeolitic
minerals being a secondary impregnation in the feldspar. For these zeolitic minerals occur
in great quantity outside of the feldspar crystals, in amassments and veinlets. One can often
observe that these veinlets continue into the big feldspar crystals. Two zeolitic minerals
can be distinguished, the one being a natrolite-like pale brown to creamy mineral, finely
and indistinctly fibrous, with a very low refraction index and birefringence, sometimes
with feeble pleochroism; the other one in appearance agreeing with the first one, but with
a high refraction index.

Pyroxene. The pyroxene is the same that is present in the other diabases, a monoclinic,
diopsidic pyroxene, colourless, pale green to pale yellow or pale violet, sometimes with
feeble pleochroism (from pale green to yellow); generally with distinct and strong cleavages
irregularly cracked or with well developed sub-quadratic cleavage. Enclosures are sparse
apatite needles and magnetite granules. The pyroxene can to some extent be decomposed
to chlorite or secondary mica, sometimes accompanied with quartz.

Idiomorphism is less developed and less common than with the feldspar, that is to say
a part of the pyroxene may possess well developed idiomorphism, the remaining pyroxene
being hypidiomorphic and (or) xenomorphic. Nevertheless one gets the impression that
feldspar and pyroxene are of the same date or for the greater part of the same date, part
of the pyroxene then being of later date than the feldspar. Here and there feldspar and
pyroxene crystals have gro^vn together, occasionally the pyroxene gives the impression
of being an enclosure in the feld.spar crystals.

In places small accumulations of pyroxene crystals are to be observed, indicating an
early crystallization of the pyroxene.

Magnetite. It is a common constituent of these diabases, occurring in small grains and
some bigger crystals.

Uralite. This mineral is seen in many spots, showing a dirty green colour. It is generally
associated with chlorite into which it passes.

Chlorite. In occurrence and habit the chlorite does not differ from the kind found in
the other diabases.

For the sake of completeness I may add that the diabase in the collection of grutte-
rink (No. 3259), which is a quartz diabase, has a sub-gabbroid structure, and contains several
big uralite aggregates, partly with a core of pyroxene. It is all but certain that the uralite
in this diabase and also in the other ones resulted from the pyroxene. The quartz in quartz
diabase no. 3259 occurs in the same way as in the other quartz diabases; partly the quartz
crystals are bigger.

Also in the collection of Boldingh a gabbroid diabase was found. However, the find-
spot of this diabase is not given. This rock consists of a coarse grained fabric of bytownite
and diopsidic pyroxene with magnetite and numerous chlorite aggregates and with the
zeolitic mineral with low refraction index that we know from the other intrusive diabases.

The rock B. 74 (D. 12101). which may also be an intrusive diabase is a medium
grained rock with doleritic structure, essentially consisting of acid plagioclase. diopsidic
pyroxene and magnetite, with accessory apatite and secondary minerals: chlorite, sericite,
epidote, quartz, limonite. Part of the quartz may be primary. It shows some likeness with
the gabbroid diabase of the boldingh collection. In the field this rock was recognized as
an intrusion.

Though the intrusive diabases differ in several respects from the ordinary Washikemba
diabases and the two kinds of diabases clearly represent distinct types, they doubtless
belong together, only being different manifestations of the same geological event.

The close connection of the intrusive diabases with the ordinary Washikemba diabases
is made the more admissible, since a few intermediate types have been found. These are
diabases, by their geological relation belonging to the normal Washikemba diabases, by
their mineralogical structure and texture, however, reminding one of the gabbroid intrusive
diabases. As such may be considered B. 62 (NE. of the Seroe Grandi, E. Bonaire; D. 12089)
and B. 73 (250 m. N. of Salina Tam, W. of Goto, W. Bonaire; D. 12100); possibly B. 74 (see
above) too. These diabases are principally characterized by the considerable amount of
diopsidic pyroxene they contain, this pyroxene being predominantly xenomorphic.

On the other hand there has been found an exposure of an amygdaloidal diabase
which matches quite well with the corresponding Washikemba rocks (B. 60, D. 12087)
The rock is exposed approximately 400 m. NW. of the Seroe Grandi, W. Bonaire. In the -
field this exposure shows itself as an intrusion: amidst a flat country, principally showing
diabase waste with here and there exposures of weathered and easily weathering Washikemba
rocks, lies a small outcrop of hard, dark coloured, unweathered diabasic rock. Under
the microscope this rock turned out to be an amygdaloidal diabase (B. 60). This rock
contains, among others, amygdales of feldspar (already mentioned on p 13 and p. 19).
The feldspar occurs in amygdales up to 1,5 mm. diameter; the rim consists of fibrous chlorite,
m the centre is found the feldspar, relatively coarse grained or fibrous. In some vesicles
chlorite and feldspar lie pell-mell, showing no arrangement whatever. According to its
refraction index the feldspar is an acid plagioclase (fig. 4).

The above proves the great uniformity of all the diabasic rocks; the same holds good
for the porphyrites.

When consulting the accompanying geological map one sees, several long, narrow
stripes running roughly parallel to the summits of the quot;Seroesquot; and marked as quot;Intrusions

of porphyrite.quot; Many of these stripes correspond in broad outline with the general strike
of the Washikemba formation. Others, on the contrary, make an acute angle with this
general strike. Finally there are many areas, indicated in the same way, which show no
definite direction.

The stripes that run parallel to the general strike of the Washikemba formation, gene-
rally show very limited dimensions in the direction of that strike. They are porphyrites that
are normally intercalated among the rocks of the Washikemba formation. Their impersistence
in the direction of the general strike of that formation make it most unlikely that we have
to do with lava flows here. In my opinion all of them must be considered as sills. The stripes
of porphyrite that make an acute angle with the general strike are undoubtedly discordant
intrusions. On the geological map we can see that in some cases these latter intrusions are
connected vrith the sills. (Seroe Hobau: Seroe Palmit; Seroe Dos Poos; SE. prolongation of
the Seroe Matado di Pascoe — NE. of the Seroe Kimeterio). In these cases we see the part
that runs parallel to the general strike, in close and unseparated connection with the dike,
making approximately an acute angle (in the case of the Seroe Hobau more than 90 degrees).
There can be no doubt that the NW.—SE. directed part of the porphyrites under conside-
ration are sills. In connection with the N. dip of the Washikemba rocks it is impossible that
the approximately NE.—SW. running part of these intrusions represents the volcanic
pipe that fed the N.W.—SE. running part. The only explanation for these intrusions is that
they are sills, from which discordant intrusion in the overlying strata has taken place.
Another fine example of a discordant intrusion connected with a sill can be seen N. of the
Washikemba Plantation (ca. 1250 m. WNW. of Boca Washikemba).

The intrusions that have no definite direction (apparently), must partly be considered
as necks, partly as discordant intrusions. Examples of the latter are the Seroe Bezoe and
the Seroe di Camina (W. Bonaire).

Stripes of porphyrite like the Seroe Brandaris, Seroe Largoe (W. Bonaire), SE. prolon-
gation of the Seroe Largoe, Seroe Joewa, Seroe Makoetoekau and E. of the Seroe Kimeterio
(all of them in W. Bonaire) may be also sills. In these cases, however, we have no proof that
they are so. In my opinion they are sills and on the geological map I marked them with the
signature of the intrusions. The same may be said of the large stripe of porphyrite N. and E.
of the Seroe Corra and including this hill.

Remarkable are the numerous small outcrops of porphyrite SE. of the Seroe Pietji
Lang. These may be necks, but I am inclined to think that they once formed, together with
the Seroe Pietji Lang itself and with the porphyrite outcrop NW. of the Seroe Pietji Lang,
an extensive coherent intrusive mass of porphyrite, which has been largely dissected by
subsequent erosion. The same may be said of the Seroe Bezoe and its northwestern prolon-
gation.

As has been mentioned already (p. 14), the intrusive porphyrites resemble the ordinary
Washikemba porphyrites in every respect. The rock examination in the laboratory cannot
tell us anything about the geological nature of the rock; we must entirely rely on the field
data.

It is not my intention to give here a detailed summary of the occurrence of
late-cretaceous volcanic rocks in the West-Indies, their points of resemblance
with and divergence from the Washikemba formation. Giving such a summary
would be totally unnecessary because the occurrence of late-cretaceous volcanic
rocks on several Antillean islands and their relationship have been given several
times by authors. Such rocks have become known from Curasao, Aruba, Cuba,
Haiti, San Domingo, Jamaica, Porto Rico, the Virgin Islands, St. Croix, St.
Barts, St. Martin, ? Anguilla, ? St. Kitts. Possibly the igneous basement of the

isle of Antigua (up to now considered as being of eocene age) is also the result
of cretaceous volcanic activity. Cretaceous sediments from Antigua have been
described recently by Cushman (lit. 7). The connection between this Cretaceous
(foraminifera bearing chalk) and the igneous basement is not known. At any
rate it is important that Cretaceous has become known on Antigua. There is a
great similarity of rocks from the igneous basement of Antigua with some Washi-
kemba rocks, as is illustrated by a description of rocks of the igneous basement
of Antigua, given by K. W. Earle (lit. 10).

The co-occurrence of diabases, porphyrites, tuffs, clastic volcanic rocks and
cherts with intercalations of limestones on Bonaire is very characteristic of late-
cretaceous volcanic formations in the West-Indies. Blue beach rocks, so common
and wide-spread on Antillean islands, occur also on Bonaire. They are my por-
phyrite and diabase breccias. Intercalations of limestones are a common pheno-
menon. Cherts have become known from Porto Rico, San Domingo, chert breccias
from St. Barts, jasper from Porto Rico. For several islands it is proved that the
volcanic series under consideration is of late-cretaceous age. Cherts only occur
in the Cretaceous throughout the West-Indies. In Venezuela too the cherts are
Cretaceous (Cogollo—La Luna series). The resemblance of these cherts with
those of the Knip beds on Curasao and of the Washikemba formation is striking.

If we did not have a paleontological prove for the cretaceous age of the
Washikemba formation, the similarity of the Washikemba rocks with rocks of
cretaceous formations in adjacent regions would be a very strong argument for
the cretaceous age of the Washikemba formation.

We shall occupy ourselves a little longer with the relation of the Knip beds
on Curasao with the Washikemba formation, because it is, as a consequence
of the situation of Curagao with regards to Bonaire, of more importance.

Without doubt there are many common features in the oldest formations
of both islands. Diabases, diabase porphyrites, diabase tuffs, cherts, radiolarites,
quartz porphyrite crystal tuffs, porphyrite crystal tuffs, porphyrite tuffs, crystal
tuffs, jasper (lit. 32), limestones (lit. 47), calcareous crystal tuffs (lit. 36) occur
on both islands in the respective formations. The diabase of Curasao is older
than the Knip beds. Diabase tuffs are the oldest rocks of the Knip beds. Likewise
the diabase and diabase tuffs of the Washikemba formation predominate in the\'
lower parts of the formation. The constitution of the Cura9ao diabases agrees
quite well with that of the Bonaire diabases. Quartz diabases seem to be rare
on both islands.

However, there are several differences between the formations in question
of the two islands. 1 set the highest value on the following differences:

2.nbsp;the occurrence of tuffites in the Knip beds, which fail in the Washikemba
formation;

3.nbsp;the occurrence of foreign material in the Knip beds (see Ver:\\iunt and
Rutten) ; on Bonaire foreign material does not appear before the Rincon formation;

Especially 2 and 3 are of importance. They point out that during the sedi-
mentation of the Knip beds and the Washikemba formation the geological facial

circumstances were very different for Curaçao and Bonaire. The connection with
the continent that was accomplished for Bonaire during Rincon time must have
been brought about on Curaçao much earher.

The facts that lavas are absent in the Knip beds and that tuffites, apparently
with rounded detritical enclosures of the same material that has built up the
tuffs, do occur, is very remarkable. The tuffites point to nearness of land, land
that was overflowed by torrents of lavas. These torrents, however, could not
reach the region where the Knip beds were deposited. On Bonaire the conditions
were quite the inverse. Here tuffites are failing, but still we find lava flows
between the tuffs.

4.nbsp;the place taken by the diabase on Curaçao and on Bonaire: on Curaçao
the diabase does not form part of the Knip beds, on Bonaire the diabase is an
integral part of the Washikemba formation, it is found as far as the highest parts
of the formation. However, 1 stated already that diabase is most abundant in the
lower parts of the Washikemba formation, in this respect showing some resemblance
with the situation as it is on Curaçao. Moreover, diabase tuffs occur in the lower
Knip beds.

5.nbsp;the thicknesses of the Knip beds and the Washikemba formation are
very different. While the Knip beds get at their utmost a thickness of some
hundred meters (see Vermunt and Rutten), the Washikemba formation is several
thousands of meters thick, consequently deposited under distinct géosynclinal
conditions.

6.nbsp;the tuffs of the two islands only show a rough and general resemblance.
In the field there is often a good likeness and the tuffs agree as far as they have
been derived on both islands from a gabbroid, resp. dioritic magma. However, the
diabase tuffs of Curaçao contain green hornblende, which was not found in the
diabase tuffs of Bonaire. The hornblende in the latter ones might have been
chloritized, but then it must have been present in the diabases too and it is not
probable that it should not have been preserved in a single tuff or diabase.
Moreover, why should it have been chloritized on Bonaire and not on Curaçao.

I had the opportunity to occupy myself before with the porphyrite tuffs
from Curaçao, when giving some remarks on the geology of Ronde Klip (E. Cura-
çao) (lit. 36). I then found that:

a.nbsp;the minerals in the Curaçao tuffs are more diversified, being plagioclase.
quartz, hornblende, pyroxene, mica;

b.nbsp;quartz is generally more abundant in the Curaçao tuffs than it is in the
Bonaire ones;

d.nbsp;the quantity of remains of organisms is generally greater in the Curaçao
tuffs.

From the descriptions of tuffs given by G. J. H. Molengraaff one can
read that a. is valid for whole Curaçao.

To the W. of the Seroe Grita Kabai an intrusion of a porphyritic quartz
hornblende diorite is exposed (B. 696, D. 12442, B. 112, D. 12448). It is a weathered
grey to greenish grey rock; with the naked eye quartz, feldspar and a ferro
magnesium mineral are recognizable. The rock is fine to medium grained; most
crystals do not exceed 1 mm., in places larger crystals occur, up to 5 mm. In
rock sample No. B. 696 one gets the impression that scarce phenocrysts of ferro
magnesium minerals are present. In the corresponding section (D. 12442), however,
no phenocrysts can be observed: the rock appears to consist of a hypidiomorphic
tissue of feldspar, hornblende and quartz, with some granules of magnetite, some
needles of apatite and with secondary minerals. The feldspar is the most common
constituent, next to the feldspar hornblende is commonest. The feldspar is albite,
albite oligoclase and a small quantity of ? orthoclase. The feldspar is usually
prismoid, partially twinned, dusty and in places chloritized or sericitized. Enclo-
sures in the feldspar are needles of apatite; The hornblende is pleochroitic: almost
colourless to green; full of cracks and in places chloritized. Enclosures in the
hornblende are apatite and magnetite. The quartz is predominantly xenomorphic
with enclosures of apatite and of liquid matter.

The feldspar is clearly of the same date as the hornblende; the quartz is
partly of later date than the feldspar and the hornblende, partly of the same
date: granophyric intergrowths of quartz and feldspar are rather common.
The other section (D. 12448, of rock number B. 112) is almost alike the first one,
the only difference being the appearance of scarce phenocrysts of acid plagioclase,
up to 2,5 mm is length.

The discovery of this veinrock on Bonaire is very interesting. It has nothing
to do with the other intrusive porphyrites, in fact it is a rock different from any
Washikemba rock. In order to find comparable rocks we must go to Aruba and
Curasao. Westermann pointed out that the diorite dikes of Aruba belong to the
batholith of quartz diorite and that the diorite porphyrites of Curasao may be
derived from the same batholith, as well as the diorite dike of Bonaire, (lit. 52).

This very coherence is the interesting point of the find of the quartzhorn-
blende diorite of Bonaire.

It connects Bonaire petrographically with Aruba. For details 1 can entirely
refer to the paper of J. H. Westermann (lit. 52).

The formation consists of limestones, conglomeratic limestones and conglo-
merates, most of which are exposed W. and SW. of the village of Rincon. Beside
the area W. and SW. of Rincon outcrops of the formation occur in the village
itself and in some areas more to the SW. (SE. of the Seroe Dochila). Moreover some
limestone outcrops near the Mangasina di Rey (ENE. of Rincon) can be reckoned
to the formation. The limestones contain a great many, generally ill-preserved
fossils; gastropoda, lamellibranchiata, two specimens of a nautiloid, corals,
foraminifera and lithothamnia.

An indeterminable solitary coral which is most likely a new species belonging
to the family of the Turbinolidae but which is not sufficiently preserved to describe
under a new name will be discussed on p. 77.

The foraminifera mostly belong to the Miliolidae, beside which Textularia,
Glohigerina, Globotruncana, O-percuUna, Orbitoides and Rotalidae-like forms were
found. As the foraminifera could only be examined in slides it is impossible to
give accurate determinations.

In many slides sections of foraminifera occur which give strongly the im-
pression of Nummulites species. I am of the opinion that we have to do here
with nummulitiform Operculinas. Finds of Nummulites sp. have been mentioned
by Bela Hubbard and (with a ?) by E. T. Hodge from the Cretaceous of Porto
Rico. It is of some interest to draw the attention to the fact that also in these
cases the fossils may be nummulitiform Operculinas, so that the occurrence
of Nummulites in the Cretaceous of the West-Indies is not yet certain at all.

The occurrence of a Nerinea sp. points to Cretaceous, those of Diploctenium
and Palaeopsammia to Upper Cretaceous.

The genus Hercoglossa in America points to Upper Cretaceous or Eocene.
The fact that the Bonaire species is closest to two eocene forms {H. ulrichi and

H. peruviana) see p. 80) should indicate Eocene. However, the species is too
deplorably preserved to set much value to the determination. In connection
with the above mentioned and with the following, we can say that the occurrence
of Hercoglossa sp. fortifies an uppermost cretaceous age of the Rincon formation.

The Rincon formation lies unconformably upon the Washikemba formation.
The strata of the Rincon formation exhibit rather inconsequent strikes, but
mainly running parallel to the strikes of the Washikemba formation, with low
dips to the NE. and E. i). In places higher dips were found (40°—60°). The uncon-
formity of the Rincon formation and Washikemba formation results from the
occurrence of pebbles of Washikemba rocks in the conglomeratic Rincon rocks
and from the gentle dipping of the Rincon strata. At one place on the old road
from Rincon to Dos Poos, ca. 700 m.W. of Rincon we were able to see the plain
of unconformity (it was hidden under soil and plantgrowth, but could easily be
made visible by taking away about 2 dm. of the covering soil). As the Rincon
formation is younger than the upper cretaceous Washikemba formation I consider
the Rincon formation to be Uppermost Cretaceous. The formation reaches a
thickness of about 200 m.

The limestones are for the greater part hard, dense rocks, mainly brown,
greyish brown or greenish brown coloured, occasionally with green or greyish
green colour.

Some limestones contain numerous rock and crystal enclosures, generally
together with a great many chlorite aggregates. The rock enclosures are Washik-
emba rocks: cherts, diabases, diabase porphyrites, porphyrites, tuffs. The crystals
and crystal fragments are chiefly plagioclase (albite to labrador; most occurring
is andesine) and quartz. Besides ore (magnetite) also occurs. A part of the chlorite
aggregates is due to chloritization of enclosed eruptive rock fragments. In a
former paper (lit. 38) I considered the crystals as being of tuffaceous origin.
However, both rounded off and angular crystals occur. Moreover no predomina-
ting tuffaceous rocks are known of the Rincon formation. At present I am of
the opinion that the crystals are not of tuffaceous origin, but that they are all
derived from eroded Washikemba rocks.

The amount of crystals and of small rock fragments in the Rincon rocks
can become so great that we can almost speak of calcareous sandstones or cal-
careous micro-conglomerates.

Other limestones contain very few or no enclosures. Those latter limestones
generally contain a great number of foraminifera, so that we can even distinguish
Glohigerina bearing limestones and Miliolidae bearing limestones. Limestones with
Miliolidae in abundance were found e.g. at the Mangasina di Rey. On the whole
the limestones of the Mangasina di Rey are poor in crystal and rock enclosures.
Also the coral bearing limestones generally contain only small enclosures.

The pebbles of the conglomeratic limestones and conglomerates consist for
the greater part of Washikemba material: cherts, diabases, porphyrites, diabase

1) In a former paper (lit. 38, p. 705) I spoke of a predominating N. dip; this is not
correct and must be NE. and E. dip.

porphyrites, tuffs (partly silicified), chloritized and limonitized eruptive rock
fragments. Besides pebbles of rocks which are foreign to the isle of Bonaire were
found. These are granodiorites and granodiorite aplites.

Granodiorites. Medium to coarse grained, lightly coloured rocks, with rather fresh
habit and the structure of a granite. In most of the granodiorites quartz is abundant. In
nearly all cases a great quantity of albite is present, together with orthoclase and with
oligoclase and often with a granophyric intergrowth of quartz and feldspar. The feldspar
may be more or less idiomorphic and is often strongly sericitized, in places chloritized and
epidotized. Biotite is occasionally present. Other ferro-magnesium minerals are either
failing or altered into chlorite and epidote. Magnetite in small quantities never fails. Acces-
sories are apatite, titanite and zircon.

Granodiorite aplites. These rock differ from the granodiorites by a less pronounced
crystallization sequence. Partially the granodiorite aplites are finer grained than the grano-
diorites. I must observe, however, that there are transitions between the two kinds of rocks
and that it is difficult in certain cases to say whether the rock is a granodiorite or a grano-
diorite aplite. In those cases we can speak of aplitic granodiorites.

