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PRELIMINARY REPORT
VERTEBRATY. PALEON TOLOGY

LLANO ESTACADO.

E. D. COPE.
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INTRODUCTION.

The Llano Estacado, or Stockaded Plain, as Prof. J. D. Dana proposes
to anglicize it, has long been a locality of note.

Its supposed desert conditions have been stated on many maps, and
few expeditions have ventured across it, consequently little was known
of its real character. With the gradual settling up of those portions of
the State to the east came the steady westward extension of the frontier
line of pioneers, who, coming to the plains, found them well adapted to
grazing, and although the surface water was comparatively scarce, ob-
tained abundant supplies at. moderate depths. Thus, while the region is
still sparsely settled, it is fully demonstrated that this so called desert is
not only well adapted for cattle raising, but that its agricultural possi-
bilities are of high order as well.

The geology of the Llano Estacado has been written of by the geol-
ogists who accompanied the different government expeditions which
touched it at various points. Among the earliest of these was Dr. Geo.

‘G. Shumard, who was geologist of the ‘‘ Red River Expedition’’ under

Captain R. B. Marcy.

He describes the borders of the Llano Estacado as presenting ‘‘a long
line of bluffs six hundred feet high, and composed of horizontal layers of
drift and sandstone, interstratified with white limestone. From the base
of the bluffs to the river the country presented a gradual slope of four
hundred feet.’’ ,

The section which he gives in Plate 10 represents the geological forma-
tion from the river to the top of the bluff. Hesays: ‘‘ The inferior
strata, or those between the base of the bluff and the river, having been
ascertained from numerous observations to consist of gypsum and red
clay.’’ His section shows 425 feet of this material, overlaid by 575 feet
of ‘‘ gray and yellow sandstone, interstratified with thin seams of non-
fossiliferous limestone, and this in turn by 100 feet of ‘* drift with small
boulders.’’ He says of this: ‘‘From the drift I obtained. specimens of»

chalcedony, jasper, granite, and obsidian.’’ *

* Marcy's Exploration of the Red River, Washington, 1854, pp. 168, 169,

4 INTRODUCTION.

The remarks of Prof. Hitchcock on the age of the drift (p. 152) may,
but possibly do not, apply to the Llano drift, since Dr. Shumard does
not mention any of the silicified wood as coming from the drift observed
on top of the Llano.

Prof. Hitchcock says:

‘*T have been lead to suspect that what Dr. Shumard calls drift may
be only a newer portion of the Tertiary strata, although, as already re-
marked, silicified wood is found in almost all the fossiliferous formations.
All of the specimens sent by you, however, with one exception, are dico-
tyledonous. They resemble not a little the fossil wood from Antigua,
and the desert near Cairo, in Egypt, both of which deposits are Tertiary.
One specimen is a beautiful example of monocotyledon, a cross section
showing vessels of the shape of a half or gibbous moon. This fact shows
that the climate was warm enough for trees analogous to the palm tribe to
flourish; yet the great predominance of dicotyledonous forms shows a
close analogy with the existing vegetation of the southern part of our
country; nor is there evidence in these specimens of a temperature above
that now existing in our southern States, since several species of palms
occur there.”’

Captain Marcy himself makes this statement in regard to the same
locality:

‘““The geological formation of these bluffs is a red indurated clay,
resting upon a red sandstone, overlaid with a soft dark gray sandstone, and
the whole capped with a white calcareous sandstone, the strata resting
horizontally, and receding in terraces from the base to the summit.’’ *

Following this expedition came the surveys of the Pacific Railroad
route. In volume II of this report Mr. W. P. Blake reports on the geol-
ogy of the route along the thirty-second parallel from the collections of
the party under Captain Pope. Of the Llano Estacado he says (p. 17):

‘¢ The specimens of the rocks from the Llano Estacado have a general

resemblance to each other, and show the nearly uniform nature of the ©

geological formation. They consist for the most part of light colored,
whitish, or gray calcareous sandstones, with specimens of compact amor-
phous limestone, which resembles the specimens containing the Cretaceous
fossils from the Big Springs. Three or four specimens consist of sand
and gravel united by a calcareous cement, and looking as if these mate-
rials had been exposed to the infiltration of water highly charged with car-
bonate of lime. a < These have a very modern aspect,
and much resemble the sandstones and conglomerates of the Tertiary age.

*p, 00.

initRopUction. 5

Indeed, all the specimens of the sandstones of the Llano are so much like
those of the Tertiary, that if it were not for the presence of Cretaceous
fossils, I would have been led to regard them as of that period.”’

Again he says (p. 21):

‘¢ The drift deposit, which has been described by Dr. Shumard as cover-
ing the rocks of the Llano, may, and very probably does, belong to the age
of the Tertiary; but the materials and facts that were procured by Cap-
tain Pope are not sufficient to warrant any conclusions on this point.’’

In his description of the building stones of the collection, he says of
those from the Llano Estacado:

‘All these specimens have a modern look and resemble the Tertiary
sandstones along the margin of the Colorado desert, where some of the
upper beds are highly charged with carbonate of lime in the form of trav-
ertine, or calcareous tufa.’”’

The survey along the thirty-fifth parallel had with them as geologist
Mr. Jules Marcou. In his field notes, published in Volume III of the
same report, he gives the following section, which he says ‘‘ is the same at
the foot of the Llano:’’

‘¢ White limestone.

‘« Caleareous conglomerate.

‘¢ Limestone. :

‘¢ Sandstone with numerous calcareous concretions.
‘¢ Red sandy marls of the New Red.”’

According to the journal here published, Mr. Marcou at first regarded
the plains as probably Cretaceous, but afterwards decided that they were
Jurassic.

In his Geology of North America* he very fully gives his reasons for
assigning it to this period, which are, the finding of fossils that he con-
sidered identical with European forms belonging to the Jurassic, in Pyr-
amid mountain, which he considers as a continuation of the deposits of
the Llano. He, therefore, colors the Llano as Jurassic in the map accom-
panying his work.

Mr. Blake, who discusses the geology of this line also, differs from Mr.
Marcou, and from his understanding of the paleontological evidence
makes the Plains Cretaceous. He states as follows (p. 80):

*¢ Most, if not all, of these Cretaceous fossils were procured from the
edges of the horizontal strata which compose the extensive table-lands

*Zurich, 1858.

6 INTRODUCTION.

along the route, and they indicate to us the Cretaceous age of the Llano
Estacado.

*¢ Further evidence of this is found in the collection made by Captain
John Pope on the Llano further south, near the parallel of 32.

‘¢ He procured specimens of Gryphzea in the bluffs of the Llano at the
Big Springs of the Colorado, and also on the surface, near the [southern
end of the] sandhills, and these fossils, together with the specimens of the
strata and other evidences, led me to describe the Llano as Cretaceous, in
the report on the geology of that route.