The origin of the foreign pebbles will be discussed on p. 37 together with
the foreign pebbles of the Soebi Blanco conglomerate. To the W. of the village
of Rincon Martin has found a conglomerate with porphyry (? porphyrite)
enclosures and a calcareous cement. This rock may belong to the Rincon formation.

The only formation with which we can compare the Rincon formation is
the Seroe Teintje limestone on Cura9ao.

Prof. Gerth ascribes a lower-senonian age to the Seroe Teintje limestone
but he could not give an exact age on the strength of the data that were accessible
to him (lit. 13). Mac Gillavry considers it to be Campanian or Maestrichtian
(lit. 25). I favour the view of Mac Gillavry who had more and new material
at his disposal. It is not of great importance that till now there have not been
found rudistids in the Rincon formation. A more important difference between
the two formations is that in the Seroe Teintje limestone does not occur foreign
material. This, however, has nothing astonishing.

In general the pebbles in the various quot;rooienquot; of Bonaire turned out to
consist of ordinary Washikemba rocks, in places mixed together with quaternary
limestones. The pebbles of the quot;rooienquot;, lying N. and S. of the Seroe Largoe or
Montagne (E. Bonaire) form a curious exception, however. A part of the material
in the mentioned quot;rooienquot; consists of Washikemba rocks and quaternary limestones,
but the greater part of these pebbles are entirely different from any Bonaire
rocks. The foreign pebbles were also found on the W. slope of the Seroe Grandi
(E. Bonaire), but here they are not so numerous.

The foreign pebbles are generally more rounded and partly they have greater
dimensions than the pebbles of the Bonaire rocks. Dimensions of 10 cm. are not
rare; the biggest surpass 12,5 cm. We do not know the primary origin of the
foreign rocks. Some suggestions about their origin will be given in the following.
But still we know a secondary deposit of the foreign rocks on Bonaire. To the
N. and S. of the easternmost part of the Seroe Largoe limestone (quaternary
limestone), we find several outcrops of a conglomerate, which has a calcareous
cement and the pebbles of which consist for the greater part of foreign rocks:
the Soebi Blanco conglomerate. The outcrops of the conglomerate are distributed
over three regions, which together do not exceed an area of about half a square
km. We may be sure, however, that the extension of the Soebi Blanco conglo-
merate is, or was, very much greater, because we find the same pebbles, as was .
said before, in all the quot;rooienquot; N. and S. of the Seroe Largoe (E. Bonaire), from \'
Gabilan to the E. and from Terra hoendoe to the NE. as far as eastward of the
Coeroe Boeroe Plantation. Again SE. of Coeroe Boeroe they were found on
the slope of the Seroe Grandi (E. Bonaire). Moreover the same pebbles have
been found in the basal conglomerate of the quaternary Seroe Largoe limestone,
and on the slope of the Seroe Grandi there were found pebbles of a quaternary
conglomeratic limestone (probably part of the basal conglomerate), containing
small foreign pebbles. Quaternary limestone does not occur in situ on the Seroe
Grandi. In the basal conglomerate of the Seroe Largoe limestone the foreign
pebbles are exposed, with interruptions, over a distance of more than 6 km
according with a surface of at least 4 square km. It is impossible that all of those
pebbles should originate from the little areas N. and S. of the easternmost part
of the Seroe Largoe (fig. 5).

The remarkableness of the pebbles is that the Washikemba and Rincon
rocks have little share in them: most of them are granodiorites and granodiorite
aplites, gneisses, quartzites and some other rocks, which for the rest do not
occur on Bonaire.

Foreign pebbles have also been mentioned from the Rincon formation,
but their occurrence in the Rincon formation differs in some regards from that
in the Soebi Blanco conglomerate:

1.nbsp;the percentage of foreign pebbles in the Soebi Blanco conglomerate
is much greater than in the Rincon formation,

2.nbsp;the foreign pebbles in the Soebi Blanco conglomerate are, generally
speaking, much bigger than those in the Rincon formation,

3.nbsp;more kinds of rocks are known from the Soebi Blanco conglomerate;
this will become clear from the list of foreign rocks that will be given in the
following.

The strike of the Soebi Blanco conglomerate obviously differs from the
strikes of the older formations, being EW.; the strata generally show a low dip
to the N. In places nearly vertical strata have been found. Fine exposures of
low N. dipping strata can be seen N. of the easternmost part of the Seroe Largoe;
vertical strata are in places exposed S. of the Seroe Largoe.

The deviation of the horizontal plane of the Soebi Blanco strata must be
considered rather as a result of faulting with drag dip than as a real folding.
The conglomerate may attain a thickness of about 400 m, an exact value cannot
be given.

The greater part of the rocks of the following list has been given
already in my quot;The occurrence of foreign pebbles on the isle of Bonairequot; (lit.
34). The list has been enlarged with rocks of the Grutterink collection.

1.nbsp;GranodioHtes. These rocks do not differ from those described from the Rincon
formation (see p. 32).

2.nbsp;Granodionte apiite. Medium grained, shghtly pressed rock, chiefly consisting of
plagioclase and quartz. Feldspars: acid plagioclase, microdine microperthite and ortho-
clase. The quartz has undulose extinction. Some biotite, muscovite and magnetite occur.
Secondary minerals are epidote and chlorite.

3.nbsp;Plagiaplite. Distinct aphtic rock, for the greater part consisting of albite and
ohgoclase, with a few orthoclase and quartz and some ore (ilmenite). In places the feldspar
has been changed into sericite or epidote. Some chlorite points probably to modified ferro-
magnesium minerals. The constitution of the feldspar places this rock among the plagiaplites
m the vicinity of the diorite-aplites; its scarcity of ferro-magnesium minerals, of quartz
and of ore give it more resemblance with the albitites.

4.nbsp;Albiteaplites. Medium to coarse grained rocks, principally consisting of quartz
and acid plagioclase, with frequent granophyric intergrowth. The plagioclase is chiefly
idiomorphic and hypidiomorphic, the quartz chiefly xenomorphic. Some magnetite is pre-
sent. Secondary minerals: epidote, chlorite, calcite (aggregates in places with crystal shape:
hornblende?).

5.nbsp;quot;Breccious apiitesquot;. Under this name I have taken together some rocks in which
quartz and feldspar (plagioclase) predominate or in which quartz predominates and which
rocks show a distinct gneissose or breccious structure. The granulation of these rocks is
highly varying, even in the same rock: feldspar and quartz partly occurring in small crystals
and fragments of crystals, partly in large crystals.

In all these rocks the quartz possesses strong undulose extinction and is cataclastic;
the plagioclase often has bent and broken twins. Some of these rocks give the impression
of a gra)nvacke-quartzite, but the angular hypidiomorphic feldspar crystals and the way
of intergrowth of feldspar and quartz can leave no doubt that the rocks in question are
gneissose or brecciated eruptive rocks. The feldspar can be strongly sericitized. Other
occurring minerals are biotite (large pressed crystals), magnetite, chlorite, epidote.

6.nbsp;Gneisses. Medium to fine grained rocks with more or less pronounced gneissose
appearance and texture. The feldspars can be orthoclase, microdine, micropertlnte, microdine
microperthite, acid plagioclase (mostly being albite and oligoclase; in some gneisses also
andesine is abundant). In some gneisses myrmekite was found. The feldspars, especially
the plagioclase, are frequently altered, usually into sericite and zoisite. Other occurring
nnnerals are quartz, biotite, muscovite, sericite, pyroxene, amphibole, magnetite, ilmenite,
pyrite, haematite, titanite, apatite, zircon. With the exception of biotite and sericite. these
components are present in nearly all cases in small quantities and even biotite and sericite
rarely occur in greater quantities. Generally the biotite is completely chloritized, occasio-
nally epidotized. The greater part of the gneisses has been e.xposed to great pressure; the
quartz possesses strong undulose extinction and is cataclastic; the plagioclase has bent and
broken twins; the biotite has been pressed between the other minerals; occasionally the
whole rock is cataclastic.

Microdine gneiss. Striking in these gneisses is the small quantity or failing of ferro-
magnesium minerals.

Plagioclase gneiss. Some of these gneisses are strongly cataclastic. They are rich in
sericite. One of them shows fine „Schachbrettstrukturquot; in the feld,spars.

Microdine plagioclase gneiss. Parallel structure fails in these gneisses. Without doubt
they are orthogneisses.

Breccious diorite gneiss. This rock resembles the breccious aplites, but it has a pronounced
gneissose structure.

7.nbsp;Zoisite quartz feldspar schist. The chief components of this rock are quartz, feldspar,
mica\'s and zoisite. The feldspar is principally acid plagioclase; the mica\'s are muscovite
and chloritized biotite. This rock was also exposed to high pressure, in such degree that
it has almost obtained a mortar texture.

8.nbsp;Quartzites. Generally rather fresh, fine grained rocks. Some quartzites are medium
to coarse grained. Beside quartz the quartzites can contain some acid plagioclase, biotite,
sericite, ore, chlorite, calcite, bituminous matter.

9.nbsp;Graywacke quartzite. Quartz largely predominates in this rock, next to which a
considerable quantity of acid plagioclase, microperthite and sericite has been found. Further-
more ore, zircon, apatite and some chert inclusions occur.

10. Quartz epidote rock. Strongly altered rock, consisting of epidote and quartz. The
quartz forms, as it were, a fine grained ma rix between the epidote, the latter occurring in
more or less globular aggregates.

11.nbsp;Polygeneous conglomerate. In a graywacke-like matrix, chiefly containing quartz,
with acid plagioclase and mica, there occur small pebbles of quartz, quartzite, chert and
plagioclase gneiss. As it is almost certain that the chert is derived from the Washikemba
formation,\'perhaps the quartz too, foreign pebbles and Washikemba material must have
been consolidated to a conglomeratic rock and very shortly after this portions of this con-
glomerate must have been taken up in the Soebi Blanco conglomerate.

12.nbsp;Silicified mica bearing shale. Fine grained, stratified, brown rock with small
crystals of quartz, plagioclase and mica (muscovite and biotite). In my quot;The occurrence of
foreign pebbles on the isle of Bonairequot; I allowed for the possibility that this rock should
belong to the Washikemba formation. By this time I am able to say that this is certainly
not the case. The rock may be compared with similar rocks from the Midden Curagao strata
on Cura9ao, although silicification of rocks of the Midden Curasao strata is not known.

13.nbsp;Amphibolite, with vein of quartz diorite and vein of epidote. Similar rocks have
been found on Aruba; in fact the rock under consideration is quite identical with certain
amphibolites described by Westermann. I shall return to this amphibolite when discussing
the origin of the foreign pebbles.

14.nbsp;Uralite diabase porphyrite. A very fine grained holocrystalline diabase porphyrite.
The rock has been subject to strong uralitization, in places some pyroxene has been preserved.
Diabases with a small quantity of uralite have been found as an exception in the Washikemba
formation, but rocks comparable with the uralite diabase porphyrite in question are not
known. It is possible that this rock belongs to the Washikemba formation; to my opinion
it is foreign.

In places finer grained sediments occur in the Soebi Blanco conglomerate,
being conglomeratic calcareous sandstones, with mineral and rock enclosures:
quartz, feldspar (acid plagioclase), magnetite, mica, chert, diabase, quartzite.

Beside the rocks, to which T referred, rocks of the Washikemba and Rincon
formations occur among the pebbles of the Soebi Blanco conglomerate. The
Washikemba rocks are represented by diabases, porphyrites, quartzporphyrites,
tuffs, cherts, jaspers and radiolarites; with respect to a pyroxene porphyrite
that has also been found, we have no evidence that it belongs to the Washikemba
formation, because pyroxene porphyrites have not been found as solid rock.
The Rincon rocks are represented by conglomeratic limestones and a litho-
thamnium bearing limestone.

The Rincon formation and the Soebi Blanco conglomerate correspond in
being both conglomeratic and both containing foreign material. The diffe-

rences are: the Rincon formation is only partially conglomeratic, the pebbles
are smaller than those of the Soebi Blanco conglomerate and chiefly consist
of Washikemba material; the Soebi Blanco conglomerate is almost entirely con-
glomeratic, there is more diversity among the foreign pebbles and the percentage
of the Washikemba material among the pebbles is decidedly smaller than that
of foreign material.

What has been said about tuffaceous material in the Rincon formation
also applies to the Soebi Blanco conglomerate: here too I must repeal my view
that tuffaceous material is present.

The age of the Soebi Blanco conglomerate cannot be fixed with certainty.
No trace of fossils has been found in it. The conglomerate is younger than the
Rincon formation, which is uppermost Cretaceous. It is older than the upper
eocene limestones, by which it is covered unconformably. This follows from the
situations as seen NW. of Terra hoendoe and E. of Gabilan. NW. of Terra hoendoe
there are approximately horizontal upper eocene limestones. In the hillside waste
E. of these limestones foreign pebbles occur. The outcrops of the Soebi Blanco
conglomerate E. of the limestones show low N.dipping strata, common to the
conglomerate. E. of Gabilan we see foreign pebbles in abundance on the hillsides
and in the quot;rooienquot; N. and E. of the limestones. These limestones are partially
Upper Eocene.

As to the origin of the foreign pebbles nothing is known, we can only pre-
sume, but nothing can be said with certainty.

The degree of rounding of the pebbles may be due to long transport, in that
case pointing to remote origin, but likewise it may be the result of wave action
before definite cementing in the conglomerate.

So far as the metamorphic rocks are concerned we know metamorphic
rocks in adjacent regions from the Greater Antilles and from the Caribbean
Coastrange in Venuzuela. Inquot; connection with the situation of the Greater Antilles
and Venezuela with regard to Bonaire, it is more likely that the metamorphic
rocks among the Soebi Blanco pebbles originated from the Venezuelan Coastrange.
Prof. Rutten described some rocks from the Caribbean Coastrange, collected
during our journey (lit. 39); he also took the origin of the Soebi Blanco pebbles
under consideration. He came to the conclusion that the gneissic rocks, oc-
curring as pebbles on Bonaire may have been derived from the Venezuelan
coastrange and more especially from the hinterland of Puerto Cabello. As to the
origin of the quartzites we cannot get any evidence.

The granodiorites and aplites of the Soebi Blanco conglomerate agree well
with some rocks from Aruba. The same can be said of the amphibolite. From
a description of rocks from the Venezuelan islands between Bonaire and Trinidad
by Prof. Rutten (lit. 40) we can draw the conclusion that comparable rocks
occur on Los Roques (aplitic granites, l.c.p. 1103) and Blanquilla (biotite grano-
diorite, I.e. p. 1104). Biotite granodiorite is also known from Venezuela (I.e. p.
1109). The intrusions of granodiorite and of aplite on Aruba are probably more or
less synchronical with the intrusions on Cura9ao, which partly are younger than the
Midden-Curacao strata. Dr. Trechmann examined some fossils from the Midden-

Curasao strata, collected by us in E.Curasao. On the strength of some of these
fossils he thought it most likely to be of eocene age. If this determination is
exact, then there is some probability too that the intrusions on Aruba are
younger than the Rincon formation and than the Soebi Blanco conglomerate.
The same can be said of the amphibolite, because the metamorphism of the
Aruba metamorphic rocks most likely took place at the same time.

It is to regret that no more is known about the rocks occurring in NW.
Venezuela (between Puerto Cabello and the Gulf of Venezuela). All speculations
about the origin of the foreign pebbles must remain hypothetical. We can only
say that rocks, comparable with some of the foreign pebbles on Bonaire, are
known to occur in the neighbourhood of Bonaire, which was a priori to be ex-
pected, and that the pebbles with most probability have originated from Vene-
zuela or, perhaps partially, from somewhere W., S. or E. of Bonaire. In the first
case we must assume a connection between Venezuela and Bonaire, in the second
case there must have been at least a considerable landmass in the vicinity of
Bonaire, of which Bonaire, anyway the quot;Bonairequot; of Soebi Blanco and Rincon
time, made up a part.

The tectonical complications with which we have to reckon in those times
will be discussed in Chapter VIII.

I must call attention to one thing yet. In the collection of Dr. Boldingh two samples
of quot;foreign rocksquot; from Bonaire occur, a gneiss and a gneissose granite. The rocks are labeled;
„Karpat Bonairequot;. Probably they were collected on the beach at Karpat. They differ dis-
tinctly from the pebbles of the Soebi Blanco conglomerate:

1. their habit is entirely different; 2. the gneiss texture of the gneiss is more pro-
nounced than in any of the Soebi Blanco gneisses; 3. mica is more numerous and is fresher;
4. the conservation of the rocks is better than of any of the Soebi Blanco rocks; 5. they
are not rounded off.

One should be careful not to confound these or similar rocks with the Soebi Blanco
rocks: the former have no relation at all with the geology of Bonaire; probably they were
brought to the island from Venezuela on board sailing vessels as ballast and thrown ashore.
During our visit we sa,w such rocks on the beach in Slagbaai; here it were angular, unweathe-
red, big cobbles of amphibolite, in every respect different from whatever Bonaire rock.

In all probability the Upper Eocene on Bonaire had a great extension.
There are two facts pointing to that. The first is the occurrence of generally small
patches of eocene deposits at several, relatively remote places. They were found
SW. of the Seroe Montagne (W. Bonaire), at three places S. and SW. of the cirque
of Rincon (at Punta Blanco and SW. of it), in the waste on the hill side SE. of
Seroe Dochila, at several places in the N.part of the Columbia Plantation
(between Fontein and Moreke) and finally NW. of Terra hoendoe. The second
fact is the wanting of terrigenous material in the upper eocene rocks, which
makes it almost certain that the entire northern part of Bonaire was covered
at the time by the eocene sea.

The Upper Eocene is represented by limestones and a foraminifera marl.
The extensiveness of the limestones is certainly larger than has been marked on
the geological map. The reason is that the upper eocene limestones can only be dis-
tinguished from some of the quaternary limestones by the presence of charac-
teristic fossils. Now one sees in several places eocene, foraminifera bearing
limestones interchange abruptly or gradually with uninforming fossil-less or
lithothamnia bearing limestones. Thus in many cases one cannot say whether
these limestones are Quaternary or Tertiary. Only localities of doubtless tertiary
limestones have been marked on the geological map. An eye cast on the map
will make it probable for the extensiveness of those limestones to be larger.

Data about the situation of the Eocene could only be obtained in the region
SW. of the Seroe Montagne. There we found an EW. strike of the strata with
a low dip to the S. (15°—30°).

Of all the formations on Bonaire the Upper Eocene is richest in fossils.
The area SW. of the Seroe Montagne (W.Bonaire) yielded most of the echini
and so called quot;largerquot; foraminifera. We owe the discovery of this rich locality
to a small nigger boy Aloysius, who had found some fossils there and brought
them to our camp in Dos Poos. There could be distinguished two zones in this
region: a lower zone characterized by a species of large lamellibranchiata, which
could not be determined more exactly as only internal casts have been found,
and an upper zone containing echini and larger foraminifera.

In the areas S. and SW. of the cirque of Rincon echini were found, in the
N.part of the Columbia Plantation and NW. of Terra hoendoe larger fora-
minifera. Other fossils found in the upper eocene limestones are corals, mol-
lusks, a Terebratula, a decapod. Of the material that allowed determination

a list will be given below and, as far as necessary, descriptions will be given in
Chapter X: Paleontology.

The echini bearing limestones are generally beige to light brown rocks, the
foraminifera bearing limestones are light brown or they have the colours of the
quaternary limestones: white, pink, grey, yellowish, brown.

In a limestone, which he considered to be quaternary, Martin has found
fragments of foraminifera, which he thought to belong to the genus Orhitoides.
He supposed the foraminifera fragments to be of cretaceous age and to have
drifted into the quaternary limestone. We may be sure that Martin has found
an eocene limestone.

List of fossils found in the upper eocene limestones.
Foraminifera.
Lepidocyclina {Lepidocyclina) v. douvillei Lisson 1921

hieronymi (M. Rutten amp; Vermunt 1932)
schotborghi M. Rutten amp; Vermunt 1932
irinitaiis H. Douv. 1917
[Helicolepidina) spiralis Tobler 1922
Lepidocyclina sp. sp.

Discocyclina {Asterocyclina) aurarensis Hodson 1926
,,nbsp;,,nbsp;bontourana Hodson 1926

Operculina curasavica M. Rutten amp; Vermunt 1932
,, nummulitiformis L. Rutten 1928
bonairensis n. sp.
sp.

Nummulites vanderstoki M. Rutten amp; Vermunt 1932 (In lit. 62, p. 239 this species was

Echinoidea.
Cidaris melitensis Forbes 1855
Bonaireasier rutteni n. gen. n. sp.
Amblypygus cf. merrilli Twitchell 1915
Pauropygus ovum serpentis (Guppy 1866)
Antillaster sp.

Schizaster sp., cf. subcylindricus Cotteau 1875
,, gerthi n. sp.
Lamellibranchiata.
Pholadomya trechmanni n. sp.

The occurrence oi L.r. douvillei, L. trinitatis, H. spiralis, Discocyclina, 0. num-
niulitiformis, Nummulites, Serpula clymenioides point to Eocene; Agassizia con-
radi is in the West Indies only known from the Eocene; Amblypygus merrilli is
an upper eocene species; the occurrence of L. hieronymi, L. schotborghi, the sub-
genus Asterocyclina, 0. curasavica point to Upper Eocene. Pauropygus ovum
serpentis is known from the Eocene and from the Oligocene; CidansmelitensishQ.s
become known hitherto from the Oligocene and from the Miocene. Schizaster
subcylindricus is an eocene species. A strocoenia portoricensis \\idiS only been found
hitherto in the Oligocene (see p. 77). As the Bonaire species was found in a region
with exclusively eocene rocks, I also consider it to be of eocene age. Comparing
the Bonaire fauna of larger foraminifera with Table I of Gorter and Van der
Vlerk (lit. 60) and retaining the old quot;marginquot; of Eocene and Oligocene, the
tertiary limestones of Bonaire get approximately a middle-upper eocene age.
If we place this margin at the Paloma alta-series as is proposed in the mentioned
paper, then the Bonaire limestones are transitional between Oligocene and
Eocene. The same can be said of the Seroe di Cueba limestone on Curafao, although
that limestone may be slightly older.

The foraminifera marl was found in a newly dug draw-well near Porta
Spano (NW. part of the Columbia Plantation), at ca. 15 m. depth. The well
was dug in quaternary limestones, which cover the marl. The locality has been
marked on the geological map with a special signature. The foraminifera
marl is a grey coloured, soft rock. It yielded a large fauna of so called quot;smallerquot;
foraminifera and some ostracoda.

Most likely the marl is slightly older than the upper eocene limestones:
at a distance of 600 m. upper eocene limestones, lying ca. 50 m. higher, were found;
at a distance of 850 m. upper eocene limestones, lying 35—40 m. higher, occur.
We can get no certainty, however, because nothing is known about the position
of the strata in this region.

Little can be said about the thickness of the upper eocene limestones.
Probably they do not attain a considerable thickness. About the thickness of
the marl nothing is known.

martini n. sp. Common.
Textulariella barreitii (Jones amp; Parker)? Common.
Vulvulina molengraaffi n. sp. Rather common.
Gaudryina bonairensis n. sp. Few.
Tritaxia cognaia {Vcrncuilina Rss.) Few.

var. portaspaamp;ocnsis n. var. Ratlier common.
thalmanni var. costata n. var. Rather common.
submimita n. sp. Rare.
hochi n. sp. Few.
,, westermanni n. sp. Few.
..nbsp;,, sp., juv. of C. thalmanni n. sp. Rare.

(Robulus) cuUrata (Montf.). Common.
curvisepta Seg. Few.
inornata d\'Orb. Common.
mexicana Cushman, juv. Rare.
{Saracenaria) acutauricularis Fichtel amp; Moll. Few.
vermunti n. sp. Few.
macgillavryi n. sp. Rare.
sp.

Ischloenbachi Rss., anomalous specimen.
Frondicularia tenuissima Hantken. Rare.
Glandulina discreta Rss. Common.
,, globulus Rss. Few.

laevigata d\'Orb. Rather common.
,, strobilus Rss. Rather common.
Nodosaria acuminata Hantken. Few.

,, globifera Rss. Few to rather common.
radicula (L.). Rather common.
subnitida Nuttall. Few.
,, vertebralis (Batsch). Few.
vutteni n. sp. Rare.

{Dentalina) consobrina d\'Orb. Rather common.
soluta Rss. Common.
,, verneuili d\'Orb. Rather common.

sulcata (Walker amp; Jacob). {Nodosaria scalaris d\'Orb.?). Rare.
,, sp. {Nodosaria hispida d\'Orb.). Few.
Nonion umbilicatulus (Montagu). Few.
bonairensis n. sp. Fairly rare.
hummelincki n. sp. Few.
Plectofrondicularia rutteni n. sp. Few.

Hantkenina longispina Cushman. Fairly rare.
Angulogerina molengraaffi n. sp. Rare.

macgillavryi n. sp. Few to rather common.
Bolivina advena Cushman, var. elongata n. var. Few.
plicata d\'Orb. Few.
martini n. sp. Rather common.
Bulimina affinis d\'Orb. Very common.

inflata Seguenza. Common.
Siphonodosaria abyssorum (Brady). Rather common.
Uvigerina mediterranea Hofker. Very common.
,, pygmaea d\'Orb. Common.
,, westermanni n. sp. Rare.
bonairensis n. sp. Rare.
Baggina thalmanni n. sp. Common,
Discorbis vilardeboana (d\'Orb.). Rare.
Lamarckina vermunti n. sp. Few to rather common.

cocoaensis Cushman. Common.
Siphonina ? pulchra Cushman. Common.
CassiduUna californica Cushman. Few.
laevigata d\'Orb. Rare.
,, subglobosa Brady. Rather common.
Ptdlenia bulloides (d\'Orb.). Rare.
Globigerina bulloides d\'Orb. Rather common.
cretacea d\'Orb. Common.
inflata d\'Orb. Common.
triloba Rss. Common.
,, sp. sp.
Orbulina porosa Terquem. Few.

,, universa d\'Orb. Few.
Globorotalia crassula Cushman amp; Jarvis. Rather common.

kochi n. sp. Rather common.
Anomalina subbadenensis n. sp. Few to rather common.
Bonairea coronaeformis n. gen. n. sp. Few to rather common.
Cibicides dispars d\'Orb. Very common.

kallomphalius (Guembel). Rare.
,, americanus Cushman. var. bonairensis n. var. Common.
megalocephalus n. sp. Very common.
Dyocibicides rutteni n. sp. Few to rather common.
Plantilina mexicana Cushman. Very common.
cocoaensis Cushman. Few.

The marl has been brought to the Upper Eocene on the strength of the
following fossils: Cristellaria (Robtdus) mexicana (M. and U. Eocene of Mexico),
Hantkenina longispina (Upper part L. Eocene to basal part U. Eocene), Eponides
cocoaensis (Jackson Eocene — Priabonian — Cocoa Sands of Gulf Coast),
Globorotalia lehneri (Eocene of Trinidad), Cibicides dispars (Mostly Cretaceous,
also Eocene of Dalmatia), C. megalocephalus n. sp. (U. Eocene of Mexico —
see p. 74), C. kallomphalius (Eocene of the Bavarian Alps), Plamdina cocoaensis
(Jackson Eocene — Priabonian — of the Gulf Coast).

It contains some species known from the Eocene and Oligocene:
strobilus (Germany), Nodosaria acuminata (U. Eocene and Oligocene of Hungary),
N. subnitida (Trinidad); some species only known till now from the Oligocene:
Frondicidaria temnssima (in Mexico), Eponides byramensis (L. Oligocene of the
Gulf Coast), Siphonina? pulchra (U. Oligocene), Planulina mexicana (In E. Mexico
L. Oligocene). The other species are either occurring in younger formations
{Lagena trigona, Pliocene of Java; CassiduUna californica, Pliocene of California;
Bolivina advena, Miocene of California) or occurring both fossil and recent.

According to Dr. Thalmann the marl has most probably a basal upper
eocene age; about its facies he informed me that the marl is a typical offshore
deposit with similar conditions as the Chapopote formation of E. Mexico (,,deep-
water phasequot; of the Tantoyuca formation, according to storrs cole, lit. 54,
p. 8, lit. 55, p. 204) and of the Aragon formation of E. Mexico.

Most of the quaternary limestones are coral limestones, in places they are
lithothamnia bearing limestones and mollusk (mostly bivalve) bearing limestones.
An exact age of the quaternary limestones cannot be given, nor a differentiation
in age either. Fossils characteristic for distinct zones have not been found. Of
course the horizontal limestones of S. Bonaire and of Klein Bonaire as well as
the limestones of the lowest terrace are younger than the limestones of the Seroes
Montagne (E. Bonaire: 133 m.; W. Bonaire: 143 m.) or than the tilted limestones
W. of Goto.

It is not necessary to give general remarks about the quaternary limestones,
e.g. about the terraces, about the nature of the limestones, about erosion and
,,lapiesquot; (Karren), etc. All these generalities have been fully described by Martin:
to say more about them would be a repetition of the remarks made by him.

Martin tried to classify the limestones, but he did hardly succeed. Probably
the lowest terrace agrees with that on Curagao, but it cannot be entirely due
to Daly\'s quot;subrecent worldwide sinking of ocean-levelquot;, since it is very in-
constant. It lies at a height of ca. 2—2,5 m., ranging from 0,5—3 m.; in places
it consists of two terraces. The terraces on Bonaire are real terraces of abrasion,
with fossil seacliffs, coves and fossil quot;boca\'squot;.

The higher terraces are as inconstant as the lowest terrace(s): of varying
height and in places merging. These terraces cannot either be the result of eus-
tatic movements only, they point to differential movements of the island in
quaternary time.

Martin considered the inclination of all the quaternary limestones to be
primary dips. For the relatively strong dipping limestones (e.g. the Seroe Domi
limestone on Curasao) his view is abandoned. He may be right, however, as
far as the very low dipping limestones are concerned. On Bonaire we can find
such limestones, mostly with seawards dips or with dips of some degrees in
various directions (e.g. near Deenterra). The irregular dips and flexures in the
quaternary limestones, which are most distinct in NW. Bonaire (near Goto dips
to 35° occur, near Boca Slagbaai to 20°) are in my opinion due to upwarping.

Phosphate. In contrast with Curasao and Aruba the quantity and
quality of phosphate found on Bonaire are nowhere such as to motify their
working. As far as I know Santa Barbara is the only place which called some
attention but mining never was carried through.

Small patches (quot;pocketsquot;) of phosphate have been found at several places
on the island. I can fortify Martin\'s experience that the phosphate on Bonaire
is generally strongly alternating and mixed with carbonate of lime. In slides
of limestones small concretions of phosphorite among the calcite often occur:
these are the very phosphoritic limestones, mentioned by Martin (lit. 27, p. 474).

Hughes, who paid a short visit to the Dutch West Indian islands Curaçao,
Aruba and Bonaire and had a view at the phosphate deposits of these islands,
mentions the remarkable particulars as follow about Bonaire (see lit. 20, p. 81):
quot;In the next island to Curaçao (Bonaire) I have seen the coral over an area
of two miles to contain fossil bones and teeth scattered in all directionsquot;. It
is quite incomprehensible where Hughes has seen these bones and teeth, as
we have not found anywhere phosphate deposits of any importance on the island.
I even wonder, if Hughes with the quot;next island to Curaçaoquot; has not mixed
up Bonaire with Klein Curaçao. \'
List of fossils.
Corals.
Orbicella cavernosa (L.)

annularis (Ell. amp; Sol.)
Favia ? fragiim (Esper)
Meandrina cerebrum (Ell. amp; Sol.)

quadrata Edw. amp; H.
Siderastrea siderea (Ell. amp; Sol.)
Agaricia ? fragilis (Dana)
Dichocoenia sp?

,, palmata (Lmk.)
Porites astreoides Lmk.
poriies (Pallas)
Lamellibranchiata.
Area deshayesii Hanley {A. aff. deshayesii Reeve)
Lucilla tigerina I-.
Venus cancellata Lmk.
Venus sp.

Gastropoda.
Bidla media Phil.
Strombus gigas L.
Volutolyria musica L.
Cyclostoma megachile Pot. amp; Mich.
Pupa uva L.

All of these are Quaternary species (for Stylophora see p. 77). Follows a list
of fossils found by Martin in the Quaternary of Bonaire or mentioned in his
publications.

Corals: Orbicella annularis (lit. 65, p. 27; lit. 66, pp. 364 ff.; lit. 41, p. 655); Meandrina
labyrinthiformis (lit. 65, p. 48; lit. 41, p. 65c5); M. strigosa (Dana) (lit. 65, p. 57; lit. 66. p. 420:
lit. 41, p. 655).

Lamellibranchiata: Ferna sp. (?) (lit. 26, pp. 475, 479; lit. 41, p. 661); Pecten sp (lit 27
p. 126; lit. 41, p. 661).

Gastropoda: Strombus gigas (lit. 27, p. 127; not mentioned in lit. 41); Vermetus sp
(lit. 26, pp. 475, 479; lit. 41. p. 663).

Vertebrata. Pisces: Carcharodon (aff.) megalodon Ag. (lit. 26, pp. 475 ff.; lit. 27, pp. 81,
104, 105, pi. I, fig. 3—7; lit. 41, p. 666) I do not think it impossible that this specimen has
been found in tertiary rocks; Oxyrhina (?) gomphodon Müll. amp; Henle (lit. 26, pp. 475 ff.;
lit. 27. p. 105. pi. I, fig. 8—10; lit. 41, p. 666); Myliohatis sp. (lit. 27, p. 105. pi. I, fig. ll|
lit. 41, p. 666); ?? Diodon (lit. 27, p. 105, pi. I, fig. 12; lit. 41, p. 666). Mammalik: Manatus sp.
(Ut. 27, p. 104; lit. 41, p. 667).

To the alluvial deposits detritus, waste, coral sands, coral shingle and
dunes belong. Waste is found in the rooien and in the handshaped inland bays
as far as they are dry land. Coral sands are principally found in S. Bonaire.
Sometimes among the coral sands thin beds of limestones are found, which are
composed of coral sands, stuck together in wet season. These limestone beds
contain numerous shells of land snails {Cyclostoma megachile). Coral shingle
is found along the coast, where it is not too high above sea-level, that is chiefly
in S. Bonaire, on Klein Bonaire and at the entrance of most of the bays and
quot;salina\'squot; (former bays). There are only few dunes on Bonaire; on the topographi-
cal map they are marked along the E. coast (E. of Lamoenchi and ca. 2% km.
S. of Lac), along the W. coast of S. Bonaire and on Klein Bonaire. Along the
E. coast of S. Bonaire and on Klein Bonaire, however, walls of coral shingle
are predominating.

The oldest rocks on Bonaire are of volcanic origin: the lavas, tuffs, etc.
of the Washikemba formation. The intercalations of marine sediments (limestones,
cherts, calcareous cherts) among the volcanic rocks and the occurrence of foramini-
fera in the tuffs point out that the formation is a marine deposit. The thickness
of the formation (at the least 5000 m.) proves it to be deposited under real géosyn-
clinal conditions. If we may consider cherts and radiolarites as deep sea deposits,
then there must have been oscillations of the unknown basement of the Washik-
emba formation during its sedimentation. The find of a real conglomerate with
calcareous cement and evidently a coral fauna in the highest part of the Washik-
emba formation indicates that the youngest layers of the formation certainly
were deposited in shallow water.

In upper cretaceous time and probably very soon after the deposition of
the formation, at any rate before Rincon time (Uppermost Cretaceous) the forma-
tion was folded or tilted, in the latter case with some complications. The deviations
from the general direction of the strike, though being scanty, the variation in the
dip, the occurrence of some dips to the S., and especially the analogy with Curaçao,
where we find the strongly folded Knip beds, make it more probable that real
folding took place and that the Washikemba formation on Bonaire is the N. wing
of a flat anticline. As to the intrusions it is probable that the greater part or all
of them took place before the folding: as has been stated before the intrusions are
petrographically closely connected with the volcanic rocks of the Washikemba
formation, in fact only the intrusive diabases could be distinguished (and even
not in all cases) from rocks of the Washikemba formation. All of them must be
intrusions brought about while the Washikemba formation came into e.xistence.
Of course this does not hold good for the porphyritic diorite vein rock: in all
probability this rock is synchronous with similar intrusions on Curaçao and Aruba
(Lower Eocene?).

On the folded and denuded Washikemba formation the limestones, conglo-
merates and conglomeratic limestones of the Rincon formation transgrediated.
After the denudation of the Washikemba formation there has been tilting,
because the Rincon rocks lie unconformably on the Washikemba formation and
the pebbles found in the conglomeratic rocks of the Rincon formation are for
the greater part Washikemba rocks. The Rincon formation with its corals and
conglomerates is a typical shallow water deposit. As the Rincon formation has

only N.dips and it is found, especially in its N.parts, in a flat country, it must be
faulted in the N. and NE.

In the interval between Rincon formation and Soebi Blanco conglomerate
there has been tilting again: the Rincon formation emerged from the sea, other
parts of the Washikemba formation sank below sea level, on these parts the Soebi
Blanco conglomerate was deposited. For the same reason as the Rincon formation
the Soebi Blanco conglomerate must be faulted at its N. border.

The deviation from the horizontal plane of the layers of Rincon formation
and Soebi Blanco conglomerate must rather be considered as tilting than as
real folding. In that direction points the monoclinal dip; not even secondary
folds have been found. I can only ascribe the steep dips occurring in places in the
Soebi Blanco conglomerate to faulting, taking into consideration the generally
low dips of the strata of the conglomerate.

There must have been complicated tectonical movements during the sedi-
mentation of Rincon formation and Soebi Blanco conglomerate. Of the foreign
pebbles only granodiorites and granodiorite aplites occur in the Rincon formation.
At the time of the sedimentation of the Rincon rocks the configuration of the
land S. of Bonaire has evidently been in such a way that only those rocks
could get into the Rincon formation. With the transgression of the Soebi Blanco
conglomerate the supply of foreign pebbles increased in a high degree; at the
same time the Rincon formation rose above the sea level, for we find Rincon
rocks among the Soebi Blanco pebbles.

Tertiary. The foraminifera marl points to a strong positive change in level
in post-Soebi Blanco time, followed by a negative change in level: the foramini-
fera marl is an off-shore deposit of the deeper sea; the upper eocene limestones
are shallow water deposits.

At present the tertiary deposits (Upper Eocene) are found only over a
relatively small surface of the island. In chapter VI I made it probable that the
Tertiary is more widely spread than has been marked on the map, and that it
might have covered all the older formations, because almost nowhere terrigenous
material from the older formations was found in it. Data about the strike and dip
of the Eocene were only obtained in the region SW. of the Seroe Montagne
(W. Bonaire). We find there a slight upwarping of the Eocene. We do not know
whether this upwarping is only local, but a priori this is not probable. The up-
warping is certainly prae-quaternary, as the quaternary limestones of the Seroe
Montagne lie unconformably on the Eocene limestones. It is quite comprehensible
that most of the Eocene has been taken away by erosion, because the isle of
Bonaire or what was the isle of Bonaire in that time seems to have been dry land
during the rest of the tertiary period.

Quaternary. The quaternary limestones are most certainly not all of the same
age: the low limestones of S. Bonaire are younger than e.g. the limestones of the
Seroe Montagne or than the inclined limestones W. of Goto. Exact relations in
age cannot be given. The inconstant character of the terraces of abrasion and
the local upwarpings in the quaternary limestones point to differential movements
of the island or part of the island in quaternary time.

Remarkable are the considerable sea depths in the immediate vicinity of Bo-
naire and even between Bonaire and Klein Bonaire. They give a strong suggestion
of tectonical movements in subrecent times.

During the Upper Cretaceous there have been géosynclinal conditions, ceasing
before the main orogenesis in upper cretaceous time. Till upper eocene time we
find shallow water deposits, after and perhaps during their sedimentation tilted
and faulted. At the base of the Upper Eocene there must have been a considerable
positive change in level, followed by a negative change in level. Differential
movements of the island continued till quaternary time.

As it is, the conditions are different from those on Curaçao and the N. part
of S. America. On Curaçao the main orogenesis falls after Midden-Curaçao time
that is almost certainly later than the main orogenesis on Bonaire. In the N. part
of S. America: NW. Venezuela and Columbia, the Eocene has géosynclinal deve-
lopment and the main orogenesis occurs in post-eocene time. The tectonics on
Bonaire and Curaçao have more similarity with the Laramid orogenesis in N.
America.

Our geological survey of Bonaire was made for reasons of pure scientific
nature. Consequently we did not make detailed investigations concerning the
geohydrology of the island. Nevertheless something can be said about the geohy-
drology, the watersupply and its improvement being of so much importance
on this and many other Antillean islands.

On Curasao experience has learned that the diabase is the best water-
bearing rock of the island. Porphyrite is not known of Curasao. The fact that
the rich well of Dos Poos lies in a porphyrite region demonstrates that the
porphyrite can be also water bearing (I also mention the well N. of Tres Kroes,
S. of Coeroeboeroe).

In the region E. and NE. of Kralendijk there is much diabase: a wide strip
of diabase (ca. 1 km.) runs from SE. of Terra hoendoe in ESE. direction to Rooi
Lamoenchi. In this region there lie the good wells of the Aruba Plantation and
the well W. of the Guatemala Plantation (property of the government). N. of
this region porphyrites and tuffs are chiefly found, in places also diabase.

As on Curafao the building of dams at the right places would be of much
importance. They may stop the superficially running water, so that it penetra-
tes into the ground and becomes groundwater and as such flows much slower
to the lower parts of the island. Downstream the dams wells can be dug.

3.nbsp;the rooi that runs E. of Seroe Bara di Carta to Punta Blanco (not to
confuse with Punta Blanco in the cirque of Rincon);

4.nbsp;the small rooien that run to the W. through the Aruba Plantation (to
dam up upstream of the Aruba Plantation).

The cirque of Rincon is chiefly a diabase region. Through the building of
dams in the various rooien (rather high upstream) it must be possible to hold
more water. The Put Dominica (put = well) is a good well. It lies at a height
of ca. 75 m. at the S. border of the cirque of Rincon. Probably it gets its water
under similar conditions as the spring of Fontein and the spring of Hato on
Curagao: the rain-water sinks through the limestones till it reaches the unweathered

Some of the names mentioned liere are not given on the geological map. One
should consult the topographical map 1 : 20.000.

less permeable basement, then it floats over the basement to the lowest point.
\\\\Tien we visited the well known St. Thomas College on Cura9ao, Pater Euwens
told me an interesting experiment that he took when being a priest in Rincon.
The wells in the village of Rincon are rather bad. They only carry water when
there is plenty of rainfall. In dry season the villagers have to fetch their water
in Dos Poos and in the Put Dominica. Pater Euwens had a siphon made from
Put Dominica to the foot of the hill, so that it was no longer necessary for the
villagers to climb the hill. The siphon was used some time, but later on it was
neglected and got out of use. If Put Dominica really is a rich well it would be
worth while to build a new siphon with a waterpipe to the village of Rincon.

Wells with similar conditions as Put Dominica can be dug at other places
along the boundary of the limestone; NNE. of Punta Blanco there is a good
chance to get water; between Punta Blanco and Put Dominica the waterparting
is probably too close to the N. boundary of the limestone.

In W. Bonaire (Fourth District) there is a rather strong difference in the
levels, consequently the rooien have a strong fall and one runs the risk that,
when one builds dams, the ground upstream of the dam will be very soon silted
up. Apart from this difficulty there can be obtained much more water in W.
Bonaire, because a great part of the rain-water flows down to the sea. There is
much diabase in this part between Boca Slagbaai and Goto.