‘¢ The Llano is doubtless continuous southeasterly from these localities
to vicinity of Austin and San Antonio, where it forms bluffs filled with
Cretaceous fossils, already described by Ferdinand Roemer.

‘¢ There is thus little doubt the strata of the Llano Estacado and the
other plateaux along the route, resting upon the gypsum formation, are
of Cretaceous ag®, surmounted, perhaps, in places by more recent de-
. posits.’’*

These Cretaceous fossils were the evidence which carried most weight
with him, although, as we have seen, before he recognized the litho-
logical resemblance of the Llano materials to those of Tertiary age.

He continues: ‘‘ There is much reason to believe that the Cretaceous
strata of the Llano are surmounted by Tertiary deposits over a part of
the Plain. This is indicated by the second line of bluffs, or second step,
seen from the valley of the Canadian. Dr. Shumard also, who examined
the Llano at the sources of the Red River, found a layer of rounded
gravel and pebbles upon the top, which he denominates drift, and which
at some places was found to be about 100 feet thick. Fragments of agate
and carnelian, and of silicified wood, appear to abound in this deposit.
The same pebbly bed appears to be found west of the Sierra Madre, on
the table lands of Zuni and its vicinity. These are in all probability
Tertiary or Post-Tertiary deposits; but as they are not characterized by
fossils, and as their extent is not known, I have not indicated them on
the map.’’

These are the first references of these beds to a Cenozoic age, and they

are based upon as good evidence as any that is adduced in any subsequent
publication prior to those of this Survey.

On the geological map prepared by Profs. Hall and Lesley to ac-
company the report of Major W. H. Emory on the United States and
Mexican Boundary Survey,f a portion of the Llano Estacado is colored

*Pages 79, 80.
+ Washington, 1857.

INTRODUCTION. 7

as Tertiary, but no reference is made to it in the text, owing, as Prof.
Hall writes me, to some delay in the preparation of the map.

He also says:

‘¢ The geological formations and the boundaries between them were de-
termined from the best information I could derive from all sources within
my reach. ;

‘<T had before me all the publications which had reference to any por-
tion of that country, and also the collections of rocks and fossils made by
Dr. Parry and Mr. Arthur Schott. I had, moreover, the aid of Dr.
Parry in giving me his oral explanations of the country passed over and
examined during the exploration. There may have been other sources
which have now passed out of my mind. I * * * absorbed all in-
formation which came within my reach, and did the best I could to ex-
press it upon the geological map.’’

Prof. Marsh, in his description of the Lake basins of the Rocky Moun-
tains, makes this statement regarding the Pliocene lake basins:*

‘At the close of the Miocene, a subsidence took place east of the
Rocky Mountains. <A great Pliocene lake was thus formed directly over
the eastern Miocene basin, having nearly the same boundaries on the
north and west, but extending much further east, and stretching south
nearly to the Gulf of Mexico. It covered an area at least five times as
great as the older lake, while its deposits attained a thickness of nearly
or quite 1500 feet. This lake basin may with great propriety be called
the Niobrara basin, since the Niobrara River cuts through its typical
strata for more than 200 miles of its course.

‘¢ The beds in this basin lie nearly horizontal. They are light in color,
and much more arenaceous than the Miocene below. The upper strata
consist of hard sandstones or calcareous grits, which weather but slowly,
and hence still form the great table lands over much of the area of the
Pasinese * *

‘‘The fauna of this lake basin indicates a warm temperate climate.
The more common mammals are a mastodon, rhinoceroses, camels and
horses, the latter being especially abundant.”’

In accordance with this description of the Pliocene lake basins by Prof.
Marsh, Prof. J. LeConte, in his ‘‘ Elements of Geology,’’ maps the Nio-
brara basin as extending southward over the area occupied by the Llano
Estacado.

* American Journal of Science, vol. IX, January, 1875, p. 52.

+ Map of Tertiary Times, showing outlines of coast and places of principal
Tertiary lakes. Elements of Geology. J. LeConte.

This statement is based on recent advice from Prof. LeConte.

§ intRoDUcTION.

The present report shows how nearly the facts were represented by this
map made by Prof. LeConte years previous to the present investigation.

In the spring of 1887, while the law creating a geological survey was
before the Legislature, Profs. W. F. Cummins and R. T. Hill addressed
that body on the subject of geology. In his address, Prof. Cummins
made the statement, as the result of his investigations, that the Llano
Estacado was the site of a fresh water lake in Quaternary times.

During the next year, Prof. Hill crossed the State in two railroad trips,

one via the Texas and Pacific, in company with Prof. Cummins, west-
ward by Pecos City, passing over the southern part of the Plains;
the other to Tucumcari, crossing the northern border of the Plains.
In an article entitled ‘‘ Notes on the Geology of Western Texas,”’
published in the Geological and Scientific Bulletin for October, 1888, im-
mediately after his return from the West, he says:

‘¢ The surface of the Llano Estacado is an early Quaternary loam, and
a direct continuation of the great plains of Kansas and Nebraska.”’

Similar statements were made by him in other papers, but in none of
them was there any reason given for thus referring the deposits which
was more conclusive than those already offered by Shumard, Blake, Hall
and Lesley, Marsh, Le Conte, and Cummins before him. .

It will be observed that all of the statements, except that of Mr. Mar-
cou, while agreeing upon the fact of the presence of Tertiary or Quater-
nary deposits in the Llano Estacado, are simply based upon the lithologic
character of the materials, and in no case was any positive paleontologic
evidence brought forward to substantiate the assertions.

The actual determination of the age of these deposits is the result of
the work of this Survey.

In the winter of 1889-90 Prof. Cummins, while making his section
across the Permian to the top of the Llano Estacado, found the first fos-
sils in the plains material at Blanco Canyon, Crosby county. The beds
were briefly described in his paper, ‘‘ The Permian of Texas and Its
Overlying Beds,”’ in our First Annual Report (1889) under the name of
‘¢ Blanco Canyon Beds’’ (p. 190), and stated to be later than the Creta-
ceous.

In the same Report the beds are referred provisionally (on account of
lithological resemblance and diatomaceous earth) to the same horizon

—1ee

—_—— -~

ee

——_—s

iNtRoDUcTion. 9

as the upper portion of the Fayette beds as described by Penrose. In the
Second Annual Report the deposits were described more in detail and re-
ferred to the Tertiary. The third year’s field work of the party under
Prof. Cummins was around the Llano Estacado, and much more exten-
sive collections were made, some of which were sent to Prof. Cope for
determination, and he, recognizing their great importance, kindly offered
to visit the localities in person for the purpose of securing more com-
plete collections from the various beds. Arrangements were accordingly
perfected by which he made the trip, in company with Prof. Cummins, in
order that the best possible returns might be obtained.

The results brought out by the report of Prof. Cope, which follow, are
the determination of the occurrence of both Tertiary and Quaternary de-
posits, and that the forms of the Blanco and Goodnight beds not only
present new species, but are strictly intermediate between the Loup Fork
and Equus beds, and, as he says, more strictly Pliocene in character than
any of the interior lake deposits heretofore described.