1.nbsp;the rooi Camia, which can be dammed up at the foot of the Seroe Jarabi
di Mangle, but which has strong fall;

2.nbsp;the rooi coming from the Seroe Kimeterio. Downstream it can be dammed
up as far as close to Goto; it is recommendable to build also dams higher
upstream;

4.nbsp;the rooi of Poos Chikitoe (it can be dammed up very well near Poos
Chikitoe);

5.nbsp;the rooi that debouches into Salina Tam; it drains a region with much
diabase and porphyrite (Seroe Wekoewa).

Duvfjes pointed out that the building of overground dams is insufficient,
because the water floats too rapidly through the weathered top-soil (lit. 9). He
proposes to build subterranean dams, resting on the unweathered, hardly permea-
ble rock. 1 cannot judge if the suppositions of Duyfjes are founded, nor can 1
appreciate at their proper value the objections made by Molengraaff to the
proposals of Duyfjes (lit. 32). Should subterranean dams ever be built on Bonaire,
then the high and relatively flat limestone regions can furnish excellent quot;cisterns.quot;
Subterranean dams might be built with success S. of Fontein, near and NNE. of
Punta Blanco; the validity is dependent on the thickness of the limestones and
on the physical condition of the underground. However, in view of the precarious
economical condition of an island as Bonaire and the great expenses, which the
construction of subterranean dams undoubtedly brings along and finely the
uncertainty whether it will really settle the matter, I should never advise to pass
on to so strong a measure on this island.

As to the limestone regions no definite rules concerning the digging of wells
can be given. As to the higher limestone regions it must be dissuaded at any
rate to dig wells. The low limestone regions of S. Bonaire and Klein Bonaire
have ever5rwhere a calcareous subsoil till below sea-level. As there are many wells
in S. Bonaire (I only mention the well S. of Terra corra and the many wells of
Lima Plantation), the groundwater floats in all probability upon the sea-water.

I will draw the attention to one thing yet. On Bonaire, as well as on Curasao
and Aruba, many trees have been cut and are still being cut for the charring of
charcoal. Where the forest has been cut down, it is nowhere planted again, so
that large regions have been deforested in the course of time. This is a very
serious fact, because a thorough afforestation is very important for the islands
for several reasons:

1.nbsp;it is a well-known fact that the flowing down of the rain-water on an
afforested hill-side is much smaller than on a bare one, so that a much greater
quantity of water can sink into the ground;

4.nbsp;the barren soil soon becomes and remains unsuitable or at the least less
suitable for cultivation.

For the benefit of the water supply and of the agriculture it is very recommen-
dable to re-afforest the barren ground as far as possible and to cut for the pro-
duction of charcoal on a more reasonable base. Perhaps it will be best to stop
charring entirely for a couple of years. One must not forget that a quot;forestquot; on
Bonaire can be cut down in some months, but that it takes years and years to
get a good forest back again.

In my descriptions I have principally followed Cushman\'s quot;Foraminifera,
their classification and economic usequot; (lit. 57). Only in some respects I have
deviated from his views. Thus I retained the genus Cristellaria, with subgenera
Robulus, Plamdaria, etc. This was done in the consideration that the species
of the genus \'■\'Cristellariaquot; form a coherent group, and that there is no more
difference between forms like e.g. Robulus and Saracenaria, which Cushman
considers to be distinct genera and forms like e.g. Etilepidina and Nephrolepidina,
which are usually considered as subgenera. For the same reason I take Dentalina
as a subgenus of Nodosaria (the differences between Dentalina and Nodosaria
are, moreover, very inconstant). I refuse to accept the name Camerina instead
of Nummulites, even though the name Camerina has the priority. The name
Nummulites with its derivations is so generally used, it has found its way so far
and wide in the paleontology and geology that I think it justified in this special
case not to live up to the principle of priority.

The figures given, chiefly of new species, are all pen-drawings. I have made
pen-drawings instead of photographs in the first place because of financial con-
siderations, in the second place because of technical ones: in a drawing more
details can be given that would be invisible in a photo.

Some specimens of this form were found among the material and one of the slides
contains a specimen with large embryonal chambers (330 x 210 /x). Upper range of diameter
ca. 2,5 mm.

Loccilities. SW. of Seroe Montagne (W. Bonaire), SE. of Fontein (Columbia Plantation,
Bonaire).

Lepidocyclina {Lepidocyclina) canelleihi^m. amp; R. Douv., var. hieronymi ]\\I. Rutten amp;
Vermunt 1932, Proc. Kon. Akad. Wetensch. 35,2, p. 234 pi. I, fig. 3, pi. II, fig. 10.

This is the most common form among the material. The small, square median chambers
that distinguish this form from L, canellei Lem. amp; R. Douv. are so characteristic and constant

that I think it justified to separate it from the species of Lemoine and R. Douvillé. The
diameter ranges from 2,2 mm. to 3,0 mm., the embryon from 320 X 230 to 410 x 250 fi.

Localities. SW. of Seroe Montagne (W. Bonaire), SE. of Fontein (Columbia Plantation,
Bonaire).

This species is rather common among the material and in the slides. The diameter ranges
from 2,3 to 3,1 mm, the embryon from 400 x 310 to 550 X 360 /x.

Localities. SW. of Seroe Montagne (W. Bonaire), SE. of Fontein (Columbia Planta-
tion, Bonaire).

This species was only found in the slides, where it is rather common. The upper range
of its embryon is 640 X 550 fx.

Localities, SW. of Seroe Montagne (W. Bonaire), SW. of Punta Blanco (W. Bonaire).

A flat form, measuring 1,45 mm. in diameter with an embryon of 450 X 250 fj, may be
brought to L. schotborghi of M. Rutten and Vermunt. In the slides two forms, measuring
1,2 and 1,35 mm., both with an embryon of 550 X 500 /la were found that most probably also
belong to L. schotborghi.

Localities. SW. of Seroe Montagne (W. Bonaire), SE. of Fontein (Columbia Plantation,
Bonaire).

M. Rutten and Vermunt make mention (lit. 62,p. 234) of quot;a quite h2Lii[m^Lepidocyclinaquot;
in which the layer of median chambers is not an even plane but branched. I found four of
those forms in my slides, showing, just like the specimens of Rutten and Vermunt, three
branches going out from the embryon. Two of them could be seen to be isolepidine, but they
certainly do not belong to L. weeksi. I consider them to be mere monstruosities.

Localities. SW. of Punta Blanco (W. Bonaire), SE. of Fontein, N. of Moreke (Columbia
Plantation, Bonaire).

Most of the Lepidocyclinas are microspherical. These microspherical forms range from
4, 5—8 mm. in diameter. Distinct types could not be distinguished among them. I cannot
say to which species these microspherical forms belong. The common microspherical Lepido-
cyclina of Curaçao, L. curasavica is certainly not represented among them.

Several specimens of this form have been found, both megalo- and microspherical.
The megalospherical specimens agree well with the description given by Tobler. Among
the microspherical specimens I could distinguish two forms. The first shows only feeble
spirally arrangement in the centre; so it agrees with the type that Tobler considered as
B-forms of H. spiralis. Its diameter ranges up to 7,7 mm. The second shows spirally arrange-
ment from the centre to the periphery, consequently with two kinds of median chambers,
such as occurs in the megalospheric forms. The microspheric specimens of H. spiralis mentioned
by M. G. Rutten and L. W. J. Vermunt from Curaçao (lit. 62, p. 238) belong to this second
form. I found the diameter ranging up to ,7,2 mm.

There axe four possibihties: 1. the first form is the microspheric form of H. spiralis, as is
supposed by Tobler. Then the second form is the microspheric form of another new species
of Helicolepidina. 2. the second form is the microspheric form of H. spiralis. Then it was not
found by Tobler and his microspheric specimens were microspheric forms of other Lepido-
cyclina with spirally arrangement in the centre as it was found by Douville (lit. 59, p. 601)
and Cushman (lit. 56, pi. 34, fig. 4). 3. neither of the two forms represent the microspheric
form of H. spiralis. 4. both microspheric forms belong to H. spiralis.

Fragments of Discocyclina s.s. are common in the slides of upper eocene limestones and
some specimens have been found SW. of Seroe IMontagne. The specimens are not in such a
state of preservation that they could be determined. I mention the occurrence of specimens
of Discocyclina s.s. here, with their find-spot, because the genus is of so much stratigraphic
significance.

The Bonaire specimens that I have brought to A. georgiana agree well with the form
of Cushman .The small raised areas in the triangular flat parts are very prominent. Cushman
says df these areas;- quot;the sides . . . convex in the centrequot;; N. E. Gorter and I. M. van der
Vlerk .(lit. 60) draw more attention to these areas: quot;The parts between the arms are flat.
Sometimes these flat parts have a small raised spot near the periphery In the Bonaire
specimens these raised parts have been developed into narrow ridges coinciding with the
bisectrices of the diagonals of the square test. Thus one gets the impression that the form
is 8-rayed, but the section shows a normal 4-rayed form. The dimensions of the diameter
do not exceed those given by Gorter and van der Vlerk, but my specimens are thinner,
0,66—0,80 mm. Measurements of embryonal chambers ca. 140 X 100 The radial diameter
of the aequatorial chambers in the areas of the arms is at a distance of 1 mm. from the centre
55—80 fi, their tangential diameter is 15—30 /x. In the intermediate areas the radial diameter
of the aequatorial chambers is at a distance of 1 mm. from the centre 20—45 ju,, their tangen-
tial diameter 20—30 /n.

Localities. SW. of Seroe Montagne (W. Bonaire), SW. of Punta Blanco (W. Bonaire),
SE. of Fontein (Columbia Plantation, Bonaire).

The diameter of the Bonaire specimens ranges up to 3,6 mm; a lower range cannot be
given, because it is often impossible to see whether a specimen is complete or whether it is
broken off and rounded at the ends of the rays. Thickness up to 0,78 mm; ca. 20—26 % of
diameter. The raised terminals of the pillars (pustules) in the centre are ca. 75 /x in diameter.
Miss Hodson says that quot;the rays are small and carry only a few large pillarsquot;. If she mea,ns
by quot;raysquot; the highest ridge of the arms the Bonaire specimens agree in this respect, but in
some of the specimens there can be seen that there are pustules on the rest of the arms
(sideways of the ridge) and on the small intermediate areas as well. These latter pustules
are somewhat smaller than those of the central part (ca. 50/^). Miss Hodson found that the
centre formed the larger part of the test. This holds good for the smaller specimens; in the
larger specimens the increase in size is more due to a lengthening of the arms than to a
relative enlargement of the centre, so that the centre is no more the larger part of the test.

The embryonic chambers that are more isolepidine than nephrolepidine, measure, of two
small specimens (ca. 2,5 mm), together 180 /x and 160 fi respectively. The radial diameter
of the aequatorial chambers in the areas of the arms is at a distance of 1 mm. from the centre
75—80/A in one specimen, at a distance of 0,75 mm. from the centre 55 ft in another specimen;
their tangential diameter in both specimens is 20 (j.. In the intermediate areas the radial
diameter of the aequatorial chambers is 20—35 fi] their tangential diameter 25—30 /x.

Localities. SW. of Seroe Montagne (W. Bonaire), SW. of Punta Blanco. (W. Bonaire),
SE. of Fontein (Columbia Plantation, Bonaire).

Two specimens of A. aurarensis Hodson have been found, each being 5-rayed. Diameter
ca. 2 mm? The t^vo half embracing embryonal chambers measure together respectively
180 fjL and ca. 210 /n. The radial diameter of the aequatorial chambers in the areas of the arms
is at the greatest distance from the centre (ca. 1 mm) 55 fx,; their tangential diameter
20—25 /x. In the intermediate areas the radial diameter of the aequatorial chambers is
35 (—?60) fi: their tangential diameter is 25 fj,.

Localities. SW. of Seroe Montagne (W. Bonaire), SE. of Fontein (Columbia Plantation,
Bonaire).

Outwardly this species resembles A. bontourana. Diameter of test 2,6 mm.? (probably
larger). The megaspheric test carries 4 distinct rays and shows a tendency to form 4 more
rays, coinciding with the bisectrices of the first 4 rays. Thus one sees in the aequatorial
layers an uninterrupted peripheral series of rows of chambers between two arms. More to
the centre the rows of chambers coming from two arms converge to one point in the middle
of the intermediate area. The most central rows of chambers again run uninterrupted from
one arm to the other. In no intermediate area it comes to the forming of a real quot;arm.quot; The
character is not equally obvious in all the four intermediate areas. The species is megalospheric,
but the embryon is too badly preserved to give the dimensions. The radial diameter of the
aequatorial chambers in the areas of the arms is at a distance of 1 mm. from the centre 70 ^x;
their tangential diameter is 20 /t. In the intermediate areas the radial diameter of the aequa-
torial chambers is at 1 mm. from the centre 35 /x; their tangential diameter is 20 /x.

Though the species is very characteristic and entirely different from all other species
of Asterocyclina I have not given it a name because the present material is very insufficient.
Besides the possibility remains that it is a monstruosity.

Test very thin, planospirally coiled. Greatest diameter ranging up to 17,5 mm. Thickness
seldom surpasses 0,5 mm. There are ca. 2,5 whorls visible in adult specimens, rapidly increa-
sing in width. Chambers very numerous, ranging from ca. 15—32 in the last-formed whorl.

Chambers very narrow and high, height (that is radial dimension) ca. 15 times the length
(tangential dimension). Sutures very limbate and bent like in O. cookei, with which tins
species is closely related. Chambers widest in the middle, narrowing towards the centre
and towards the periphery. Like O. cookei some specimens of 0. bonairensis have the central
part and some of the earlier sutures ornamented by separate knobs.

As has been mentioned before this species is very near 0. cookei, from which it differs
by its dimension, number of chambers (being always less than in O. cookei for specimens that
agree in size with O. cookei), and form of the chambers.

For the measures of the described smaller foraminifera I refer to the explanations of
the figures.

Species of small size, conical, compressed, with rounded sides. Initial end pointed, test
regularly increasing in width towards the apertural end, where it is widest. Wall smooth,
finely arenaceous, with much cement. Sutures (except in the early portion) distinct, depressed.
Course of the sutures rather varying. Chambers first gradually, later rapidly increasing in
size; early chambers low and broad, later chambers higher. Aperture elongate, occasionally
slightly curved, at the inner margin of the last formed chamber and perpendicular to that
margin.

The species has some resemblance with T. subagglulinans Cushman from the Miocene
of Panama. T. subagglutinans differs by its truncated sides, by its wall being composed of
rather coarse arenaceous material and by the shape of its aperture, being more rounded.

The Bonaire species agrees in almost every respect with the species described by Jones
and Parker, which was brought to a new genus Textulariella by Cushman. I never
noticed, however, the labyrinthic chambers in my specimens. I did not separate the Bonaire
specimens from T. barrettii because they equal this species in every other respect.

Species of large size, with a wide, square, biserial part with sharp angles and a narrower,
flattened, uniserial part. Test arenaceous, surface rather smooth, with bluish grey to brown
colour. Chambers in biserial part low, in uniserial part higher. There are up to 4 chambers

in the uniserial part. Aperture an elongate slit. In a young, apparently microspheric, specimen
(fig. 19), only showing the biserial stage, the coiled early chambers are distinctly visible.

The species strongly resemblesquot; V. pennatula (Batsch 1791). It is clearly different,
however, by the square, angled biserial part and by the flat and high uniserial chambers.

The species has been named in honour of Dr. G. J. H. Molengraaff, who by his paper
on the geology and geohydrology of Cura9ao, has enriched our knowledge of the geology
of the West Indies so much.

Species of large size, from the pointed initial end rapidly increasing in width to largest
width of test, so that generally two third of the test has (roughly speaking) parallel sides.
Test in cross section triangular, with acute angles. Wall arenaceous, grey coloured. Sutures
curved, distinct, depressed, Chambers low, gradually increasing in size. Aperture very
indistinct, a transverse elongate opening in the midst of the apertural face.

This species has been named in honour of Mr. H. B. C. Schotborgh, Commander of
Bonaire.

Test fairly large, triangular in outline, with pointed initial end and largest width near
aperture. In apertural view roughly equilateral triangular with truncated apex; the base
being formed by the shortest side, provided with a more or less pronounced ridge, not forming
a distinct keel. Surface fairly rough, with much cement. Chambers few. gradually increasing
in size. Sutures not distinct, slightly depressed, straight. Aperture at the base of the inner
margin of youngest chamber, small, suboval or rounded. Triserial portion of test very small.

Test elongate-oval in outline, about 2 \'/„ times as long as wide, chambers rather narrow
and elongate. Peripheral margin rounded. There are 3 chambers visible from the exterior
on both sides; ends of the chambers rounded. Sutures distinct, deep.

The species has some resemblance with T. laevigata d\'Orb., from which it principally
differs in having 3 chambers visible on both sides, and in being more flattened. The material
is too badly preserved to describe it under a new name.

Species of large size, test bilaterally symmetrical, coiled except in the adult where the
last formed chambers tend to uncoiling. There are about 13—15 chambers in the last formed
coil. Umbilicus large, well defined. Periphery rounded, with a slightly raised ridge though
not forming a keel. Sutures distinct, of clear shell-substance, very much thickened towards
the periphery, slightly limbate. At the periphery, joining the sutures, there are 5 sack-
shaped projections composed of white shell-substance. Chambers low; later formed chambers
widening towards the periphery. Aperture terminal, radiate.

The species is close to Planularia magnifica Thalmann, var. elongata Thalmann, defined
by Brady\'s PI. 114, fig. 16 in lit. 63. Differences will be given in the following description
of P. thalmanni, var. portaspanoensis n. var., which is even more close to P. magnifica, var.
elongata.

Cristellaria {Planularia) thalmanni n. sp., var. portaspanoensis n. var. Fig. 30.

This variety differs from P. thalmanni in having more chambers in the last formed coil
(in the strict sense of the word one can no longer speak of a coil here) and in the greater indi-
viduality of the chambers, the last formed chambers not reaching the coil.

The variety is closest to P. magnifica Thalmann, var. elongata Thalmann, defined by
Brady in lit. 63, PI. 114, fig. 16. {Cristellaria compressa, d\'Orb.). It differs in being thicker,
in having more limbate sutures, in being provided with sack-shaped projections at the
periphery and in the failing of a distinct keel.

The only difference of this variety with P. thalmanni n. sp. is the presence of several
well marked costae. In most specimens there are 8—12 costae on both sides. Generally this
variety is smaller than P. thalmanni, but this character has of course no varietal value.

Species of small size, test bilaterally symmetrical, close coiled, in the adult tending
to uncoiling. There are 11 chambers in the last formed coil; chambers low, gradually increasing
in height. Sutures fairly distinct, gently curved. Aperture radiate.

The species is very close to Cristellaria minuta Bornemann 1854 from the Lias of Gottin-
gen (not C. minuta Hantken 1875 or C. minuta Hosius 1892). It differs in being more com-
pressed, in having less chambers in the last formed coil, while the last formed chambers are
higher and not turned backward at the periphery (there is in the sutures between the last
formed chambers a very slight tendency to curve back at the periphery).

Test much compressed, elongate-oval in outline, with rounded periphery. There are
only few (7) chambers in the last formed coil; the latest chambers have uncoiled. Sutures fairly
distinct, slightly curved, almost flush with the surface, narrow, widening towards the
periphery. There is an indistinct, raised umbilicus. Apertural face more or less flattened,
aperture at the peripheral angle of latest chamber, robuline.

The species resembles Cristellaria crepidula Ficht. amp; Moll as given by Brady in lit.
53, PI. 67, fig. 20. However, it has less chambers in the last formed coil and the chambers
in C. crepidula are more uncoiling than they are in P. kochi. Further P. kochi has an umbilicus,
though indistinct, and it is raised at the umbilicus.

Test compressed, suboval. Surface smooth with much clear shell-substance. There are
about 7 or 8 chambers in the last formed coil. Periphery with a broad keel of clear shell-
substance. Umbilicus large. Sutures distinct, thick, flush with the surface. Like the keel,
the umbilicus and sutures are composed of clear shell-substance. Chambers with complicated
form, as is to be seen in fig. 39. Aperture radiate, at peripheral angle of the last formed
chamber.

The species resembles to some degree Lenticulina guayabalensis Cole 1927 and Lejiticulina
velascoevsis White 1928. However, both species are thicker; L. guayabalensis has no keel and
its chambers are more uniform in size; L. velascoensis has a more rounded shape and its
chambers are more uniform in size.

The species has been named in honour of Dr. J. H. Westermann, the author of the
geology of Aruba and one of my fellow-travellers to the West Indies.

Species consisting of a subglobular initial chamber and 2 or 3 younger chambers. Sutures
highly thickened towards the periphery, of clear shell-substance, such as is found in the
sutures of P. thalmanni. Peripherally of the sutures there is another small patch of clear
shell-substance. It is possible that this species represents a juvenile form of P. thalmanni
n. sp.

Fragment of a species with few chambers, of which the last formed ones uncoil. The
species is much compressed, with parallel sides. Sutures flush, fairly distinct, thickened at
the periphery. The apertural face is not preserved, but in the last septum one can see that
it is radiate. Because the specimen is damaged I did not give it a new name.

The species is close to the form figured by Brady on PI. 67, fig. 20 in lit. 53, Cristellaria
crepidula F. amp; M., which is a Planularia subarcuatula (Williamson 1858) (see lit. 63). P.
subarcuatula has more chambers in the coiled portion of the test.

Lenticulina convergens Cole 1927, Bull. Am. Pal. 14, no. 53, p. 8, pi. I, fig. 4, 5

The Bonaire specimens have the chambers varying from 5 to 7. The course of the
sutures is also fairly variable: from entirely straight to markedly, though always gently,
curved.

One small specimen was found, with large subglobular initial chamber and two more
chambers. Sutures distinct, slightly depressed, curved. Surface smooth. I consider it to be
a juvenile form of R. mexicana Cushman.

Test biconvex, coiled, with 6 chambers in the last formed coil; last formed chamber
with a slight prolongation over the umbo. Surface smooth. Periphery rounded. Chambers
gradually increasing in size. Sutures thin, not very distinct, gently curved. The periphery
is bent outwards where sutures reach it, so that the periphery forms a broken line. Aperture
robuline, apertural face flattened.

The species is characterized by its prolonged last chamber and by its periphery forming
a broken line. It has some resemblance with C. acutauricularis, but it has less chambers in
the last formed coil and is distinctly different by the characterization mentioned.

The species has been named in honour of Mr. L. W. J. Vermont, one of my fellow-
travellers to the West Indies.

Test elongate, consisting of 5 chambers. Surface smooth. Species broadly rounded
throughout. The initial chamber has approximately the form of a semi-sphere. Third to fifth \'
chamber uncoiling. Youngest chamber swollen, narrowing towards the aperture, which is
broken in the single specimen, but must have been radiate. Although there is only one
specimen present and although this specimen is damaged at the aperture, I have given the
species a name, because it is quite characterized by its semi-spherical initial chamber, its
rapid uncoiling and the swollen last formed chamber, so that it is almost impossible to mix
it up with another species.

The species has been named in honour of Mr. H. J. Mac Gillavry, one of my fellow-
travellers to the West Indies.

Species consisting of a big, subglobular initial chamber and two younger chambers.
The younger chambers are rounded triangular in cross-section. Surface smooth. Aperture
radiate, slightly robuline.

The species has two large chambers with oblique sutures and some small earlier cham-
bers. Aperture radiate. In cross section it is short-elliptical. The specimen has some resem-
blance with fig. 8, pi. 67 of Brady 1884 (lit. 53), being probably an anomalous specimen of
C. schloenbachi Rss.

Test consisting of 6 ellipsoidal chambers, provided with 5 well developed, rather heavy
costae, which are continuous, bridging the space between the chambers. Initial part pointed.
Aperture large, rounded. Near the apertural end there is a slight curvation of the test.
The species is very characteristic by its few, pronounced costae and its pointed initial part.

The species has been named in honour of Mr. M. G. Rutten, one of my fellow-travellers
to the West Indies.

Nodosaria {Dentalina) verneuili d\'Orb. 1846, var. paucicostata n. var. Fig. 58, 59.

This variety differs from D. verneuili d\'Orb. in being provided with 3 longitudinal
costae. These costae are varying in size and development. There are specimens in which
only one costa is developed over the entire length of the test, the other two being fragment-
ary; in other specimens the costae are minutely raised so as to be only visible in the sutural
grooves.

The Bonaire species differs from the species described by Neugeboren in its number
of chambers, being much less than in N. conferta and in its form, being straight throughout,
while N. conferta is curved.

There are some specimens belonging to the sub-genus Dentalina with oblique sutures
and a peripheral radiate aperture, having moreover a rounded or oval opening at the opposile
side. Their number of chambers is varying from 3—5. The specimens are ill-preserved; I
only mention them because of tlxe peculiar opening at the opposite side.

Lagena sulcata Walker amp; Jacob 1798 [Nodosaria scalaris d\'Orb.?). Fig. 64, 65.

It is possible that Hofker is right in considering L. sulcata to be a single chamber of
N. scalaris (lit. 61). In tlie Bonaire specimens I noticed an opening at the side opposite the
neck (fig. 65). However, as long as we have no certainty about this question it is better to
keep the name „Lagena sulcataquot; for this form.

A Lagena species with the form of a decanter: a globular chamber and a stout neck.
Surface rough. It has an aperture at the end of the neck and a second opening at the opposite
side. It is possible that we have a similar case here as with L. sulcata and that this Lagena
species represents nothing but broken chambers of Nodosaria hispida d\'Orb.

Test bilaterally symmetrical, slightly asymmetrical, on both sides involute; on one
side with large umbilicus. Periphery broadly rounded. There are ca. 8 chambers in the last
formed coil. Chambers very slowly increasing in size, two last formed chambers tending
to uncoil or at the least attaining greater individuality than the preceding chambers. Sutures
fairly distinct, almost straight, slightly depressed. Aperture indistinct, at the base of the
apertural face.

Test slightly asymmetrical, involute on both sides. Periphery rounded. Umbilicus large,
especially on one side where it is slightly raised. There are about 12 chambers in the last
formed coil. Chambers low, slowly increasing in height; last formed chambers becoming
much longer. Sutures distinct, depressed, gently curved. Aperture not distinct, at the base
of the last chamber; apertural face more or less flattened.

This species has the general shape of test and chambers of Nonionina medio-costata
Cushman 1926 from the Miocene of California. However, N. hummelincki is not costate, it
has a larger umbilicus, less chambers in the last formed coil and the transition of the periphe-
ral margin to the apertural face is less rounded than it is in Nonionina medio-costata.

The species has been named in honour of Mr. P. Hummelinck, one of my fellow-travellers
to the West Indies.

Test much flattened, initial end bluntly pointed. From initial end rapidly increasing
to greatest width. Sutures distinct, very thick, flush. There are 4—6 rows of biserial cham-
bers. Chambers irregularly and slowly increasing in height. The later sutures of the biserial
stage and the sutures of the uniserial stage are thickened at the end. Sutures between the
later chambers are not continuous. Aperture an elongate slit.

The species has a rounded initial end; from the initial end it is rapidly increasing in
width. Sutures relatively thin. Sutures in the uniserial stage not continuous, thickened at
the free ends.

The species shows most resemblance with P. vaughani Cushman 1927 from the I.-ower

Oligocene of Mexico, but the latter species has continuous sutures in the uniserial stage
Age. Upper Eocene.

Hantkenina dmnblei Weinzierl and Applin, Journ. of Pal. 3, no. 4, 1929 p 402
pi. 43, fig. 5a, b.nbsp;. . ■ ,

The species is fairly rare in the Bonaire material and most of the specimens have the
spines broken. I have made H. dumblei a synonym, because the length of the chambers is
a rather varying characteristic (among the Bonaire material I often could not decide between
H. longispina and dumblei on that characteristic), as is shape and size of the spines; moreover
the latter characteristic cannot be of specific rank.
Age. Upper Eocene.

Locality. Well near Porta Spafio (Columbia Plantation, Bonaire).
Family Buliminidae.
Genus Angulogerina Cushman 1927.
Angulogerina molengraaffi n. sp. Fig. 80, 81.

Test elongate, from the bluntly pointed initial end rapidly attaining largest width.
Triangular in cross-section, with rounded angles. Sutures distinct, depressed. Chambers in
the early portion slowly increasing in height, in the later portion rapidly increasing in height.
Aperture terminal, a rounded neck.

Locality. Well near Porta Spaflo (Columbia Plantation, Bonaire).
Angulogerina macgillavryi n. sp. Fig. 82—86.

Test roughly, but clearly triangular in cross-section, with bluntly pointed initial end.
Angles sharp or somewhat rounded; sharp especially in the last formed chamber or chambers.
Sides flat, in the last formed chamber more or less concave. Chambers very individual, with
distinct sutures. Chambers with blunt prolongations over the earlier chambers. Wall smooth.
Aperture terminal, rounded, with a very short neck; in some specimens the neck is entirely \'
failing.

The species is nearest to Uvigerina selseyensis Heron-Allen amp; Earland 1909 which is
an Angulogerina. A. macgillavryi, however, is a much smaller form, with less chambers than
A. selseyenisis; the chambers of A. macgillavryi are more individual and the triangular shape
of its last formed chamber is more pronounced than in A. selseyensis.

The species has been named in honour of Mr. H. J. Mac Gillavry.
Age. Upper Eocene.

Locality. Well near Porta Spaflo (Columbia Plantation, Bonaire).
Genus Bolivina d\'Orb. 1839.

Bolivina advena Cushman 1925, var. elongata n. var. Fig. 87, 88.
This variety differs from B. advena in being longer and narrower, and more tapering
towards the initial end. In shape it resembles B. advena, var. striatella, but it is not striate
at all. It also resembles B. incrassata Rss, var. livionensis Cushman, but Cushman does not
give a figure of the apertural face of this variety: if the apertural face has the same shape

as B. incrassata, the Bonaire variety is certainly different, being much flatter and having
a more elongate and narrower aperture.
Age. Upper Eocene.

Test small, compressed. Initial end pointed, width gradually increasing towards apertural
end. Surface smooth. In cross-section the species is flat hexagonal, as can be clearly seen in
apertural views. The youngest chambers are more or less pentagonal in apertural view.
Angles not so sharp as to form a keel. Sutures not distinct, hardly or not depressed, curved.
Chambers gradually increasing in size. Aperture elongate, perpendicular to inner margin
of last formed chamber. The species is very characteristic by its flat hexagonal shape in
cross section.

Cushman had already pointed to the fact that the name U. ^yg-mae« of d\'Orbigny was
often applied to species with striated latest chambers (lit. 58), while d\'Orbigny\'s U. pygmaea
has punctate latest chambers. Cushman did not give a name for the entirely striated species,
but this was lately fulfilled by Hofker, who called it U. mediterranea, because the species
was found at two places in the Mediterranean (lit. 61). Perhaps it was not necessary to give
a new name, because there are certainly species described by authors, synonjmi with U.
mediterranea. However, to avoid errors, it is much better to give a new name to this very
common form than to use one of the old names. It is only to regret that Hofker has not
chosen a better, more general name for this form, so common and wide-spread fossil as well
as recent.

Test with rounded initial end; from initial end gradually widening till about halfway
the length of test where it is widest, then narrowing first slowly, later rapidly, towards the
aperture. Surface fairly smooth, sutures distinct, depressed; course of the sutures very
peculiar. There are only few, high chambers, differing in shape and size. The species is
sub-oval in cross section. Aperture terminal, a rounded neck with minute lip.

This species resembles in its general shape and more or less in the course of its sutures
Uvigerinella parva Cushman amp; Jarvis 1929, but the aperture of U. westermanni is distinctly
uvigeriniform.

Uvigerina cocoaensis, in Cushman amp; Applin, Bull. Am. Ass. Petr. Geol. X, 1926,

p. 174, pi. 8, fig. 15. (not U. cocoaensis Cushman 1925, Contr. Cushm. Lab. Foram.

Res. 1, pt. 3, p. 68, pi. lo, fig. 12, and not U. cocoaensis Cushman, in Cushman amp;

Schenck, Univ. CaliL Publ. Bull. Dep. Geol. Sci. vol. 17, no. 8, 1928, p. 312, pi. 43, fig.

Test sub-oval in cross section. Initial end bluntly pointed. Test rapidly attaining largest
width. Width decreasing near apertural end. Sutures rather distinct, depressed. Chambers
few, high, early chambers irregularly arranged, with indistinct sutures and ca. 17 well marked
costae. Aperture terminal, rounded, with distinct neck.

The Bonaire species is closest to U. oligocaenica Andreae. The latter species is longer and
narrower, more tapering towards the apertural end, with a longer and thinner neck.

U. cocoaensis Cushman 1925 has less and coarser costae. not restricted to the earliest
chambers, though becoming less conspicuous in later chambers and costae of one chamber
usually not confluent with those of adjacent chambers; its sutures are more depressed; it
has a distinct lip and its neck is shorter than in U. bonairensis.

Test biconvex, thick. Chambers few. inflated and rounded, rapidly increasing in size.

with huge last formed chamber. Sutures distinct, depressed. On the dorsal side somewhat
more than one coil is visible. Ventral side involute. Wall coarsely perphorate. Aperture
ventral, not distinct; above the aperture (on the last formed chamber) is a clear white space,
consisting of the largest part of a circle, truncated towards the (apertural) inner margin of
the chamber. At or quite near the border of this white space there are ca. 9 supplementary
apertures.

The find of this species of Baggina is very interesting, in the first place because the genus
Baggina was not yet known in the Eocene, in the second place because supplementary
apertures were not observed hitherto in Baggina species.

1—3. Eponides jacksonensis Cushman amp; Applin 1926, Bull. Am. Ass. Petr. Geol.

Test biconvex, dorsal side more convex than ventral side. Periphery acute. Wall coarsely
perphorate. Dorsal side showing about two whorls; in the last formed whorl there are ca. 6
chambers. Ventral side smooth, involute. Chambers gradually increasing in size. Sutures
on dorsal side rather distinct, not so on ventral side. Sutures gently to strongly curved
dorsally, less curved ventrally. Most specimens have an umbilicus, but it is not always very
distinct and in some specimens it fails. Aperture ventral, nearer to the umbilical part of the
chamber than to the peripheral part. In specimens with a well developed umbilicus,
the chambers have distinct incisions on the ventral side; in specimens where the umbilicus
is not distinct or fails, this character cannot be verified.

The species resembles L. rugulosa Cushman 1926 and L. ocalana Cushman 1926; princip-
ally it differs from both species by its much stronger incisions of the chambers. Ln ocalana has
a more rounded shape.

Most probably the Bonaire specimens belong to S. pulchra: they agree on the whole
with the descriptions, but the figures given are very indistinct. In the Bonaire specimens the
dorsal side is generally slightly more convex than the ventral one; the periphery is subacute,
there is no keel. The wall is coarsely perphorate. Sutures on the dorsal side flush, on the ventral
.side slightly depressed. On the dorsal side the sutures are running strongly backwards. Dorsally
there are at most three whorls visible; the last whorl has about 5 chambers. The peculiar
ornamentations mentioned by Cushman are not distinct on the Bonaire specimens. The
Bonaire specimens are relatively small sized.

Beside the species mentioned in the list on p. 43, there are some other species of
Globigerina in the material. Their variability, however, is so great that I did not
succeed in distinguishing distinct forms. They are mostly subglobular specimens with 4 or 5
large chambers visible, occasionally with some small chambers, resembling species like
G. conglobata Brady or G. quadrilobata d\'Orb.

Test small, planoconvex: dorsal side flat or slightly concave, ventral side conical.
Periphery lobulate, acute, not keeled. There are 2 to ly^ whorls visible on the dorsal side,
with 5 or 6 chambers in the last whorl. Sutures fairly distinct; on the dorsal side flush, curved
backwards; on the ventral side depressed, straight, radiate or nearly so. Surface rough.
Aperture elongate, indistinct, from the umbilical area extending towards the periphery,
widest near the umbilical area.

Globorotalia kochi resembles to some degree G. michelitiiana [d\'Oih.), but it has less cham-
bers in the last coil, the sutures on the dorsal side more curved backward, the periphery
less acute, not keeled, the sutures on the ventral side not curved, a less conspicuous aperture
and a rough surface.

Test small, planoconvex. Sutures distinct on the conical ventral side, not so on the
flattened dorsal side. Surface papillate. Umbilical area depressed on ventral side. In the
last formed coil there are 4 chambers; these are rather individual, especially on the ventral
side, more or less overlapping. On the dorsal side there are little more than 2 whorls visible,
though very indistinct. Aperture elongate, ventral, on inner margin of last formed chamber.

At first sight this species reminds us of G. crassula Cushman amp; Stewart, but it is clearly
different: its periphery is more rounded, its form is generally higher, its chambers more
individual and the coiling is less conspicuous. In not one specimen there are more than 4
chambers in the last formed coil.

Test nearly bilaterally symmetrical, with broadly rounded periphery. Dorsal side
showing 2—2 ^ whorl, with 6—8 chambers in the last formed whorl. Sutures very distinct,
depressed, gently curved. Chambers fairly individual, very gradually increasing in size.
Wall coarsely perphorate. Aperture not distinct, on inner margin of last formed chamber.

The species is very close to A. badenensis d\'Orb., from which it chiefly differs in being
more bilaterally symmetrical, so not having the last formed chamber projecting over the
dorsal side.

Test compressed, planispirally coiled, dorsal side flat, evolute; ventral side concave,
involute. Last formed coil with large chambers, more individual than earlier chambers and
dorsally rising above the flattened dorsal side. Aperture peripheral.

The genus Bonairea is nearest related to the genus Anomalina, from which it chiefly
differs by its most characteristic features: the planispirally coiling, the concave ventral
side, the individuality and peculiar arrangement of the chambers of the last formed coil.

Species of small size, test as in genus. Early chambers close coiled, on the dorsal side
there are ca. 2 coils visible. In the last formed coil there are 5—6 chambers, much larger
and higher than the preceding chambers, more individual and with blunt processes directed
half backward, half dorsal. As a consequence of the size of the chambers of the last formed
coil, the ventral side is strongly concave, the dorsal side is flat, except the prolongations of
the chambers of the last formed coil. Surface smooth. Sutures fairly distinct, slightly
depressed in the early chambers, more so in the last formed coil, curved. Aperture not
distinct, peripheral, possibly with a continuation on the dorsal side.

As a result of the peculiar form of the last formed chambers, the species gives in side
view the impression of a small crown, to which feature it owes its specific name.

(Reprinted from the Contributions Cushman Lab. Foram. Res.
Vol. 9, pt. 2, June 1933, p. 30.)

I am proposing the following new name, Ruttenia, in place of
Bonairea which is already preoccupied.

Bonairea Pijpers, Geol. amp; Pal. Bonaire (D. W. i.), Diss. Utrecht, 1933,
p. 72 (not of H. Burrington Baker, 1924).

The generic name Bonairea has been already used by H. Bur-
rington Baker in 1924 for a subgenus of gastropods (Occ. Papers
Mus. Zool. Univ. of Michigan, vol. 6, No. 152, 1924, p. 42, Genus
Tudora Gray, Subgenus Bonairea).

The genotype of Ruttenia will be Ruttenia coronaeformis
CPiivers) = Bonairea coronaeformis Pijpers, Geo! amp; Pal
Bonaire (D. W. I.), 1933, p. 72.

_ My thanks are due to Mr. P. Hummelinck, biologist, for call-
ing my attention to Burrington Baker\'s name.

Cibicides americanus Cushman 1918, var. bonairensis n. var Fig 130—133
Cibrcides americanus is a miocene form, occurring in Panama; a variety has become
known rom the U. Eocene of Antigua: var. antigua Cushm. amp; Applin 1926. The B^aire variety
differs from C. americanus, var. antigua in having more chambers in the last formed coil
m having the chambers more regularly built and in having a more rounded form It differs
from C. americariushy the same features, by its less distinct, not raised sutures and by the
absence of a keel (this keel, however, is not very pronounced in C. americanus)
Age. Upper. Eocene.

290 X 230 131 ventral view 290 x 230 ja. 132 ventral view 305 X 270 133 peripheral

view 430 X 340 135 dorsal view 315 x 250 136 ventral view 540 x 470 f., 137 periphe-
ral view showing aperture 500 x 290 f.; fig. 138-141 Dyocibicides rutteni n. sp. 138 dorsal

Test planoconvex: ventral side strongly convex, with few large chambers visible; dorsal
side flat or shghtly concave. Wall coarsely perphorate. Sutures distinct, depressed and
slightly curved on ventral side, flush and strongly curved backwards on dorsal side Only
chambers of the last coil (generally 6 or 7) are distinct on the dorsal side. The chambers
have more or less pronounced incisions on the dorsal side. Last formed chamber very large
sized, highly inflated; dorsally rising above the general plane. Peripheral margin acute;
occasionally the ventral side has a gentle rounding towards this margin. Aperture peripheral
Through personal communication of Dr. Thalmann, I was informed that this species
IS common in the U. Eocene of Mexico.
Age. Upper Eocene.

Locality. Well near Porta Spaiio (Columbia Plantation, Bonaire).
Genus Dyocibicides.

Test much compressed, dorsally flattened and more or less evolute; ventrally minutely
convex, only the chambers of the last formed coil visible. Margin acute. Wall coarsely
perphorate. Chambers very irregulariy arranged, closely coiled in the eariy portion; later

chambers with irregular form and irregularly running sutures. Aperture mdistinct. probably
entirely at the ventral side.nbsp;^ ^

(ht. 63) which is defined by Brady\'s fig.7, pi. 93, in lit. 53 (named Truncatulina variabilis d\'Orb
by Brady). In that case it would be remarkable that there is not one specimen with more
series of uncoiled chambers among the Bonaire material, though several specimens
were found.

Fragment of a meandroid form with the valleys united by simple walls. The fragment is
more or less conical, compressed. The lower side of the fragment has a length of 20 mm a
width of 5 mm.; probably the colony was fixed with a narrow elongate base.

Valleys not very sinuous, width 1,5—3 mm., generally 2 mm. Septa rather thick,
36—44 to 1 cm., long septa with thickened inner ends alternating with very short ones. Walls
relatively thick, generally 0,2 mm., in places 0,4 mm. Dissepiments are rather numerous
Costae not distinct.

L. of fragment 48 mm.; W. 29 mm.; H. 44 mm.
Age. Uppermost Cretaceous. Rincon formation.
Locality. W. of Rincon (W. Bonaire).

Coralhtes 5—6 mm., in well developed coenenchyma. There are 3 complete cycles of
septa and an incomplete 4th cycle. Two cycles of .septa reach the columella, the remaining
septa are shorter. These two cycles consist of moderately thick septa, the other septa are
thin. The columella is trabecular, well developed, to 1,5 mm. in diameter. There are costae
corresponding with all septa uniting the corallites. Dimension of intercorallite areas very
variable: distance of two corallites ranging from 1 mm. or less to 3,5 mm. Walls and dissep-
iments are well developed, dissepiments both endo- and exothecal.

The species shows most resemblance with O. brevis (Duncan 1864) of the Nivajd shale,
San Domingo, of unknown horizon. The Bonaire species differs by its equal costae and
development of endothecal dissepiments and by the 2 cycles of thick septa.
Age. Uppermost Cretaceous. Rincon formation.
Locality. W. of Rincon (W. Bonaire).

Small corallites in a varying, generally rich mass of coenenchyma. Corallites mostly
1 mm. in diameter. Distances of corallites 0,5—1,75 mm. I counted 14—19 septa, of which

half the length of the longer ones. Longer septa are thicker than shorter ones. Columella
small but well developed, trabecular. Costae well developed, to all septa. In the wall septa
and costae are thickening.nbsp;^

Species with irregular, polygonal corallites, with distinct wall. CoraUites 3-7 5 mm
chiefly 4 and 5 mm. There are 44-62 septa. In a corallite with ca. 60 septa there are ca\'
15 long septa, ca. 15 shorter ones, the remaining being very short. The long septa are perfor-
ated. Synapticulae generally well developed. Columella trabecular, not strongly developed

The mam differences with S. hilsboroensis are the ill developed columella and few
synapticulae in some corallites.