The paper here presented is therefore of importance, not only as defi-
nitely determining the ages of certain portions of the Plains deposits,
but as a valuable addition to our knowledge of these most interesting
forms of life which were the precursors of those of the present.

For the details of the stratigraphy, location of beds, and other infor-
mation regarding the deposits themselves, reference is made to Prof.
Cummins’ paper on this area, which also forms a part of this Fourth An-
nual Report.

E. T. DUMBLE,
State Geologist

A PRELIMINARY REPORT

ON THE

VERTEBRATE PALEONTOLOGY

OF THE

LLANO ESTACADO.

E. D. COPE.

CEtAP TEIN:

THE VERTEBRATE REMAINS FROM THE DOCKUM TERRANE OF
HE URIASSIC [SYSTEM

The Triassic formation is exposed extensively throughout the entire re-
gion at the eastern, northern, and western bases of the Staked Plains, as
already pointed out by authors. An exploration conducted for two sea-
seasons by Mr. W. F. Cummins has demonstrated that it is not rich in
fossils of any’kind, and that such vertebrate remains as occur are very
fragmentary. In the following pages such as are susceptible of identifi-
cation are described.

The entire red region of Northern Texas and the Indian Territory was
originally referred to the Trias by Marcou. In 1878 I obtained evidence
that the greater part of this area belongs to the Permian terrane, and so
stated in various publications.* During his exploration of 1890, Mr.
Cummins obtained some teeth from the Dockum beds, which were sent me
for identification, and I found them to belong to the Triassic reptilian
genera Belodon, Clepsysaurus and Paleoctonus.f These genera have been
found in the Triassic beds of the Atlantic States. ‘The explorations of
1891-92 added the genera Typothorax and Episcoposaurus, which, with
Belodon, I had previously detected in the Triassic bed of New Mexico.

*American Naturalist, 1878, May.
tAnn. Report Geol. Survey Texas, 1890, p. 423.

12 GEOLOGICAL SURVEY OF TEXAS.

Fragments, probably representing the Batrachian genus Eupelor of the
Atlantic Trias, also occur.

There can be no difficulty in distinguishing the Triassic from the Per-
mian formations, if remains of the reptilian fauna are present; the change
of type was radical, and there are no resemblances between the forms of
the respective horizons.

The lacustrine conditions which I ascertained to have prevailed in New
Mexico also characterize the formation in Texas. I obtained in the
former region the Unio terrerubre of Meek; while Mr. Cummins dis-
covered extensive beds of Unios in the Trias of Northwest Texas, com-
posed of a species to which he has given the name of Unio dockumensis.

The vertebrate fossils are always fragmentary, so that but few of them
can be satisfactorily determined.

BATRACHIA.

As already remarked, fragments of a species of this class are found in
the Dockum beds. They have been found most abundantly near to
Dockum. They consist of fragments of dermal and cranial bones, which
exhibit the regular honey-comb pitting of the Pennsylvania species of
Eupelor. A phalange found also resembles that of the Permian genus
Eryops.

REPTILIA.
BELODON, Meyer.

Fragments of the skeleton of species of this genus are the most abun-
dant fossils found in the Dockum beds. They are, however, generally
scattered and fragmentary. An exception of this condition occurred
near Dockum, where a considerable part of the skeleton of one individual
was found together.

BELODON SUPERCILIOSUS, Cope.

Sp. nov. Plate I.

This saurian is represented by a number of fragments of the skull, in-
cluding the left frontal bone, with the greater part of the postfrontal and
parietal attached in place; fragments of the splenials, quadrates, arches,
etc., with a very few fragments of vertebre—one including the right
half of a centrum; parts of femur, fibula, and other long bones, with
numerous dermal bones and several teeth. These were all found together
in a light gray bed not far from the red bed which contained the remains
of the typical specimen of EHpiscoposaurus haplocerus.*

The dermal bones have the characters of those of the Huropean Belo-

*Proceed. Amer. Philosoph. Soc., 1892, p. 129.

oo.

VERTEBRATE REMAINS FROM THE DOCKUM TERRANE. 13

dons as described by Von Meyer.* They are subquadrate in form and
have a more or less obtuse longitudinal keel in the center, which does
not extend to the anterior or posterior borders. The latter are thinned
out and more or less irregular, while the lateral borders are in the larger
plates furnished with sutures, though of no great thickness. In the
larger plates irregular rugosities extend for a short distance at right angles
to the median keel; in the smaller plates the surface is nearly smooth.
There are a good many small plates without keel or sutural border and
which were evidently isolated in the integument of the animal. No plates
showing spines were discovered.

The left frontal bone is preserved, minus a lamina from the internal
side of its posterior third. Its measurements are one-half greater in any
one direction than those of the Belodon buceros, Cope, and it differs from
that species and the B. kapjfii, Meyer, in the form of its superior surface.
Instead of being plane as in those species, the supra-orbital border is
flared upward so as to divide the frontal surface into three sub-equal
parts, viz., a central flat-bottomed groove, and an oblique elevated
plane on each side of it. The surface anteriorly is strongly irregularly
pitted and ridged, much more so than the B. buceros. The posterior half
is smooth except at the borders. The inferior lateral ridges diverge on
each side to the inferior edge of the postfrontal suture. The latter ad-
vances to the anterior third of the orbital border as in the B. kapfii. The
postfrontal is smooth at the borders, but presents rugosities which gen-
erally run to the parietal border. The latter is rough posteriorly.

The splenial bones unite to form part of the symphysis at an acute angle,
and do not diverge from the latter in the concave line displayed by the
B. kapjfii. Their inferior surface is flattened, and is marked by three lines
of narrow longate fosse. The width of these bones exceeds the depth,
while the reverse is the case in the Hpiscoposaurus horridus.

The best preserved and most characteristic tooth is of the longate type
shown by Meyer to belong to the anterior part of the jaws. Of the diam-
eters of the base, the longitudinal a little exceeds the transverse, and the
two cutting angles separate a little convex interior face from a very con-
vex exterior face. There are a few faint traces of grooves at the base of
the latter. The crown is curved slightly inwards. A second well pre-
served crown is very different. It is shorter, and stouter at the base,
where the transverse exceeds the anteroposterior diameter. The angular
lines are only visible on the apical half of the crown, and the entire sur-
face, except near the apex, is marked with well defined approximate
grooves with rounded bottoms.

The type of tooth first described is characteristic of all Belodons,
_but Von Meyer figures and describes a specimen of the second type

* Paleontographica, Vol, VII, 1859-61.

14 GEOLOGICAL SURVEY OF TEXAS.

which he is unwilling to regard as belonging to another species, as he finds
every gradation between the two forms. As the collection of fragments
of Belodons here described includes remains of but one species, and proba-
bly individual, I can not do better than follow Von Meyer’s example for
the present.