Smaller corallites have 4 cycles and a few quinaries, larger ones 5 cycles or 4 cycles and
many quinaries. The septa of 3 cycles are thick, of the 4th and 5th cycle thin. Septa closely
arranged, granulated, in the older parts rather thick and united with the columella in the
younger parts thinner, partly united with the columella, partly with distinct pali\' in the
youngest parts (that is in the calices, where there is no columella) partly with pali The septa
are also joined inter se. Near the wall the septa are perphorate. Columella very well developed
trabecular or spongy. Costae rather thick, with narrow interspaces, equal. Probably there
are costae to all septa. Wall porous in the interspaces of the costae; in places, generally being
m the older parts of the corallites, the wall is secondarily thickened. In the latter case the
porosity of the wall is no longer noticeable. There is no epitheca.

I have hesitated a long time whether to bring this species to the genus Balanophyllia
b. Wood or to Palaeopsammia. The genera are closely related. Chief differences of the present
species with Balanophyllia. wherefore it was brought to Palaeopsammia, are: 1 the occurrence
of thickenings at the ends of all septa (pali); 2. the occurrence of numerous shorter septa
generally three shorter septa between two longer ones; 3. junctions among the septa near
tne wall (m Balanophyllia these junctions are more common towards the columella)

Wanner says that in Palaopsammia the septa are not numerous (lit. 67) and conse-
quently are not closely arranged. This character is doubted by Oppenheim (lit 64 p 316)-
moreover. Wanner himself gives for P. aegyptica 5 cycles of septa. Indeed the number of
septa is no generic criterion.nbsp;lt;

The genus Palaeopsammia is known of Palestina and of the Libyan desert (Egvpti in
the Upper Cretaceous.nbsp;\'

Corallum simple, free, short-conical, straight or sub-cornute. Corallites elliptical, with
numerous septa.

There are 4 complete cycles of septa and a varying number of septa of the 5th cycle.
Approximately 3 cycles of septa are long, thick and swollen at the ends. They alternate with
small and thin septa of the 4th and 5th cycle. The pali before the septa are arranged in one
crown. The septa are finely granulated. Columella short and compact, only in the oldest
parts of the corallites and fused with the pali. In the younger parts there is no columella,
the septa are thinner, generally without pali. Wall thick, especially in the oldest parts of thé
corallites, with well developed epitheca.

Only one specimen is present in the material. The species has strongly and beautifully
curved wings, first downwards, then backwards to tlie midline. The shorter axis is 20 mm.
For the other dimensions I can refer to fig. 143. There are ca. 14 septa to 1 cm. The strong
backward curvation, immediately after the downward curving of the wings, is very typical,
and distinguishes this species from all the other Diploctcnium species. The Bonaire species
is nearest to D. haidingeri Reuss and D. conjungms Reuss. It differs from both species by
the strong curvation of the wings. D. haidingeri is bigger and the downwards running branch
of the wings is longer; D. conjungcns is smaller.

Fragment of corallum with a height of 75 mm. The calices generally have a diameter

r f.f ■ f/;? ^Eugyra sp.. much enlarged; fig. 143 Diploctenium sp. dimensions in mm.;
fig. 144, U5Nennea sp.. reduced, fig. 145 showing cavities; fig. 146 Horizontal section
through Terebratula martini n. sp. showing outer socket ridge (o), inner socket ridge fi)
crurum (c), course of loop (1) and hinge tooth (h); v ventral valve with foramen, d dorsal valve!

of 1 mm., the intervening walls are 0,75-1 mm. There are 6 distinct septa and a styliform
columella. Costae 24, 6 prominent and 18 smaller ones.

Hitherto the species was only found in the Oligocene of Anguilla (horizon of Anguilla
formation) and of Panama (Emperador limestone and Culebra formation). The Bonaire
specimen was found in a limestone, occurring among quaternary limestones and I consider
it here to be of quaternary age too.

Corallum forming compressed branches or masses. Scattered over the surface are numer-
ous monticules, generally reaching a height of 2 mm. and generally not exceeding a diameter
of 3 mm. at the base. Calices 0,5 mm., without definite arrangement; distances between
the cahces varying, equal to or exceeding the diameter of the calices. Calices fairly deep
margins of many calices slightly raised. There are 6 septa running to the styliform columella
nearly reaching the top of the calices. Number of costae varying, at least 12- between 2
septa there are 1, 2 or 3 costae. The costae never extend from one calice to the next There
IS no groove, defining the limits of the individual corallites. The coenenchyma is granulated

The species shows some resemblance with 5. monticulosa Hoffmeister 1925 but the
diameter of the calices is slightly smaller. It is also related to 5. panamensis Vaughan 1919
but the diameter of the calices is smaller, the distances of the calices are generally larger
and it never has the indistinct upper lip of the upper wall of the calices.

Calices 1—1,5 mm in diameter. There are 8 long septa, reaching the relatively thick
columella, and 8 shorter ones. The shorter septa are not visible in all calices.

The Bonaire specimen differs only from A. portoricensis by its thicker columella.

A. portoricensis was found in the Oligocene of Antigua (Antigua formation), Porto Rico
(Pepino formation) and Panama (Emperador limestone). The Bonaire specimen occurs in
upper eocene limestone.

The specimen is rounded, 6,7 x 6 x 4,7 mm. There are 10—14 septa, reaching the
columella and a very incomplete cycle of very small septa alternating. Pali are present, the
columella is thick. The Bonaire specimen shows some slight differences with the species
described by Gerth of Cura9ao (Seroe Teintje limestone): 1. the very rudimentary 3rd cycle;
2. there is generally more coenenchyma between the calices than is the case in the Cura9ao
specimens; 3. the columella is thicker than in the Curagao specimens.

The wall of the Bonaire specimen gives a good notion of the quot;geschlossene, ringförmige
Mauerquot; as described by Gerth (lit. 13).

Fragment, 7 X 6,8 X ca. 4,5 mm. Diameter of calices generally 1,75 mm. Septa 24—26.
Septa of the 2nd cycle long and thickening at the free ends, septa of the 3rd cycle short, as
thick as the septa of the 1st and 2nd cycle, but without the thickening at the ends. In places
the septa of the 3rd cycle fuse with septa of higher cycles. The septa are almost as thick
as the interseptal loculi. Distances between the corallites are approximately equal to the
diameter of the corallites. Distances of centres of calices ca. 3,5 mm. The coenenchyma is
chiefly retiform, concentric around the calices. The cavities in the coenenchyma often coin-
cide with the interseptal loculi.

Only one small fragment was found. Calices depressed, 1,5—2 mm. diameter. There are
8 or 9 septa. Columella well developed, Ptrabecular. Between the calices is much coenenchyma
granulated or striated. Distances between 2 calices 3, 3,5 and 4 mm.

There are 2 specimens, both badly preserved. The larger has a diameter of 60 mm, the
smaller of ca. 50 mm. The smaller specimen has a thickness of ca. 32 mm. The species is
involute; the sutures are well marked, S-shaped. The altitude of the whorls is ca. 3 times
their average width from suture to suture. Ventral saddle very broadly rounded, lateral
lobes broadly rounded, lateral saddles relatively narrow and prominent. Siphuncle central.
The Bonaire specimens are close to H. ulrichi, however, the lateral saddles are more rounded
in H. ulrichi and broadly rounded in the younger parts, and, as the Bonaire specimens are
much smaller than H. ulrichi, it is just with the early stages of this species that they must
be compared. H. ulrichi has become known of the Midway Eocene of Trinidad.

The Bonaire specimens also show some resemblance with H. peruviana BeTvy of the
Eocene of Peru.

The material consists of a weathered specimen and a fragment. Top, aperture and details
of sculpture are obliterated. The shell is large sized, conic-cylindric. Whorls wide, height
of whorls ca. 34 % of diameter of shell. The larger specimen, which has 5 whorls, has a length
of 140 mm., largest diameter of 80 mm. Spiral angle 20—25 degrees. There is a single convex
spiral ridge, ca. 30 % of height of whorl. Grooves between the ridges concave, with a faint
indication of 2 spiral threads. Columella solid, ca. 30 % of diameter. There are 4 folds in
the interior; 2 on the columella, the upper one obtuse conical, the lower one larger and higher;
1 on the outer lip, very obtuse; 1 on top of whorl, obtuse conical, somewhat larger than the
upper fold of columella. On the basis of the whorl there are 2 or 3 slight undulations.

The shell of the larger specimen (not of the fragment) has a great many irregular cavities.
On the surface these cavities give the impression of being the result of honeycombe weathering,
but the cavities are inside as well. Some cavities are connected with the interior of the shell.
I do not know whether such cavities have ever been found in the shell substance of gastro-
podes; I consider them as an individual abnormality.

The described species is different from any Nerinea that had become known up till now
of the West Indies and of Central America and, as far as I can judge, of the N. part of
S. America and the Cretaceous of W. Europe.

One ill-preserved specimen was found. It agrees in most features with the short forms
of V. musica. On the inner lip it has 8 strong and 3 minor plaits, consequently 11 plaits in
all. Generally the less attenuated forms of 1\'. musica have 9 plaits, while 11 plaits are only
found in more attenuated forms.

Test thick, oblong, inequilateral. Anterior end very short, posterior end much produced.
Beaks touching, highly inflated, extremely far forward. Anterior side more or less truncated
with rounded transitions to the right and left sides of the test. Posterior side gaping. Surface
sculptured with concentric ribs, narrow and close anteriorly, becoming less conspicuous, wider
and more distant posteriorly. Radial sculpture chiefly in middle portion of valves, very
indistinct in anterior and posterior portion. It is much .less conspicuous than concentric
sculpture and consists of coarse, broad, distant ribs, which pass obliciuely from the umbo
to the margin. I\'osterior dorsal area slightly concave, smooth.

The species iias much resemblance with P. alpina IMatheron. Though P. alpina is rather
varying, however, I did not notice one form that agrees entirely with P. trechmanni. P. alpina
is generally thicker, its posterior side is more gaping, its radial ribs are generally more
conspicuous than the Bonaire species. P. trechmanni is generally more e.xcentric anteriorly,
its anterior surface is more truncate to all sides.

There are 12 specimens in the collection of which 8 are well enough preserved to be
measured.

There are more than 50 specimens in the material, but the greater part of them is mise-
rably preserved.

L. 17,4—36,8 mm.; W. ca. 9—32,5 mm.; Thickness (Th.) 9—24,1 mm; — 87 -ca. 98 %;

Til transv. dm. for.
— 52—69%; transverse diameter of foramen 1,1 —1,6 (?2) mm;-------4 7 %.

Shell suboval or suborbicular, smooth, striated by fine lines of growth, which beconu-
stronger and well marked towards the anterior margin. Ventral valve convex with a slight
carination along its mesial portion from the beak to the anterior margin; near the anterior
margin the valve is more or less compressed. Dorsal valve slightly more convex than ventral
one, with an obscure, slightly raised mesial fold. Anterior commissure uniplicate. The shell
is very finely striated radially (visible in PI. I, fig. 25); the cardinal areas do not .show tlie
radial striae, but they have distinct concentric ones. Beak erect, almost suberect and pierced
by a moderately large, circular foramen. In some specimens the foramen is subcircular, the
transverse diameter being the largest. Hinge-teeth stout, projecting with blunt points.
Cardinal process distinct, rather stout. Crural bases and crura well developed. Loop very
simple, the transverse band strongly arched, crural proces.ses mconspicuous. By the last
mentioned character the species takes a separate position in the genus Terebratula. Also
the fine radial striation is uncommon for the genus, but Thomson mentions that it has been
found in many representatives of the Terebratulinae, where it seems to be \'quot;an old-age
featurequot; (lit. 69, p. 189).

The shape of T. martini resembles T. carneoides (\'uppy of the liocene of Trinidad and
St. Barts, but it is more orbicular and the curvature of the anterior commissure in 7quot;. carneoi-
des is very gradually, while in 7quot;. martini it sliows a sharp bending on both sides of the dorsal
mesial fold.

The material consists of more than 500 specimens, man^\' of them in good
state of conservation. Because I am of the opinion that absolute measures are
of little value and that it are chiefly the proportions between the different meas-

iires that are essential, I have given proportions, as man}\' as I thought necessary.
I add some general remarks about the measuring and some abbreviations.

Average values of periproct and peristome are generally based on less meas-
ures than the other values; those of the petals and apex on le.ss measures than
tho.se of length, width and height.

Peristome. The position of the peristome in species provided with a labruni
was located by measuring the distance quot;labrum-anterior sidequot;. 1. because the
labrum in ill preserved specimens is often well visible; 2. because the measure
quot;labrum-anterior sidequot; turned out to be better achievable than the measure
quot;labrum-posterior side.quot; In the other species the peristome was measured from
anterior side of peristome-anterior side of test.

Periproct. The mea.sure quot;periproct-posterior sidequot; (in species with an infra-
marginal periproct) was taken from the posterior border of the periproct.

Petals were measured in real length, petaloid areas in horizontal projection
(consequently the subtense was measured). Interporiferous areas were generally
measured at widest part of petal.

In my de.scriptions I followed the classification given by Lambert amp; Thiery
in their quot;Es.sai de nomenclature raisonnee des Echinidesquot; (lit. 75).

F,. length of test; \\V. width of test; H. iieight of test; - ■ , • ; — -—--—---;

pet. area: petaloid area; 1. I amp; V .lengtli of petals I and V; w. I amp; V width of petals 1 and V;

w width of petals I and V
ia. 1 amp; V width of interporiferous area of petals I and V; ---Iamp;V —^ —nbsp;.

1. 1 amp; \\\' length of petals 1 and V | width of interporiferous area of petals 1 and V
Lnbsp;length of test \' wnbsp;width of petals I and V

II I 111 w III i:i III—III \'\' — III is conipreliensible; apa.distanceapex-anterior\'

diameter of test); wps. width of peristome (measured parallel to shortest, transverse diameter

of test); psa. distance peristome-anterior side; --ps ---—-----; —----- - TTquot;quot; •

^ -------------------; Ipp. length of periproct (measured parallel to a vertical

plane through the longest diameter of test); wpp. width of })eriproct (measured parallel to

transverse diameter of test); -- pp --- ----7— - i PPP- distance periproct-postenor

1 or 2 specimens of this form as described and figured by Cotteau from Anguilla (lit. 72)
were found on Bonaire. Jeannet, however, is not sure that the species of Cotte.\\u agrees
with that described by Forbes from Malta.

ca. 37 %; ------------ 40 %; diameter of scrobicles 1,5 mm; diameter of tubercles

The Bonaire specimen shows some slight differences with the species of Cottkaxi:
H

1. the proportion —:-is smaller (59 % in Cotteau\'s description) ; 2. the interporiferou.s areas

are not depressed; 3. the interporiferous areas are narrower; the Bonaire specimen has 4
columns of tubercles, Cotteau\'s figures give 6 columns, however, in his description he men-
tions 4 columns; 4. near the median suture of the interambulacra (zone miliaire) the Bonaire
specimen has few scattered tubercles, quite near the median suture the surface is smooth;
in this respect it agrees somewhat with C. loveni.

Among my material a species occurs, which belongs to the suborder of the Clypeastroida
and is nearest the family of the Eoscutidae. However, the species has a sunken peristome,
while IvAmbert and Thiéry give in lit. 75 for the Eoscutidae (p. 287): quot;. . . peristome à fleur
de test ...quot; I therefore propose to change the characterization of the Eoscutidae by adding
to quot;péristome à fleur de testquot;: quot;ou enfoncéquot;. Because the species has no septa and is modera-
tely high, it is closest to the subfamily of the Echinocyamidae, this, however, being sub-
globular. This is only a minute difference and the Bonaire species can be brought to the
Echinocyamidae when we add to quot;subglobuleuxquot; in lit. 75: quot;ou dépriméquot;.

Pas de rosette buccale, péristome à fleur de test ou enfoncé; cloisons simples ou nulles.

Test with subcircular or rounded pentagonal ambitus. Dorsal surface convex, flattened
at the top, ventral surface depressed. Apex central or subcentral. Peristome subcircular
to pentagonal, subcentral. Periproct suboircular, inframarginal, very near the posterior
margin. Petals with unequal pores.

L. 10,9—35,4 mm.; av. L. 22,6 mm.; W. 10,8—33,8 mm.; av. W. 21,6 mm.; H. 5,9—17,8

mm.; av. H. 10,5 mm.; — 90—100 %; av. — 95 %; — 37—59 %; av. — 47 %; pet. area ca.

11,8 X 10,7—28 X 26 mm.; -- 42—74 %; av. --56 %; 1. I amp; V 3—13,2 mm ■

av. 1. I amp; V 7,7 mm.; w. I amp; V 0,8—5 mm.; av.w. I amp; V 2,8 mm.; ia. I amp; V ca. 0,5—2 mm.;

7,4 mm.; w. 11 amp; IV 0,7—4,8 mm.; av. w. II amp; IV 2,9 mm.; ia. 11 amp; IV 0,6(0,3?)—2 mm.;

av. ia. II amp; IV 1,1 mm.; amp; IV 29—55 %; av. ^-j-ll amp; IV 39 %;nbsp;23—43 %;

1. HI 9,0 mm.; w. Ill c.a 1,5—5,5 mm.; av. w. Ill 3,1 mm.; ia. Ill 0,6(0,3?)—2(2,5?) mm.;

av. ia. Ill 1,2 mm.; — Ill 26—45 %; av. Til 34 %;nbsp;31—51 %; av. - 39 %; —

11126—54%; av.—Ill 39%; apa. 5,5—19 mm.; av. apa. 13,3 mm.; --48—57 %;av.—54%;

Ips. 1,3—4,5 mm.; av. Ips. 2,7 nun.; wps. 1,8—ca. 6 mm.; eiv. wps. 3,2 mm.; psa. 5—16 nnn.;

~ 41—51 %; av. 45 %; 1pp. 0,7—ca. 2,5 mm.; av. 1pp. 1,5 mm.; vvpp. 0,9—2,5 mm.;

av. wpp. 1,6 mm.; ppp. 0,5—3,4 mm.; av. ppp. 1,8 mm.; --pp 95—ca. 146 %; av. -ypp 112 %;

Test as in genus, with the ventral surface depressed, subconcave or flat; in the latter
case being somewhat depressed around the deep depression of the peristome. In many
specimens the test shows slight sinuosities, being most pronounced at the ambitus. The
depressions of these sinuosities correspond with the median suture of the interambulacra
and with the adradial suture. The test is very thick. Apical system snuill, madreporic pores
forming a compact button at the apex; 4 genital pores are arranged in a trapeziuni with the
anterior pair approximated, all of the same size. Peristome central or slightly anterior to
the midpoint. Periproct as in geiius, subcircular, slightly wider than long. Ambulacra! petals
unequal, rather narrow, open at the ends, generally more or less costulate. Near the apex the
pairs of pores of one petal are diverging, towards the margin becoming parallel or slightly
converging. Ambulacra compo.sed of simple primary plates, pores uniserial; the plates are
low in the petals and ventrally from the petals as far as approximately halfway the ventral
side where they become higher. Ambulacral pores unequal, the extern ones oblique, the
intern ones rounded, the two members of a pair of pores connected by a groove, following
the suture between two plates. Where the ambulacrum ceases to be petaloid, the pores
become etjual, rounded and disposed in oblique pairs, on the ventral side even becoming

superposed. The whole surface of the test is studded with deep-set small tubercles of appro-
ximately uniform size, more crowded on the ventral side. The mamelons of the tubercles
are set in such deep areolae that they hardly exceed the general level of the test. Interpori-
ferous zones with 2, 3 or 4 columns of tubercles.

Aristotle\'s lantern and auricles. Preserved are pyramids, epiphyses and parts of teeth.
The pyramids are relatively high; in a specimen measuring L: 23,7 mm.; W: 22,7 mm.;
H: 10,2 mm., pyramid 5 measures w: 8 mm.; h: 6 mm.; pyramids 1 amp; 4 are smaller: w: 6 mm.;
h: ca. 6 mm.; pyramids 2 amp; 3 are still smaller: w: 5 mm.; h: 5 mm. The two halfpyramids of
.5 are equal, those of 1 amp; 4 are unequal, the posterior being the largest, the two halfpyramids
of 2 amp; 3 are subequal. The foramen magnum is relatively deep, especially in pyramid 5,
it is shallower in 1 amp; 4, still more shallow in 2 amp; 3; the interior distance of the small epiphyses
is in the specimen mentioned above 2 mm. in pyramid 1 —1,5 mm. in pyr. 1 amp; 4, 1 mm. in
pyr. 2 amp; 3. In the inner part of the lantern the wings of two halfpyramids approach each
other very closely or even touch each other; in the latter case the tooth lies in a sort of conical
tube with a small opening on the lower side. The teeth are nearly triangular with a broad
keel.

The auricles are blunt processes, closely approaching interambulacrad.
The species has been named in honour of Prof. L. Rutten.
Age. Upper Eocene.

Family Echinobrissidae Wright 1856.
Subfamily Haimeidae Lamb. 1931.
Tribe Echinogalerinae Lamb. 1918.

L. 55,6 mm.; W. 54,9 mm,; H.ca. 33,3 mm.; —99 %;ca. 60 %. 1, I amp; V ca. 32 mm.;

w. I amp; V 8,6 mm.; ia I amp; V 4,6 mm.; — I amp; V ca. 27 %; ---ca. 58 %; — I amp; V 54 %;

1. II amp; IV ca. 31,5 mm; w. 11 amp; IV 8,5 mm.; ia. 11 amp; IV 4,5 mm.; y II amp; IV ca. 27 %;

1. II amp; IV ^^nbsp;^ II amp; IV 53 %; 1. Ill ca. 33,5 mm.; w. Ill 8,5 mm.; ia. Ill 4,5 mm.;

y III ca. 25 %;nbsp;ca. 60 %; — III 53 %; apa,ca. 28 mm.; ca. 50 %; ps.?; psa.