The fragment of femur includes the low trochanteric crest, which is
characteristic of the genus. It is angulate at the middle, the superior
half being directed toward the interior border of the shaft, and oblique to
its axis. The external border of the shaft is much less robust than the
internal border. It has been somewhat expanded above by pressure.
The supposed fibula is a slender bone with an Open sigmoid flexure, and
a want of continuity of the inner or longest concave margin. The
margin from one of the extremities of the bone advances on the flat side
of the shaft and forms the boundary of a surface apparently for muscular
insertion. The only extremity whichis preserved is somewhat weathered.
It is in section an oval, flat on one side. The condyle is simply convex in
both directions.

Measurements.

Mm

Elevation of crown of ungrooved tooth ..........-. ee eee eee eee ee ees 32
Diameters of same at base............--.0008: | ATIVEL OP OSLEXIOR Fact ro
transverse ............-. 9.5

Elevation of crown of grooved tooth...... 2.0.2.0... - cee eee cece enecesees 20

Diameters of same at base.................6. | EAR USE OE ceo ois

TtTANSVELSE,.. 2.22. .0000-. $

Tranverse diameter of left frontal bone at orbit.................0ee00.--- 34
Tranverse diameter of left frontal bone at prefontal ..................+.- 17.5

Thickness frontal at median suture........ Meiaiteieicusasier larcleralerstenetrctekevanel wis's lotare 16

Greatest width between olfactory ridges............. cesses ceeeneceseeees 42

Inferior width splenial at beginning of symphysis.................-....- 37

Length splenial included in symphysis..............-.ceeeeesseeeeeeeeee 135

Diameters of femur at third trochanter....... i ARUCL ODO SUCTA OT ea etn el

ELANSVELSE Sctiitai epeiciels wae 70

Diameters fibula near middle....... Sorepedod 1 CY SIRS I poo aa ae

TLANVETSCR yea = feieteteleleta 21

. teroposterior......... 72

Diameters dermal scute..................005- M

| transverse (estimated)... 78

Thickness of same at sutural margin...........-.....-.-eesee cece eeeeeee 10

Phicloness swath) keel ryetetetevetet ey orctaterereonistere talelsie atteieleveve el vi< (oseyiaie er Siereletiehe nae 27

Diameters of a free dermal bone.............. | enterOp Osten ae

CVANISV.CTSE ie e/acieselserletre 27

Thi chm essiOfi Same iis). a\ck ie areteisretebae are are, Sipe ayeheh seis eueela tus eel eee 8

Diameter of dorsal centrum.................. | werbical Sree amr ae te =

anteroposterior ......... 56

The measurements of the skull are about one-half larger than those of
the B, buceros,

a

VERTEBRATE REMAINS FROM THE DOCKUM TERRANE,. 15

PALASOCTONUS, Cope.

Proceedings Amer. Philos. Society, 1877, p. 182.

This genus embraces the largest known carnivorous Dinosauria of the
Triassic age. Up to the present time the only remains referable to it
consist of teeth. These are of two kinds, the one less compressed and
more elongate, and the other more compressed and less elongate. The
former I have supposed to occupy the more anterior position in the series
in accordance with the characters of the Megalosaurid genera of the Ju-
rassic and Cretaceous ages. This supposition is sustained by the fact
that the two forms of teeth are generally found together. In Zanclodon
Myr., the Megalosaurid of the European Trias, the teeth are of equal size.
The only species known hitherto is the P. appalachianus, Cope (1. c.), from
the Keuper Trias of Pennsylvania. The explorations of the Geological Sur-
vey of Texas, conducted by Mr. W. F. Cummins, in the northwestern part
of the State, demonstrate the existence of two species in the Triassic beds
which outcrop at the base of the eastern escarpment of the Staked Plains.

PALHZOCTONUS ORTHODON, Cope.

Sp. nov. Plate II, Figure 1.

Represented by a single anterior tooth of large size. The axis of the
crown is straight, being curved neither inward nor posteriorly. The in-
ternal face is nearly flat transversely at the base, and is moderately convex
from the middle to the apex. The posterior cutting edge is denticulate to
the base of the crown; but the anterior edge is denticulate for the distal
three-fifths of the length only, although it is continued to the base of the
crown as a not very prominent ridge and a little within the anterior con-
vex outline of the crown. The convex anteroexternal side is marked on
the middle of its length by parallel ridges or folds of the surface, which
are separated by shallow grooves wider than themselves. Their direc-
tion is inwards and upwards, and they are separated by a space from the
anterior cutting edge. This space is marked by transverse concentric
ridges, each of which is a continuation of a longitudinal ridge, and which
curves upwards and then downwards to the anterior cutting edge. More
than half the ridges which lie external to those which are thus recurved
simply disappear at both extremities, and successively becoming indis-
tinct, disappear entirely on the middle of the external face of the crown.
No longitudinal grooves on the inner face of the crown, except a short
one at the middle of the anterior cutting edge. Enameled surface min-
utely wrinkled.

Measurements.

Length of enamel covered Crown ............0cccecee cee ee cee eceeeeeeeeces 55

Diameters of base of crown................-. | SIBLEEOMOSKOR OTs\eh Ia. 2 20
TPANSVETSE we sceec cesses . 20

16 GEOLOGICAL SURVEY OF TEXAS.

This species differs from the P. appalachianus in its straighter form,
and the shorter crenate portion of its anterior cutting edge, both points
of approach to the genus Clepsysaurus. Its peculiar sculpture distin-
guishes it from any of the species of either genus which are known. The
dimensions are about those of the P. appalachianus.

The basal part of a larger tooth, probably of this species, was ob-
tained by Mr. Cummins at the same time and place. Its diameters are as
follows :

Mm
ANtEVOPOSTSLIOM .\cisc nic ciate cists cnieelaleiwie vis 0) chtats) cle ssislelahsterefole/ere.slelafers © sinictelctetetetens 28
RIANSMEVAG™. cf Ae.scesesiocaee levees «iad Wate ine taicinte nis tctatelaye aceite he otis isle soa Sea wen ae

From Paloduro Canyon.

PALZOCTONUS DUMBLIANUS, Cope.

Sp. nov. Plate II, Figures 4-6.

Numerous teeth found at the same time and place by Mr. Cummins be-
long to a species distinct from the preceding, and one more like the P.
appalachianus. The canine-like tooth has an inward curvature, and the
anterior cutting edge is not curved within the anterior convexity of the
crown at the base, but continues as its most prominent line. The enamel
is not plicate. It differs from corresponding teeth of P. appalachianus
in the greater convexity of the internal face. Enamel minutely striate.