(measured from posterior margin) ca. 29 mm.; ca. 52 %; 1pp. ?2,3 mm.; wpp. ?1,9 mm.;

Although the peristome is badly preserved, one can see that it is oblique. The Bonaire
specimen differs from A. merrilli by the following characteristics: 1. nearly flush poriferous
areas; 2. largest width of the petals lies higher than in A. merrilli (higher than halfway

between apex and ambitus); 3. the extern pores are elongate; in A. merrilli all the pores are

round; 4. the Bonaire specimen is higher: — 60 %, A. merrilli — 54 and 55 %. (Clark amp;

According to Lambert and Thiérv (lit. 75, p. 341) A. americanus can be a synonym

of A. merrilli, \'quot;bien (jue plus renfléequot;. 1 calculated the proportion — for A. americanus, but

found it to be smaller than for A. merrilli, viz. 45 %, 40 %, 36 %, 36 %.
Age. Upper Eocene.

Pauropygus ovum serpentis (Gupp\\- 1866). PI. 1, fig. 7, 8.
Among my material there are 24 specimens of P. ovum serpentis, rather varying in their
characteristics. Because 1 have only 24 specimens it has no sense to give average values.

L. 15,7—35 mm.; W. 13,4—31 mm.; H. 8,8—17,5 mm.; — 78—89 %; —45—70 %;

pet. area 15 x 11,9—31 x 27,5 mm.; ------ 62—79 %; 1. 1 amp; V ca, 4,7-14,7 mm.;

w 1. 1 amp;
w. 1 amp; V 2—5,5 mm.; ia. 1 amp; V ca. 1,1 2,3 mm.; — 1 amp; V 28—47 %; - ---28- 42 %;

Ifll amp; V 38—55 %; 1. 11 amp; IV ca. 4,5—13,5 nmi.; w. II amp; IV 2—6 mm.; ia. 11 amp; IV 1, 1—2,5
w

mm.; ^ 11 amp; IV 35-50 %;nbsp;27—39 %; II amp; IV 38- 60 %; 1. Ill 6,5 (?5)-17

mm.; w. Ill 2-5,5 mm.; j III 28(?25)—39 %; \'\'^^^ 35(?32) -49 %; Jj; III 42 60 %; apa
7,8—ca. 19,5 mm.; 50 -58 %; Ips. 2—ca. 3,3 mm.; wps. 2,5—3,4 mm.; psa. 6,5 -ca. 12

(?I5,5) mm.; j p.s. 103--138 %; 10—14 %; ca. 41—48 %; 1pp. ca. 1,2—2,3 mm.;

Some of the Bonaire specimens have flush petals, others do have costulate petals, hut
the poriferous areas are not depressed. It is a fact tliat these specimens do not agree in this
respect with the species of (iupi-v, but at the utmost the differences can be of varietal rank,
because the si)ecimens fall within the range of variation of P. ovum serpentis. Aloreover, the
great variabiblity of P. ovum serpentis is a well known fact: Guri\'v, Cotteau, Jackson,
Sanchez Roig, Arnold amp; Clark and La.mhert have drawn the attention to it.
.\\ge. Upper Eocene.

Localities. SW. of Seroe .Montagne (W. Honaire), SE. of Seroe Dochila (W. Honaire), SW.
of Punta Blanco (W. Bonaire).

l\'quot;amily Prospatangidae Lamb. 1905.
Subfamily Asterostomidae Pomel 1883.
Tribe .^ntillasterinae Lamb.

Only one, damaged specimen was found. Ambulacra 111 and IV are defective, as well
as peristome and periproct.

L. 123,5 mm.; W. 98,5 mm.; H. 71,5 mm.; — 80 %; — 58 %; 1. I amp; V ca. 90 mm.

w. I amp; V 19,5 mm.; ia. I amp; V 11 m.; — I amp; V ca. 22 %;--ca. 73 %; — I amp; V 56 %;

Test very high, from the top, which is slightly anterior to the midpoint, the dorsal side
is gently inclined towards the ambitus; ventral side nearly flat, slightly concave towards
the peristome. Ambitus oval, smoothly rounded anteriorly, posteriorly the ambitus has the
form of a Gothic arch, truncated by the large periproct, which lies in the level of the ambitus.
Apical system excentric anteriorly, not coinciding with largest height of test. Periproct
in and partly under the ambitus, oval with the longest diameter vertical. Peristome slightly
sunken below the oral surface, excentric anteriorly. Petals I and V open, poriferous areas
slightly diverging, somewhat narrowed at the tip, ending ca. 10 mm. above the ambitus.
Angle between I and V small, ca. 30°. Petals II and IV open, poriferous areas first diverg-
ing till somewhat below halfway between base and tip, then converging, and ending nearer
to the ambitus than petals I and V. Petals II and IV running almost in a vertical plane,
neither anteriorly nor posteriorly. The extern pores of all the petals are elongate slits; some
of the crests between each pair of pores are ornamented with 7 or 8 small tubercles, restricted
to the extern part of the crest. The conservation of the specimen is not well enough to see
if there were tubercles between all the pairs of pores. The poriferous areas are minutely de-
pressed. Ambulacrum III not petaloid, very minutely depressed and provided with
very small pores.

A. bonairensis is closest to A. arnoldi Arnold amp; Clark from Jamaica.
The differences are:

1. the apex of A. bonairensis is more excentric anteriorly; the proportion - for A.

arnoldi is 41 %; 2. ambulacrum III is more depressed in A. arnoldi\', 3. petals II and IV of
A. arnoldi are running anteriorly: both poriferous areas of these petals are directed anteriorly;
4. the angle between petals I and Y oi A. arnoldi is larger (ca. 40°); 5. the extern pores of the
petaloid ambulacra of A. bonairensis are more elongate; 6. periproct seems to Jie higher in
A. arnoldi than in A. bonairensis.

Brissoides (Rhabdobrissus) aloysii n. sp. Fig. 154, 155. PI. I, fig. 18, pi. II, fig. 7—9.

The section Rhabdobrissus is distinguished by a subanal fascicle provided with quot;amor-
ces de branches analesquot;. Of the 8 specimens that were found only 2 show the Rhabdobrissus-
character, the others being too much weathered. I suppose, however, that they all belong
to the same species.

The general form resembles that of species like B. antillarum, clevei and alatus. Test
depressed, ambitus oval, evenly rounded anteriorly, truncated by the hind side posteriorly,

but with rounded corners. Largest width halfway or slightly, anteriory. Dorsal side highest
in interambulacrum 5, ventral side slightly convex towards the posterior margin, ending in
an elevated point or ridge quite near the posterior margin; the ventral side is concave towards
the peristome, sometimes the depression begins sideways of the plastron. Posterior margin
vertical or inclined forwardly. Apical system excentric anteriorly, not coinciding with
largest height of test. There are four genital pores, close together, all of the same size, arranged
so as to form the angles of a trapezium. Peristome very excentric anteriorly, transverse, more
or less depressed, with projecting labrum. Periproct at the top of the posterior margin, oval
with the longest diameter vertical. Paired ambulacra unequal, with depressed poriferous
areas. Pores of paired ambulacra rounded, united by a groove. Petals I and V forming a sharp
angle, rather wide, at the tip closed or nearly closed. Poriferous areas evenly curved. Petals
II and IV rather wide, running anteriorly, not quite closed at the tip. Poriferous areas evenly
curved or the posterior poriferous area is nearly straight, bending anteriorly near the tip;
in the latter case the anterior poriferous area is more strongly curved. Ambulacrum III not
petaloid, depressed towards the median suture so as to form a superficial furrow from apex
to peristome; in some specimens the furrow is hardly perceivable. In only one specimen (no. 1)
the pores can be seen in two columns with the pores alternating. Pores small and rounded.
These columns of pores have a length of ca. 8,5 mm.; the distance between the pores is 1,6 mm.
There are two kinds of tubercles; larger, scrobiculated ones, situated on the dorsal side, encir-
cled by the peripetal lous fasciole; on the ventral side situated chiefly inframarginally
and on the posterior ambulacrum. The smaller ones are more crowded; they are smallest in
the area encircled by the peripetalous fasciole.

The subanal fasciole is not sinuated, the branches of the anal fasciole are situated side-
ways of the periproct.

Till now there was only one species known belonging to the section Rhabdobrissus, viz.
B. jullieni Cotteau, a living species from the coast of Guinea. The Bonaire species is very
different from the recent species. The principal differences are: 1. the largest height of
B. jullieni lies anteriorly of the apex (according to the description of Cotteau; in the figure
the difference in height anteriorly and posteriorly of the apex is not striking); 2. B. jullieni

seems to be lower; the proportion — is 39 %; 3. the petals are excavated in B. jullieni]

4. the interporiferous area of the petaloid ambulacra of B. jullieni are extremely narrow;
Cotteau says that the interporiferous area is sometimes entirely failing; 5. the pores are
elongated in B. jullieni) 6. the periproct of B. jullieni is pear-shaped; 7. the branch of anal
fasciole seems to be situated lower in B. jullieni than this is the case in B. aloysii\\ 8. the
larger tubercles, as far as they are circumscribed by the peripetalous fasciole, are much larger
and scarcer in B. jidlieni than in the Bonaire species (lit. 73).

Apart from the Rhabdobnssus-cha.ramp;ct.Gr, the differences with B. cmtillayutn, clevei and
alatus are:

B. antillnrnm: 1. this species has the posterior margin inclined backwards, so that the

periproct is visible in a dorsal view; 2. the apex is more excentric: the proportion -p for

B. antillarum is: 30, 31, 31, 31, 35 %; 3. the petals are more diverging in B. aloysii, resp.
55, ca. 49, 57 (damaged), 55, ca. 54, 56, 54, ?50 degrees; for B. aniillaruin it is ca. 36, 38, 40,
42 degrees.

B. alatus: 1. the apex is more excentric, the proportion - ■ is 32, 33; 2. .Arnold and

Clark mention quot;oral surface flatquot; and quot;peristome flush with oral surfacequot;; none of the
specimens of B. aloysii have an entirely flat oral surface and in most of the specimens the
peristome is sunken.

This species has been named in honour of the negro-boy Aloysius, whom we owe the
discovery of the find-spot of echini SW. of Seroe Montagne.
Age. Upper Eocene.

Locahty. SW. of Seroe Montagne Bonaire), SW. of Punta Blanco (W. Bonaire).
Tribe .Maretinae F-anib. 1905.
(ienus Maretia (iray 1855.
Mareiii sp. HI. 1, fig. 13—15.

Two specimens of a form belonging to the genus Maretia have been found; the preserva-
tion of the specimens, however, is very bad.

Ambulacrum III and periproct are not preserved in one specimen; of. no. 2 only L, and
H. could be measured approximately.

Test depre.ssed, almost flat, dorsal side slightly convex, from the raised antero-posterior
midline sloping towards the rounded margin, ventral side almost flat with narrow, raised
plastron, posteriorly ending in a very conspicuous point. Posterior margin truncated, with
rounded corners. Peristome subcircular with truncated posterior margin. Labrum inconspi-
cuous, elevated above surface of peristome, which is flush with the surface of the test. Peri-
proct supra-marginal. Petals of the paired ambulacra narrow, flush with the surface. Pores
united by a groove; the extern pores larger than the intern ones, slightly oval. Petals 1
and V fonning a sharp angle (ca. 38°), petals II and IV directed anteriorly, forming an angle
of ca. 110°. Near the apex the petals arc rapidly widening, then gradually narrowing towards
the tips, which are more or less open. On the dorsal side the interambulacra 1 and 4 are
provided with large tubercles: on the ventral side large, scaly tubercles are found on the
plastron and on the interambulacra. Smaller tubercles are found on the dorsal side between
the large ones and on the margin. Both specimens have a quot;fasciole en écusson radiéquot;.

		W	H
w	H	T (%)	T	I. lamp;V	w. lamp;V ia. Iamp;V
(mm.)	(mm.)	(%)	(mm.)	(mm.)	(mm.)
ca. 33	ca. 16,5	ca. 82	ca. 41	ca. 14	4	2
	?18,4		?38	—	-	—
1. lamp;V	i^iamp;v w (%)	I IIamp;IV	w. IIamp;IV ia.IIamp;IV ^	IIamp;IV
(%)	(mm.)	(mm.)	(mm.)		(%)
ca. 35	50	13	3,8	ca. I,	7	29
ia. — IIamp;IV w	apa.	apa \'L	Ips.	wps.	psa.	w yps
(%)	(mm.)	(%)	(mm.)	(mm.)	(mm.)	(%)
ca. 46	ca. 16,5	ca. 41	4,2	ca. 6	15,5	ca. 143

Agassizia inflata Jackson 1922. Contr. Geol. and Paleoni. West Indies. Publ. 306
Cam. Inst. Washington, p. 70, pi. 12, fig. 2—4.
The collected material consists of 80 specimens.

L. 12,9—27,2 mm.; av. L. 19,9 mm.; W. 10,9—22,7 mm.; av. W. 17,4 mm.; H. 9,5 —

19,4 mm.; av. H. 14,7 mm.; — 82—95 %; av. — 85 %; —69-83 %; av. —75 %; 1. I amp; V

ca. 3 (?2)—ca. 5,5 mm.; av. 1. I amp; V 1—2,2 mm.; av.w. I amp; V 1,6 mm.; ia. I amp; V ca. 0,3(?0,1)

—0,4(?0,5) mm.; av. ia. I amp; V 0,3 mm.; —I amp; V 30—50 %; av. — I amp;V 40 %; - ^

16—25(?27) %; av.nbsp;^ %; — I amp; V ca. 14 (?7)—27 %; av. —I amp; V 19 %; 1. II amp; IV

ca. 6 (?5)—ca. 13 mm.; av. 1. II amp; IV 9 mm.; w. II amp; IV 0,5—1,1 mm.; av. w. II amp; IV 0,8 mm;

— II amp; IV ca. 5—ca. 12 %; av. —II amp; IV 9 %;-----ca. 34—ca. 52 %; av. -------

43 %; apa. 9—19 mm.; av. apa. 13 mm.; 6i(?58)—ca. 70 %; av. ^ 67 %; Ips. 0,5—1,4

mm.; av. Ips. 1,0 mm.; wps. 2,1-—6 mm.; av. wps. 3,9 mm.; psa. ca 3—8 mm.; av. psa. 5,1

av. -- 26 %; 1pp. ca. 1,3—4 mm.; av. 1pp. 2,5 mm.; wpp. 2,5—ca. 3,7 mm.; av. wpp. 3,1

Beside the characteristics given by authors 1 will draw the attention to the following:
the elevated swollen plastron, more elevated towards the peristome, and the conspicuous
elevations of interambulacra 1 and 4 near the apex.

I have made A. inflata Jackson a synonym of A. conradi on the following considerations.
Clark and Twitchell say that A. conradi quot;is easily distinguished from other species
of this genus by its more elevated upper surface, slightly conical at the apex, and its very
excentric apex posteriorly. The sharp truncation of the posterior surface is very characteris-
tic.quot; (lit. 76).

The proportion — for A. inflata is — (Jackson).nbsp;(Arnold amp; Ci.ark), being resj).

74, 73 and 70 %. Consequently A. inflata falls within the range of variation of A. conradi:
likewise A. conradi it has the quot;more elevated upper surface.quot; And just like A. conradi,
A. inflata is quot;slightly conical at the apex.quot;

The apex of A. inflata is no more excentric than that of A. conradi\', the proportion - —
for inflata is 64 %.

Jackson mentions concerning the posterior surface of A. infl\'.ita: quot;posterior face truncat-
ed, nearly vertical.quot; I can not give exact data concerning the quot;truncationquot;; most of the
Bonaire specimens have the truncated posterior surface inclined forwardly, but in some
specimens it is nearly vertical. The figure give/i by Jackson of A. inflata (lit. 74, pi. 12, fig. 4),
which must be a photograph of the specimen of Cottkau, given in drawings fig. 9 amp; 10,

pi. 6, sliow distinctly a fonvardly inclined posterior surface. The same can be seen in fig.
9, pi. 6 of CoTTKAU, (lit. 72).

To this I can add that we find back all the typical characters of A. conradi in A. inflaia:
the wide, conical form, the anterior curvature of the apical disk to the ambitus, the swollen
plastron, of which the elevation increases towards the peristome, the elevation of inter-
ambulacra 1 and 4 near the apex, the angle between ambulacra I and V.
Age. Upper Eocene.

Locality. SW. cf Seroe iNIontagne (W. Bonaire).
Agassizia sp., cf. conradi (Bouve 1851).

L. ca. 35,5 mm.; W. ca. 30 mm.; H. ca. 23,2 mm.; — ca. 85 %; — ca. 65 %; 1. I amp; V

7 mm.; w. I amp; V 2,7 mm.; ia 1 amp; V 0.5 mm.; -yl amp; V 39 %; — ■ ca. 20 %; —I amp; V 19 %

w. I.IIamp;IV
1. II amp; IV ca. 21,5 mm.; w. II amp; IV 1,4 mm.; -- II amp;IV ca. 7 %; --- ca. 61 %; apa.

The specimen is injured and weathered, peristome and periproct are not preserved.
Probably it is a large specimen of A. conradi.

The specimen is lower than A. conradi: is ca 65 %; the smallest value that I found

for conradi is 69 %. The petals II and IV are longer than in A. conradi-.-------^----- ca. 61 %,

A. conradi to ca. 52 %. The apex is slightly more excentric, the proportion ^ being ca.
73 %.

The dorsal side is somewhat different from A. conradi: more evenly rounded, the
elevation of the petals near the apex is less pronounced, the nod posteriorly of the apex
towards interambulacrum 5 is less conspicuous.
Age. Upper Eocene.

Prenaster jeanneti n. sp. Fig. 156. PI. I, fig. 9—12.
There are 103 specimens in the collection.

L. 11—52,5 mm.; av. L. 29 mm.; W. 9,9—45,2 mm.; av. W. 24 mm.; H. 8,4—ca. 36,9

3j_20,8 mm.; av. I. 1 amp; V 13,1 mm.; w. I amp; V 0,6—2,5 mm.; av. w. I amp; V 1,8 mm.; ia.

w w 1. I amp; V
I amp; V 0,2—1 mm.; av. ia. I amp; V 0,6 mm.; -I amp; V 10—16 %; av. j\\2 %; ----34-51 %;

av. 1. II amp; IV 11,6 mm.; w. II amp; IV 0,5—2,9 mm.; av. w. II amp; IV 1,8 mm.; ia. II amp; IV 0,4
(0,2?)—1,1 mm.; av. ia. II amp; IV 0,6 mm.; y II amp; IV 10—ca. 16 %; av. wll amp; IV 14 %;

1. II amp; IV 32.__48%; av. \'\' ^^nbsp;40%; — 11 amp; IV 28 (22?)—42%; av. — IT amp; TV 34%:

apa. ca. 2, 5—7 mm.; av. apa. 4,7 mm.; — ca. 11—24%; av. - ~ 17%; Ips. 0,9(0,5?) —

3,5 mm.; av. Ips. 2,1 mm.; wps. ca. 2,1—9 mm.; a v. wps. 5,4 mm.; psa. ca. 4—22 mm.;

av. psa. 11,9 mm.; —ps 167—370(420?)%; av. ^ps 262%; ^^^ ca. 6-9(10?)%; av.-i?N%;

^^ 34--52%; av. ^^^ 42%; 1pp. 2,5—11,4 mm.; av. 1pp. 5,8 mm.; wpp. 1,5—6,5 mm.;

Test ovoid, high, rounded anteriorly, truncated posteriorly, so as to give the posterior
margin a high and flat appearance, dorsal side very swollen, obliquely inclined anteriorly,
slightly inclined posteriorly, largest height approximately halfway the length; ventral
side slightly convex. Test very thin. Apical system extremely excentric anteriorly, supra-
marginal, consequenth- not corresponding with summit of test. Probably quot;apex ethmolysequot;
the 4 genital pores in specimens with well preserved apical system with a relative thick
slightly elevated rim. Periproct at the top of the truncate posterior margin, elliptical with
the longer axis vertically, very much longer than wide, above wider than below, getting
to some degree the form of a deltoid with rounded corners. Peristome transverse, labiate,
with projecting labrum, excentric anteriorly. Plastron amphisterne, wide, swollen, ornamented
with scaly scrobiculated tubercles in regu\'ar close ranged, diverging series. Paired ambulacra
unequal, anterior pair shorter, in connection with the pronounced anterior disposition of
the apical svstem directed more or less posteriorly. Poriferous zones gradually widening
away from the apex, at some distance running parallel. Petals open at the ends. Pores
subequal, oval, the extern ones being a \'ittle longer than the intern ones; each pair of pores
is placed in the form of a ,,circonflexequot;, the extern leg being a little longer. The unpaired
ambulacrum 111 is not petaloid and has one straight pair of small pores, .\\mbulacra II
and IV are rapidly descending to the ambitus, but do not reach it.

Outside the interambulacral plastron the granulation is not well preserved, probably
the whole test was quot;.overed with small scrobiculated tubercles.

Fascioles. The marginal fasciole passes under tlie anus, with a sharp pointed bending
towards the plastron, anteriorly passing along the ventral side at some distance of the
peristome, with a gentle nod at the height of the ambitus, lixactly above this nod. conse-
quently just above the ambitus separates the semiperipetalous fasciole first running parallel
to ambulacra II and IV, then bending gently towards the tip of ambulacra I and V, tra-
versing the interambulacrum 5 in an irregularly curved line.

According to Prof. Jeannkt the .species has some re.semblancc with /\'. dfsori Cotl.
and P. montzensis Lamb., but it has a more central peristome. P. desori has more depressed
petals. By its flush petals and extremely excentric apex the species takes a separate
place within the genus Prenaster.