The posterior teeth, which agree in relative dimensions with the anterior

one just described, differ in character from those of the P. appalachianus
in several respects. .Their internal face is more convex; there is no longi-
tudinal angle dividing the external face into two unequal facets, and there
isa shallow groove near the base on both sides of both of the cutting edges.
These four grooves are present in two such teeth out of eight, which I
think correspond in their posterior position with those typical of the P.
appalachianus. In two others, probably from a more anterior position,
there are three such grooves. In two others there are but two, while in
two others, whose narrow form indicates the most anterior position, a
trace of but one groove, the anterior external, remains.

The teeth of this species obtained are smaller than the types of either
of the other species, but they indicate a reptile of large size.

Measurements.

; . Mm
Diameters of canine-like tooth .............-. | anteroposterior ....-.-...-- 20
tEANS VISE) a -ijeeieetesele< «<5 17

Diameters of more posterior tooth............ anteroposterior ...........- 22
traMSVerse. ...:-+--.-.---0s 14

Diameters of a superior tooth................ anteroposterior ..........-. 22
VANS VETSC yeas stelny-\> © =1- <0 14

Diameters of a posterior tooth ............... anteroposterior ............ 22,

longitudinal................ 30
ETANSVEUSC swine cigie si + ociceien ed

os —-

_

wit

SUMMARY.

ing list seer the state of our knowledge of ihe verte-
Ss of the Texas ‘Tri

|

i ‘
‘ware

siventerens

STEGOCEPHALI.

| RepTIctra.

? PSEUDOSUCHIA.

CRrocopiLia.

CHAPTERS:

THE VERTEBRATE FAUNA OF THE LOUP FORK BEDS.

Abundant remains of Vertebrata were found in the Loup Fork beds
north of the South Fork of Red River, east of the eastern escarpment
of the Staked Plains. With the exception of a tortoise, these belong
exclusively to Mammalia of the superorder Ungulata. The extreme
rarity of Carnivora and the absence of Glires, are noteworthy features
of the localities examined. Of seventeen species obtained, fifteen are

determinable, as follows:
Species. Determinable.

Pest imate sieve eave wis'suelaig aca: euere a 2 ave shel sie el armas encere thle iter 1
CATT VOLS) Bar oc e cic louse crarsuskeroiquaveveyarcvete Siete ee eee one hee ee 1
ProbOSe1 ian ged <ccteisisiacisiiers'o 9 Waves erctcin = ee me errata eter tant eletotets 1 1
Diplarthra—
PenrisSsOdacty lar. ais ais a.crersa'~tevcrsve a step orev aleanentauey terete a taterste 9 9
INEGTO MACE YE. ~ayeia se eiarereverencictersrinteiere vin tree etree aay tekeveyee setae oe 3
17 13

Of the determinable species, two are new to science. All the others
are species hitherto found only in beds of the Loup Fork terrane, thus
fixing conclusively the age of the Texas bed. Much light is thrown on
the structure of many of these species by the new material obtained which
is now described in part.

It is evident that the locality at which the fossils were obtained was
haunted by droves of three-toed horses and camels, with not a few mas-
todons. At one place a space of several acres was thickly strewn with
bones of these animals; and smaller tracts similarly covered were numer-
ous in the same neighborhood. ‘The animals were of all ages, and one of
the most interesting results of our expedition was the obtaining of the
bones, skulls, and teeth of young animals with the deciduous dentition
well preserved.

PROBOSCIDIA.
TETRABELODON, Cope.
Proceeds. Amer. Philos. Society, 1884, p. 2.
American Naturalist, 1889, p. 193.
TETRABELODON SERRIDENS ? Cope.

American Naturalist, 1889, p. 205, figure 8; Mastodon serridens, Cope,
1. c. 1884, p. 524; Plate III, figures 2, 3,

aa? mere e

gy

tepginegyen *etcgas
Poe

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 19

IT refer to this species with much reserve a last inferior molar, which
is for the most part in excellent preservation. It resembles the inter-
mediate molar on which the species was established in most respects, but
presents some important differences, among which is a relatively infe-
rior size. The fact that the last molar exceeds very little in length the
typical intermediate molar, renders the identification doubtful, unless it
indicates a small race of the same species. I provisionally adopt the
latter view.

The molar referred to supports only three crests and a well developed
heel. These crests are elevated, with their apices contracted both longi-
tudinally and transversely. The usual median fissure divides each crest
into an internal and an external half, of which the former is obtusely
serrate or tubercular, and the external expands anteroposteriorly toward
the base, were it supports one or more small tubercles which obstruct the
transverse valleys. There is an external, but no internal cingulum. The
former extends round the external half of the anterior base, where it is
coarsely crenate. The robust external anterior cusp, in place of an an-
terior basal tubercle, sends downward and inward a wide ledge, which
passes cingulum-like round the base of the internal cusp to the inner side
of the crown. In the characters so. far enumerated this tooth resembles
the typical specimen. The differences are as follows: In the new tooth
the internal half of the middle cross-crest has three tubercles; in the type
there are four (one smaller). On the external half of this crest there is
no tubercle besides the main cusp; in the type there is one, in line with
four of the other half. The new tooth shows a single tubercle behind
the main external cusp; in the type there are two. The posterior crest
has in both teeth three tubercles on the external half; on the internal half
there are three, besides the principal in the type, and but one in the new
tooth.

In both teeth the internal part of the first cross-crest is not serrate.
In the new tooth the heel consists of three obtuse tubercles, of which the
external is the largest. The valley separating it from the crest in front
is not blocked by a tubercle. Enamel smooth.

Measurements .

, Mm.
otal lengthy on Crowne ee tag cael. see see ein css cs sme bet oc cede ce 140
Width: of crownratmimst Chests iscmincs «0c cmie cine sacs alse sc. ce taice ces ols 80
Wiidthiof crownat seConmaCKesti. incite slo ede cs sees aware sclicatecvecrivee. 76
Wadth of crown. ‘at thindtenest asso cen che a cick otis ia siom eice ne hinaie ideeees 68
Wadthiofapex of finstkenestmemm sm osr celiac Graciela de. cute chasse sicicly scans ara s 49
Wardthtorapex Of thindicnestrewmrasemceniascemiiicns vincis6 oi cle.e-cee seleeee ew ose cs 36
Hevation of first crest from CiMB WM Piece ce sc sce cece -avevecececces 46
Elevation of third crest from cingulum ................. 00.0 ec cece ee eeeeee 43

As already remarked, this tooth is relatively smaller than the corre-

20 GEOLOGICAL SURVEY OF TEXAS.

sponding one in the type specimen should be. The latter should meas-
ure about 205 mm., whereas the length of the tooth now described is
only 140 mm. It may pertain to a different species, but for the present I
refer it to a small race of the 7. serridens, under the name of T. serridens —
cimarronis.

This tooth was found alone, but other remains of Mastodons are not
rare in the formation, some of them indicating large individuals.

DIPLARTHRA.
APHELOPS, Cope.

Proceeds. Amer. Philos. Society, 1873, p. 520.

Remains of this genus we found to be rather rare, but three individu-
als having come under our notice. ‘Two of these are represented by badly
damaged teeth, not yet determined, while another is represented by a
skull of the species mentioned below.

APHELOPS FOSSIGER, Cope.

Bulletin U. S. Geol. Survey Terrs. 1878, p. 382; Amer. Naturalist,
1879, 771h., figs. 3 and 6; 1887, p. 1006, fig. 22.

A skull of this species was obtained, which does not differ from those
previously known from Nebraska and Kansas.

PROTOHIPPUS, Leidy.

Proceedings Academy of Philadelphia, 1858, p.56, name only. Ex-
tinct Mammalia of Dakota and Nebraska, 1869, p. 275, first description.
Cope, Bulletin U. S. Geol. Survey Terrs., No. 1, Jan., 1874, pp. 10-15.

Merychippus, Leidy, Proceed. Phila. Academy, 1858, 27 (defined),
partim. Extinct Mammalia Dakota and Nebraska, 1869, 292 (deciduous
dentition).

Parahippus, Leidy, op. cit., 1858, p. 26; Extinct Mammalia, etc., 1869,
314 (deciduous dentition).

Hypohippus, Leidy, op. cit., p. 26; Extinct Mammalia, ete., p. 311 (de-
ciduous dentition).

Protohippus s. Merychippus, Leidy, Report U. S. Geol. Survey Terrs.,
Ato., I, p. 322.

Interior columns of the superior molars amtea to the inner crescents,
their worn sections forming loops of the internal border of the crescents.
Second and fifth digits present on both limbs and of reduced size. Bi-
cipital groove double. Metapodials without trochlear keel anteriorly.

The genus is like Hippidium in dentition, and like Hippotheriwm in the
structure of the feet. Its principal distribution is North American, where
it is confined, so far as yet known, to the Loup Fork beds,

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 21

History. Dr. Leidy did not define this genus until 1869, several years
after he had named it. At an earlier period, and in the same paper in
in which the name Protohippus was first used, Dr. Leidy named
and described a supposed genus Merychippus, of which the type was
M. insignis. Leidy afterwards questioned the distinctness of the two sup-
posed genera, and placed the name Protohippus first in joining the two.
Coinciding with this view, I place the name Merychippus in the position
of synonym to Protohippus, although the name first mentioned was the
one first published with a description. This course I believe justifiable
when the names are those of the same author. In this instance the very
objectionable name Merychippus has been suppressed with the apparent
concurrence of the proposer.

So far as the characters go, those of the superior molars were pointed
out by Dr. Leidy. As these are not sufficient to distinguish the genus
from Hippidium, Dr. Leidy at a later date combined the two genera.
My discovery in 1873 that Protohippus possesses three toes like Hippothe-
rium proved its claim to distinction to be valid.

This genus is represented by a good many forms, which have an extensive
range in size, from the P. placidus, said by Marsh to be two and a half
feet in height, to P. mirabilis, Leidy, of about the size of a quagga.
Specific differences are also seen in the form of the anteorbital part of the
maxillary bone, which presents in some of the species one or more fossze
of various sizeand position. The forms of the teeth are much alike, and
the enamel plates present complications in but few species, and then to a
less degree than is found in various species of Hippotherium.

Important changes take place in the pattern of the molar teeth with the
advance of age and prolonged use. The folds of the enamel disappear,
so that the borders of the lakes which are plicate in the young become
perfectly simple in old animals. The period at which the folds disappear
differs in different species, coming earlier in the larger species as a rule.
The time of simplification differs also in different individuals of the same
species, as for instance in the P. placidus (see under that species below).
In some of the species the anterior inner column (protocone) remains dis-
tinct from the anterior inner crescent (paraconule) for a longer time than
in others. In the P. placidus and P. lenticularis the union does not take
place until half of the superior molar is wornaway. ‘This gave rise to the
supposition that the younger individuals of P. placidus represent a species
of Hippotherium, which was named H. gratum by Leidy, who, however,
expressed doubts as to its validity. I have examined the specimens of
the various species of Hippotherium in my collection, with a view of
ascertaining whether any others would enter the genus Protohippus on
continued wear, but I have failed to detect any except in the cases of
isolated teeth. This occurs sometimes in molars of species of the group

De ee GEOLOGICAL SURVEY OF TEXAS.

II (Stylonus) of Hippotherium* When the first premolar and third true
molar of the Protohippus perditus are but little worn, the protocone is
distinct as in Hippotherium, but this state of affairs lasts but a short time.

The temporary superior molars in this genus and Hippotherium resem- -
ble somewhat the permanent molars of Anchitherium. That is, the para
and metaconules are not united longitudinally on the middle of the crown,
but are in line with the protocone and hypocone respectively, and are
more or less connected with them. Leidy refers to the deciduous molars of
what is probably a species of my Sec. II of Hippotherium, under the
name of Merychippus insignis}; and to those of a species of Protohippus,
under the name of Merychippus mirabilis.{ Both belong to species in
which the lake borders are more or less plicate, but it is not possible at
present to determine accurately the species to which they should be re-
ferred. Deciduous teeth of species with more simple enamel borders
have been referred to distinct genera under the names of Parahippus,
Hypohippus, and Anchippus.§ Those on which the first two names were
established were suspected by Leidy to belong to the temporary dentition.
It is probable that they belong to the Protohippus, while Anchippus may
pertain to a species of Hippotherium.

In my private collection is a fragment of the left maxillary bone of the
young horse from the Loup Fork bed of Colorado, which contains a per-
manent molar just protruded, and the crown of a temporary molar about
to be shed. ‘The species is probably the Protohippus perditus of Leidy,
which was abundant at that locality. The deciduous crown is very sim-
ilar in most respects to those figured by Leidy as Merychippus mirabilis.
Another fragment of the right maxilla from the corresponding horizon in
Wyoming, contains three deciduous molars and the alveolus of the single
root of the first. These molars resembie the one described by Leidy as
Hypohippus affinis, but presents a greater degree of wear. In the second
(anterior) tooth the paraconule sends forward no process towards the
metaconule,thus agreeing with Leidy’s type. The third tooth possesses such
a process, thus resembling the type of Leidy’s Anchippus. In the fourth
tooth this process is present and is confluent with the metaconule as in the
permanent dentition. All of these teeth are considerably worn, and the
protocone is confluent with the paraconule in all of them. In Leidy’s
type of Anchippus the protocone remains distinct, and, to judge from his
figure, considerable trituration would be required to bring about a fusion.
Hence it may be that the latter tooth belongs to a species of Hippotherium.

* A review of North American Species of Hippotherium, by E. D. Cope, Pro-
ceedings Amer. Philos. Soc., 1889, p. 429. See Plate II, figure 15; first true
molar of H. calamarium.

+ Extinct Mammalia Dakota and Nebraska., Plate X VII, figures 3 and 4.