Localities. SW. of Seroe Montagne (W. lionaire), SW. of Punta Blanco (W. Bonaire).

L. ca. 30 mm.; W. 25,1 mm.; H. 20,3 mm.; —ca. 84 %; — ca. 68 %; 1. I amp; V i) 10 mm.;

w 1. IIamp;IV
w. 1 amp; V 1,4 mm.; -y lamp;V 14 %;--^^-- ca. 33% 1. IIamp;IV 15 mm.; w. II amp; IV ca. 1,2

mm.; — II amp; IV ca. 8 %;-------- ca. 50 %; apa 16,5 mm.; -ca. 55 %; width anterior

Test high, subcordiform, broadly rounded anteriorly, dorsal side sloping rather rapidly
anteriorly and posteriorly to the low ambitus. Ventral .side probably slightly convex. Posterior
side narrow^ Ptruncated. Apex somewhat excentric posteriorly, with 4 genital pores, the
anterior pair larger and more distantly. Periproct probably at the top of the posterior margin.
Paired ambulacra very unequal, narrow, sunken in very deep excavations of the test. These
excavations become wider below the general surface of the test. The poriferous areas lie
halfway the bottom of the furrows. Anterior pair of ambulacra straight or nearly straight,
descending towards the ambitus. Angle between petals II and IV ca. 90°. Posterior pair
narrower and much shorter than anterior pair, slightly curved inwards. Angle between
petals 1 and V ca. 30°. Unpaired ambulacrum not petaloid, provided with a deep furrow, the
depth of which decreases towards the ambitus and is very shallow on the ventral side. One
fasciole is preserved, the peripetalous, which very closely follows the petals. This fasciole
is not flush with the surface of the test, but slightly sunken in the petalous excavations,
so as to border these excavations. The granulation of the test is badly preserved; ventrally
there are scaly tubercles, dorsally smaller tubercles.

The species .shows some resemblance with M. atrnpos (Link. 1816). Differences are:

1.nbsp;M. airopos is less elongate than the Bonaire species; the proportion — is 93—100 %;

2.nbsp;.V/. airopos is higher; the proportion — is 74 85 %. The lowest value found for M. airopos

74 %), however, does not differ very much from the proportion found for the Bonaire species.
It is almost certain that more extensive material will annul this difference. (The measures
upon which the proportions are based are taken from A. Agassiz, lit. 70, p. 366); 3. the anterior ,
pair of ambulacra of M. airopos is angular in outline with a part of the posterior edge of the
apical part of the ambulacra projecting over the anterior edge; nothing of the triangular
spaces between the apical parts of petals 11 and IV and the mid-line of M. atropos are to be
.seen in the Bonaire species; 4. the angle of petals I and Vof .1/. atropos is larger, being ca. 65°.
.Age. Upper Eocene.

Locality. SW. of Seroe Montagne (W. Bonaire),
(quot;.eniis Sc/iizi\'strr .Ag. 1836.

The material contains 2 six-cimens tiiat may belong lo .S. subcvUttdricus Cotteau.

1) Only the narrow and very deep furrows could be measured, not the petals itself.

The differences with S. subcylindricus are: 1. general form: 5. subcylindricus is somewhat
lower and longer; Cotteau speaks of quot;forme allongéequot;. The proportion — of S. subcylindricus

is 74 %, 72 %, 68 %; — is 89 %, 93 %, 90 % (measurements from Cotteau, lit. 72, and
L

Jackson, lit. 74). 2. In S. subcylindricus the furrow in ambulacrum III does not reach the
ambitus; in one of the Bonaire specimens (no. 2) there is a distinct though very slight furrow
at the ambitus. 3. the Bonaire specimens have an oval periproct with the longest diameter
vertically. 4. the apex of the Bonaire specimens is slightly more excentric posteriorly; apa
for S. subcylindricus 65 %, 62 %, 65 %, 64 % (measurements taken from the figures given
by Cotteau and Jackson.

The Bonaire specimen no. 2 has the ambitus more angular than no. 1 and than S.
subcylindricus.

Nineteen specimens were found; I shall only give the range of variation, no average
values.

L. 20—ca. 49,5 mm.; W. 18—43 mm.; H. 14,2—32,7 mm.; y ca. 87 -93 %; ~ ca. 65
- 78 %; 1. I amp; V ca. 3,5—11,5 mm.; w. I amp; V ca. 1,4—4 mm.; ia. I amp; V 0,8—1,2 mm.; — I amp;

V ca. 29 -ca.40 %;nbsp;- ca. 18—27 %;— 28—33 %; 1. II amp; IV ca. 7—19 mm.; w. 11 amp;

IV 2—5,8 mm.; ia. II amp; IV ca. 0,6-1,3 mm.; y II amp; IV 25—ca. 35 %; — ca. 35

—ca. 4,5 mm.; wps. ca. 3,8—9,5 mm.; psa. 6—ca. 13,5 mm.; — ps 200—310 %; 7—10 %;

-— 25— ca. 32 %; 1pp. 3,5—8 mm.; wpp. 2,5—5,5 mm.; y pp 52(?50)—71 %; width of anterior

Test high, oblong, largest height approximately halfway between apex and posterior
side. Largest width approximately halfway the length. Ventral side subconvex with slight-
ly raised plastron. Posterior side high, narrow, truncated, vertical. Apical system subcentral
apa

(80 % of the proportions ^ are between 48 and 52 %). Peristome transverse, semicircular

to kidney-shaped, flush with the surface, very excentric anteriorly. Periproct oval with the
longest diameter vertical, at the top of the posterior side. Petals unequal, the anterior ones
being much longer, very depressed. Petals I and V form a sharp angle, ca. 50—55°. Poriferous
areas gently and equally curved. The interambulacrum 5 between I and V forms a prominent
ridge in the midline, from apex to posterior margin. Petals II and IV form an angle of ca.
95—110°; posterior poriferous area almost straight, anterior one curved. Pores of paired
ambulacra slightly oval. Ambulacrum III not markedly petaloid, forming a deep depression
from apex to ventral side; depth of depression decreasing inframarginally. Pores of ambula-
crum III situated sideways of bottom of depression. Large scaly tubercles are found on the
interambulacral areas of the ventral side, attaining their largest diameter (ca. 1.2 mm. in a
specimen 46,6 mm. of length) on interambulacrum 2 and 3. Smaller tubercles are on the
dorsal side; on the margin the tubercles gradually diminish in size. There are 2 fascioles,
a peripetalous one, closely following the petals, and a latero-subanal fasciole. The latter
approximately separates halfway the posterior side of the petals II and IV from the peri-
petalous fasciole, runs with gentle slope towards the posterior margin and passes low under
the periproct.

S. gerthi is related to S. dumblei Israelsky and S. scherzeri Gabb. 5. dumblei is lower and
has a posteriorly excentric apex and the posterior margin is not truncated as in 5. gerthi.
S. scherzeri has a posteriorly excentric apex and the angle between petals II and IV is decid-
edly smaller.

The basis for the geological map furnished the topographical map 1:20.000.
In the Washikemba formation only areas of chiefly diabase and diabase tuffs
and intrusions have been marked separately. The other Washikemba rocks have
been marked together (Washikemba formation: not differentiated). The bound-
aries of the tertiär}\' limestones and of the areas with predominant diabase are
only provisional: in these two cases more exact boundaries could not be given.
The alluvial deposits in S. Bonaire are chiefty coral sands; their boundaries have
for a great part been taken from the topographical map 1:20.000. (On that map
they are marked as quot;dra.slandquot;). Dunes and shingle walls are given with the same
signature; coral shingle is by far predominating.

Because of financial reasons the geological map has not been printed in
colours; everyone who wants to get a better view of the distribution of the rocks
on Bonaire can colour it with little trouble.

1 must point to some inaccuracies in the sections. In the first place concer-
ning the limits of the tertiary limestones towards the Washikemba formation
and quaternary limestones in the underground. These limits could not be given
with any certainty. The second inaccuracy concerns the Soebi Blanco conglomera-
te. There are some complications in the position of the layers (nearly vertical
layers in some places S. of the Seroe Montagne). These complications are not
marked in the section EF, because they are local phenomena. If there is more
faulting in the conglomerate, it may be thicker or less thick than is marked in
the section.

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Wetensch. Amsterdam, 34, no. 2, 1931, pp. 271—279, text figs.

47.nbsp;Vermunt, L. W. J. amp; Rutten, M. G. Geology of the surroundings of quot;St. Marthaquot;
and quot;St. Kruisquot; (Curaçao). Proc. Kon. Akad. Wetensch. Amsterdam, 34, no. 4, 1931,
pp. 558—563, 4 text figs.

48.nbsp;Vermunt, L. W. J. amp; Rutten, IM. G. Some remarks on the geology of N. Curaçao.
Proc. Kon. Akad. Wetensch. Amsterdam, 34, no. 7, 1931, pp. 1028—1031, 2 text figs.

49.nbsp;Westermann, J. H. Over de geologie van Aruba. Handel, v. h. 23ste Nederl. Nat
en Geneesk. Congres, Delft, 1931, pp. 264—265.

50.nbsp;Westermann, J. H. Over de geologie van Aruba. Geologie en Alijubouw Jg. 10, 1932,
no. 14, p. 145.

51.nbsp;Westermann, J. H. Aruba. Feestbundel K. Martin, Leidsche Geol. Meded. V, 1931,
pp. 709—714, with geological sketch-map.

52.nbsp;Westermann, J. H. Geology of Aruba. Diss. Utrecht 1932. Also Geol. Geogr. ]\\Ieded.

In the list of paleontological literature only papers mentioned in the text are inserted.
Foraminifera.

53.nbsp;Brady, H. B. Report on the foraminifera dredged by H.JM.S. Challenger during the
years 1873—1876. Rep. Scient. Results Voy. Chall., Zoology, 9, 1884.

54.nbsp;Cole, W. Storrs. A foraminiferal fauna from the Guayabal formation in Mexico.
Bull. Am. Pal. 14, no. 51, 1927, pp. 1—46, pis. 1—5.

55.nbsp;Cole, W. Storrs. A foraminiferal fauna from the Chapapote formation in Mexico.
Bull. Am. Pal. 14, no. 53, 1928, pp. 200—232, pis. 32—35.

56.nbsp;Cushman, J. A. The American species of Ovthophragmina and Lepidocyclina. U. S
Geol. Surv. Prof. Pap. 125—D, 1920, pp. 39—108, pis. 7—35.

57.nbsp;Cushman, J. A. Foraminifera, their classification and economic use. Cushm. Lab.
Foram. Res. Special Publ. 1, 1928.

58.nbsp;Cushman, J. A. On Uvigerina pygmea d\'Orbigny. Contr. Cushm. Lab. For. Res. 6,
pt. 3, 1930, pp. 62—63, pi. 9.

59.nbsp;Douvillé, H. Evolution et enchaînements des foraminifèrus. Bull. Soc. Geol. France.
(4), 6, 1906, pp. 588—602, pl. 18, text figs. 11—13.

60.nbsp;Gorter, Nettie E. amp; van der Vlerk, I. M. Larger foraminifera from Central
Falcon (Venezuela). Leidsche Geol. :\\Ieded. IV, 2, 1932, pp. 94—122, pis. 11—17.

61.nbsp;Hofker, J. Notizen über die Fotaminiferen des Golfes von Neapel. III Die Foramini-
feren des Ammontatura. Public, della Staz. Zool. di Napoli, 12, fasc. 1, 1932, pp. 61—144,
45 text figs.

62.nbsp;Rutten, .M. (î. amp; Vermunj-, L. W. J. The Seroe di Cueba limestone from Curaçao
Proc. Kon. Akad. Wetensch. Amsterdam, 35, no. 2, 1932, pp. 228—240, 3 pis., text
figs.

63.nbsp;Thalmann, H. E. Nomenklator (Um- und Neubenennungen) zu den Tafeln 1 bis
115 in 11. B. Brady\'s Werk über die Koraniiniferen der Challenger- Expedition,
London. 1884. Ed. geol. Helv. 25, no. 2, 1932 (at press).

(13). Gerth, H. Beitrage zur Keimtnis der mesozoischen Korallenfaunen von Süd Amerika.
— see lit. no. 13.

64.nbsp;Oppenheim, P. Ueber Korallen aus der obersten Kreide Palästinas. N. J. f. Miner.
etc., B. B. 64, Abt. B, 1930, pp. 307—324, pl. 23.

65.nbsp;Vaughan, T. W. Some fossil corals from the elevated reefs of Curaçao, Arube and
Bonaire. Samml. Geol. Reichsmus. Leiden. II Beitr. z. Geol. v. Niederl. W. I. u. angrenz.
Geb. 2, H. 1, 1901, pp. 1—91.

66.nbsp;Vaughan, T. W. Fossil corals from Central America, Cuba, and Porto Rico, with
an account of the American Tertiary, Pleistocene, and recent coral reefs. U.S. Nat. Mus.
Bull. 103, 1919, pp. 189—524, pis. 68—152.

67.nbsp;Wanner, Joh. Die Fauna der obersten weissen Kreide der libyschen Wüste. Palaeon-
tographica 30, 1902, pp. 91—152, pis. 13—19.

68.nbsp;Lorié, j. Fossile :Mollusken von Curaçao, Aruba und der Küste von Venezuela. Samml.
Geol. Reichsmus. Leiden. Beitr. z. Geol. u. Pal. v. Niederl. W. I. u. angrenz. Geb. 1,
1887—1889, pp. 111—149, 2 pis.

69.nbsp;Thomson, J. A. Brachiopod morphology and genera. N. Zealand Board of Sci. a.
Art, Man. 7, 1927, 338 pp, 2 pis, 103 text figs.

70.nbsp;Agassiz, a. Revision of the Echini. Mem. Mus. Comp. Zool. 3, 1872—74, 762 pp.,
94 pis.

71.nbsp;Arnold, B. W. amp; Clark, H. I.. Jamaican fossil Echini; with descriptions of new
species of cainozoic Echinoidea, by H. I.. Hawkins. Mem. Mus. Comp. Zool. 50, no. 1
1927, 84 pp., 22 pis.

72.nbsp;Cotteau, G. Description des Echinides tertiaires des îles St. Barthélémy et Anguilla.
Kongl. Svenska Vetensk. Handl. 13, 6, 1874, 48 pp., 8 pis.

73.nbsp;Cotteau, G. Description de trois Echinides vivants recueillis par le Dr. J. Jullien
sur les côtes de Guinée (Liberia). Congr. Intern, de Zool. C. R. des Séances, Paris 1889,
pp. 281—292, pis. 2—5.

74.nbsp;Jackson, R. T. Fossil Echini of the West Indies. Contr. Geol. Paleont. W. I. Cam.
Inst. W^ash. Publ. 306, 1922.

75.nbsp;Lambert, J. amp; Thiérv, P. Essai de nomenclature raisonnée des Echinides. Fase.
1—9, Chaumont 1909—1925.

76.nbsp;Twitchell amp; Clark. Mesozoic and cenozoic Echinodermata of the United States.
Un. St. Geol. Surv. :\\Ion. 54, 1915.

Fig. 1—6 Bonaireaster rutteni n.g. n.sp., 1 amp; 2 dorsal surface, 3 amp; 4 ventral surface, 4
showing arrangement of plates, 5 profile, 6 interior view of ventral surface
with auricles, and lantern of Aristotle (1 amp; 3 dorsal side, 4 amp; 5 ventral side,
2 exterior side).

Fig. 7. 8 Pauropygus ovum serpentis (Guppy). 7 with costulate petals and not depressed
poriferous areas, 8 with flush petals.

Fig. 9_12 Prenaster jeanneti n. sp., 9 dorsal surface, 10 ventral surface, 11 profile, 12

Fig. 20, 21 Schizaster sp., ?cf. subcylindricus Cott., 20 dorsal surface, 21 profile.

Fig. 22 - 24 Pholadomya trechnianni n. sp., 22 profile, 23 dorsal surface, 24 anterior surface.
Fig. 25—28 Terebratula martini n. sp., 25 ventral surface, 26 dorsal surface, 27 profile,

Fig. 30, 31 Coral belonging to the family of the Turbinolidae.
Fig. 32, 33 Operculina bonairensis n. sp.

Fig. 1—3 Antillaster bonairensis n. sp., 1 dorsal surface, 2 profile, 3 posterior surface.
Fig. 4—6 Amblypygus cf. merrilli Twitchell, 4 dorsal surface, 5 ventral surface, 6 profile.
Fig. 7—9 Brissoides {Rhabdobrissus) aloysii n. sp., 7 dorsal surface, 8 ventral surface,
9 profile.

Fig. 10 12 Schizaster gerthi n. sp., 10 dorsal surface, 11 profile, 12 posterior surface.

Het ware wenschelijk de nomenclatuur van het gebit der Mammalia te
gebruiken zooals voorgesteld wordt door Bolk in zijn z.g. concentratie-theorie.

A. H. Clark heeft verwantschap tusschen de Echinoidea en de Crinoidea
meenen te vinden; de punten van overeenkomst zijn vermoedelijk voor een deel
meer schijnbaar dan werkelijkheid.

Het is logischer de Orde der Bothriocidaroida als de primitiefste groep
van Echiniden te beschouwen en de andere Orden van haar af te leiden, dan
haar als een zijtak te beschouwen.

De door Lameere en anderen aangenomen volgorde in de vorming der
mesenteriën bij Tetracoralla tot en met het Edwardsia-stadium is alleen te
vergelijken met die van de Hexacoralla, als men een afwijking aanneemt van
de ontstaansregel tusschen mesenteriën en septa in de stadia, voorafgaande
aan het Edwardsia-stadium.

Wood Jones heeft bewezen, dat Cocos Island zijn atol-vorm verkregen
heeft zonder dat daling van het eiland heeft plaats gehad.

Het ontstaan van kegel (..Tutenquot;)-structuren in gesteenten is een physisch-
lithoS sch probleem, d.w.z. eenerzijds afhankelijk van de facies van het ge-
iten^ anderzijds van de physische toestand van het gesteente t.dens en na

\'\' quot;D^vTrÏlarmg die R. Hermann voor het ontstaan van kegelstnicturen
heeft gegeven kunnen we in groote trekken als juist aanvaarden; het is Her-
mann evenwd niet mogen gelukken een aannemelijke verklanng te geven voor
alle details van de kegelstructuur.

De verklaring die M. Roesler gegeven heeft van de ijzerertsafzettingen
in Oriente Province, Cuba, is het meest waarschijnlijk te achten.

De onderzoekingen van Branco in het Ries van Nördlingen hebben het
zeer waarschijnlijk gemaakt, dat de aldaar gevonden verschijnselen niet het ge-
volg zijn van glaciatie.

De daling van het Ries-gebied, volgende op de opheffing in het Mioceen,
is niet bewezen. Voor de verklaring der feiten is het niet noodzakelijk, dat we
deze daling aannemen.

Mocht men ooit algemeen tot het inzicht komen van de noodzakelijkheid
van een wereldtaal, dan is het aan te bevelen als zoodanig „Anglicquot; te kiezen
en niet ,,Esperantoquot;.

H.	22	24	ca.	, 22,5	19,9		13,3 ca. 28	32,5	ca. 30,4 mm
W. 17	89	80		79		90		84	85	?79	79 0/^
H. 17	44	52	ca.	57		54		60	ca. 52	?51	ca. 52 %
1. I«S:V	22,3	?20		18	ca.	18	ca.	11	ca. 25	ca. 30	— mm
w. I amp; V ca.	7	6,2		5		5		2,3	7	8	— mm
ia. I amp; V	4	3,5		3		2,5		1.2	3,2	5,5	— mm
w yl amp; V ca.	31	?31		28	ca.	28	ca.	21	ca. 28	ca. 27	- %
I. Iamp; V L	45	?44	ca.	45	ca.	49	ca.	49	ca. 46	—	- %
ia —I amp; V ca. w	57	56		60		50		52	46	69	— 0/ /o
1. IIamp;IV	21	?21	ca.	17,5 ca.	16	ca.	8	ca. 23	26	— mm
w.IIamp;IV	7,3	6		5,7		5	ca.	2,8	6,5	8,7	— mm
ia. IIamp;IV ca.	4,3	3,3		3		3	ca.	1,5	4	6	— mm
w -■IIamp;IV ca. 1 1. IIamp;IV T	35	?29	ca.	33,	ca.	31	ca.	35	ca. 28	34	- %
42	?46	ca.	44	ca.	44	ca.	36	ca. 43	—	- %
ia -IIamp;IV ca. w apa. ca.	59	55		53		60	ca.	54	62	69	0/ A)
21	?18,5	ca.	16	ca.	14,5		8	20,8	—	— mm
apa. ~ ca.	43	?40	ca.	40	ca.	39		36	38	—	- %
Ips.	_	?4		?5		?3,5		—	—	—	— mm \'
wps.	—	?7,5	ca.	7,5 ca.	6		—	—	—	— mm

	w -Iamp; V 1	1.1amp;V L \'	^Iamp;V w	1. IIamp;IV w	IIamp;IV ia. IIamp;IV—IIamp;IV 1
1.	(%) ca. 45	(%) ca. 16	(%)	(mm.) ca. 10	(mm.) 2,8	(mm.) 0,9	(%) ca. 28
2.	49	15	35	11	3	?0,7	27
	1. II amp; IV L	ia —IIamp;IV apa w	apa L	Ips.	wps.	psa.
1.	(%) ca. 41	(%) 32	(mm.) 17	(%) 69	(mm.)	(mm.) 4,6	(mm.) ca. 7,2
2.	46	?23	ca. 17	ca. 69	?2	4,5	ca. 6
	w yps	Ips. L	psa L	1pp.	wpp.	w -J-PP
1.	(%)	(%)	(%) ca. 28	(mm.) ?5	(mm.) ?4	(%) ?80
2.	?225	?8	ca. 25	3,7	2,3	62





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