{ Op. cit., Plate X VII, figures 10 and 11.

§ Op. cit., pp. 311, 312, 313; Plate X VII, figures 7-13.

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 23

The Wyoming molars resemble closely the fragmentary specimen fig-
ured and described by Leidy as Anchitheriwm australe,* which was found
in Washington county, Texas, in the southern central part of the State.
It was found in association with an superior molar of the Protohippus per-
ditus, according to Leidy, and very probably is a deciduous tooth of that
species. The Anchippus brevidens, Marsh, is also apparently founded on
the deciduous molars of some species.f

The Geological Survey collection contains the almost perfect cranium
of a colt which was found at the same limited locality as that which pro-
duced the Protohippus pachyops and P. fossuldtus; and from its characters
I suspect that it belongs to the former species. The molar teeth; which
are all present (four in number), resemble closely those described by Leidy
as Parahippus cognatus, differing only in their considerably larger size,
This is true of the last tooth of the series, while the others resemble more
nearly the Hypohippus affinis. There can be no doubt then that these
supposed genera were founded on milk teeth of Protohippus. The speci-
men of P. cognatus described by Leidy belongs to one of the medium
sized Protohippi, as P. labrosus, etc., while H. affinis belongs to one of
the larger forms.

The material at my disposal which represents this genus consists of
numerous specimens from Nebraska, Kansas, Oregon, Montana, and Texas.
Of the ten species here adopted, seven are represented by private collec-
tion, and six were obtained by the party of the Geological Survey of
Texas, under the direction of Mr. W. F. Cummins, in the northwestern
part of the State.

The species may be distinguished by the following characteristics.

I. No preorbital fossa.

Lake borders at first plicate; true molars 85 mm.; facial

eae MNM TOA OP) SE «yw allel och cies ale oo 'S kates Gh = Aiea weal af e!ai a ots P. pachyops
Lake borders at first plicate; true molars 61 mm.; principal

premolars 67 mm.; fourth premolar one-rooted........... P. perditus
Drie bles Ae craks ai 2c tele cs ens LES CAI OIE MRO Ogee CIE P. medius
True molars 44 mm.; principal premolars 45 mm.; enamel

Stump spinner ence ee cies Sick doc geal cia assidlee s ¢la wie esas ave P. parvulus

II. A small preorbital fossa well anterior to the orbit.
True molars 69 mm.; enamel simple, facial ridge obtuse... P. fossulatus
UI. A large preorbital fossa closely approximated to the orbit.
True molars 55 mm.; principal premolars 62 mm.; slightly
plicate in the young; premolar one-rooted; facial ridge
AUC ULE, sahelioicc! eis: oa ERR EE ERE er ete clay cc) Seu sec iste we as P. sejunctus

*Report U.S. Geol. Survey Terrs., I, 1873, p. 250. Plate XX, figure 19.
tAmer. Journal Science and Arts, VII, 1875, p. 254.

94 GEOLOGICAL SURVEY OF TEXAS.

True molars 72 mm.; principal premolars 80 mm.; fourth
premolar one-rooted; facial edge acute............ »....P. mirabilis
IV. Preorbital region unknown.

Principal premolars 59 mm.; fourth Bao! enamel sim-
ple} paracone cylindric: «10. anya. bese bestbee cmb. (0TOsUS

Lakes transversely okeanaad borders peas but ee,
special loop of the anterior lake; internal columtis small,
subcylindric: molars 21 by 23 mm...... Heueslt cla cd etre d. < s saemCaMUly

Lakes narrower; borders plicate in young; the 1658 of the
anterior long persistent; internal columns with oval section;
erown averaging lox? mm. i246 en eee ce eat P. placidus
In the species in which that part of fie cranium is known, there is a

longitudinal fossa above the position of the preorbital fossa, extending

along the adjacent parts of the nasal and maxillary bones. That is, it is

present in the P. pachyops, P. fossulatus, P. sejunctus, P. insignis, and P.

mirabilis.

Species in which the protocone does not unite with the paraconule
until late in life, are the P. placidus, P. lenticularis, Cope (described in
the supplement to this chapter), and P. supremus, Leidy, Ext. Mammalia
Dak. and Nebr., p. 328, pl. X XVII, figs. 3, 4.

Before decribing the species contained in the collections made by the
Geological Survey of Texas, I enumerate the species, and offer such re-
marks on them as may be appropriate.

Prorouiprus PpACHyors, Cope, sp. nov. infra.

Prorouirrus perpitus, Leidy, Extinct Mammalia of Dakota and Ne-
braska, 1869, 275, pl. XVII, figs. 1, 2 (young adult); Report U. S..Geol.
Survey Terrs., I., 1873, 248, pl. XX, fig. 16. Parahippus cognatus, Leidy,
Extinct Mammalia, etc., p. 311, pl. X XI, figs. 7-10 (unworn deciduous
molars). Protohippus profectus, Cope, Proceed. Amer. Philos. Society,
1889, p. 447, pl. II, figs. 9-12.

Of this species the most important specimens in my collection are the
following: Two right maxillary bones with full sets of molars of adult
but not old animals from northeast Colorado, collected by myself; part
of maxillary with four molars and a part of the skeleton from north-
ern Kansas, Dr. R. H. Hill; nearly all the molar teeth of both sides, with
considerable part of skeleton from Hitchcock county, Nebraska, F. Hazard;
right maxillary bone with facial region and four molars, from same local-
ity and collector; numerous loose molar teeth of another individual, same
locality and collector; numerous isolated molars, mostly from Colorado.
Deciduous dentition, part of the molar series from northeast Colorado,
E. D. Cope; entire series in maxillary bone from Laramie Peak, Wyo-
ming, J. C. Isaac.

‘

-_

a

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 95

Prorourprus mepius, Cope, Amer. Naturalist, 1892, 944.

Protohippus insignis, Leidy, Cope, Bulletin U.S. G. Survey Terrs. 1874,
No. 1, p. 13; Annual Report do., 1873 (1874), p. 523. Merychippus in-
signis, Leidy, part, Extinct Mammalia Dakota-Nebraska, 1869, p. 296, pl.
XVII, fig. 5. Hujus operis, pl. XVIII, fig. 5.

In the uncertainty as to the species to which Leidy’s typical specimen
of deciduous dentition should be referred, I give this species a name as
above. It is probably the animal described by Leidy as the adult at the
later reference above cited. It is a smaller species than the P. perditus,
with simple enamel plates of the lake borders. My collection contains a
considerable part of a skeleton with incomplete skull of an old individual
with four worn molar teeth from northern Kansas, by Dr. R. H. Hill.
The facial portion of the skull is preserved and it presents no anteorbital
fossa. I figure (pl. X VIII) three molars in a fragment of a maxillary bone
from Cottonwood creek, Oregon, collected by Dr. J. L. Wortman. A
single superior molar from Tehuichila, Vera Cruz, agrees with this species’

Protoniprus pARvuULUS, Marsh, Amer. Jour. Sci. Arts, 1874, p. 251;
Equus parvulus Marsh, op. cit., 1868, p. 374, vol. XLVI.

Isolated teeth from Hitchcock county, Nebraska, F. Hazard; and speci-
mens mentioned below, q. v. Probably referable to P. placidus.

PROTOHIPPUS FOSSULATUS, Cope, sp. nov. infra.

Protourrrus sesuNcTuS, Cope, Bulletin U. S. Geol. Survey Terrs., 1873

(1874) I, p. 15; Annual Report U.S. G. Survey Terrs.,1873 (1874), p. 524;

Amer. Naturalist, 1887, p. 1071, fig. 39. ?° Merychippus insignis, Leidy,
2dspecimen, Extinct Mamm. Dakota-Nebraska, p. 299, pl. X VII, figs. 8-9.

Of this species I have the skull with mandible and entire dentition,
with considerable part of the skeleton of an individual obtained by my-
self in northeast Colorado, with a nearly entire mandible, and fragments
of other individuals from the same locality; a nearly complete skull with
dentition and a considerable part of the skeleton from Deep river, Mon-
tana, collected by J. C. Isaac. This species is about the size of the P. me-
dius, and is considerably smaller than the P. mirabilis, to which it is
related.

PROTOHIPPUS MIRABILIS, Leidy; Cope, Bull. U.S. G. Survey Terrs., I,
1874, p. 15; Leidy Extinct Mamm. Dakota-Nebraska, part, 1869, pp.
299, 327, pl. XVII, figs. 10, 11, 12 (exclus. figs. 8, 9); ?Protohippus su-
premus, Leidy, op. cit., p. 328, pl. X XVII, figs. 3, 4.

The only material which has come under my observation was obtained
in ‘Texas, and is described below. As already remarked, one of the speci-
mens referred by Leidy to this species and figured (figures 8, 9, plate
XVI) by him, represents probably a large and old individual of the P.
sejunctus. It was afterwards concluded by him, and so stated in the Re-
port U. S. Geol. Survey Terrs., I, 1873, p. 322, to be probably the P.

26> > GEOLOGICAL SURVEY OF TEXAS.

perditus; but it differs from that species, as Leidy had already shown, in
the deep preorbital fossa. On the other hand, the molars referred to a
species under the name of P. supremus are appropriate in size and char-
acters to the form whose deciduous molars form the type of Leidy’s origi-
nal description.

PROTOHIPPUS LABROSUS, Cope, Bulletin U. S. Geol. Survey of Terrs.,
I, 1874, p. 18; Ann. Report U. 8. G. Survey Terrs., 1873 (1874), 523,

Represented in my collection by a right maxillary bone which contains
the five anterior molars, with which was found a nearly complete mandi-
ble containing nearly all the molars, with the canines and incisors. The
form of the preorbital region can not be distinctly made out. The species
differs from the P. sejunctus in the close contiguity of the canine and incisor
teeth, which do not present a short diastema, as in P. sejunctus. In its
measurements it is smaller than the P. perditus, and the enamel borders
of the lakes are more simple than in either that species or the P. sejunctus
at the corresponding age. Northeast Colorado.

PROTOHIPPUS CASTILLI, Cope. Proceeds. Amer. Philos. Society, 1885,
p- 151, fig. 2;

mone esented by a single superior molar tooth in my collection from the
Miocene clays of Tehuichila, Vera Cruz, presented to me by Dr. Santiago
Bernard. This tooth is about the size of that of the P. perditus, and
differs from corresponding ones of that species in the relatively greater
transverse extent of the crown, proportionately greater width of the lakes,
and smaller size of the internal columns. The opposed lake borders
are folded as in the corresponding stage of P. perditus, but the loge of
the anterior lake is not so well defined.

Proronippus pLacipus, Leidy, Extinct Mammalia Dakota-Nebraska,
1869, pp. 277-328, pl. XVIII, figs. 39-48; X XVII, figs. 6, 7; Cope,
Bulletin U. S. Survey Terrs., 1873 (1874), (exclusive of bones of skele-
ton). Hipparion gratum, Leidy, op. cit., 287pl. XVIII, figs. 25-30.
Hippotherium gratum, Leidy; Cope Proceeds. Amer. Philos. Society,
1889, figs. 16, 17.

Represented in my collection by molar teeth from Northeast Colorado
(E. D. Cope) and Dundy county, Neb. (F. Hazard). It is the most
abundant species in the Loup Fork bed of Donley county, Texas, as will
be described below, with the P. parvulus, the smallest species of the
genus.

PROTOHIPPUS PACHYOPS, Cope.

Sp. nov. Plate XI, Figure 1; Plate XII; Plate XVII, Figures 2, 3.
Represented by a cranium with lower jaw, from which have been
broken away all posterior to the orbits, and all anterior to the second pre-

molars. 8
The malar-maxillary ridge is obtusely rounded, and there is no pre-

VERTEBRATE FAUNA OF THR LOUP FORK BEDS. yA)

orbital fossa. There is an oval maxillo-nasal fossa, which is strongly pro-
nounced. The infraorbital foramen issues above the middle of the first
true molar. The maxillary bone projects about half the diameter of the
last molar tooth posteriorly to it, but this dimension may increase a little,
as the animal is not fully grown. ‘The anterior orbital border marks a
point above the middle of the last superior molar. The last superior
molar is just protruding from the alveolus. The first and second molars
are worn. ‘Their crowns have a greater anteroposterior than transverse
diameter, and the section of the protocone is greater longitudinally than
transversely, although its junction with the paraconule is complete. The
enamel of the lake borders is simple, except that that of the posterior
wall of the anterior lake presents the usual loops well defined. The su-
perior molars have the crowns long and well curved transversely. In the
inferior molars the anterior and posterior lobes of the metaconid have
but little anteroposterior extent, and the paraconid and hypostylid are
well developed. The column of the last inferior molar, which forms
the heel, is quite small.

Measurements.
Mm
Length of maxillary bone to-anterion border of Pym. 1. ...6. 4) 06. .0s 0.00% 127
Length of ditto from orbit to preorbital foramen.......... 0.2.0.2... .0eees 64
Anteroposterior diameter of true MOlarS............ ccc ee cece ces e eee eenes 84
Mindicterof crown of NL. i... AMLELOP OSL TION a cypnicie\eis/elelsssicleusislaieleie'ss << «16 28
IBLAMISWSLSChrenmyci sins stout aysqry siaverclisveloiehelievsie) sinie seid, « 25
Length of crown of inferior true molars ............. 0... cee e cece ence eee 88
Length of crown of last inferior molar............... cece cece ee eee ee eees 30
Di PCreOL Nie. | ANVEGOPOSLERUOM ware cversrevales/elaels cic ales e)aeievals 31
IGFANOIS GUE) Beco agodds on pono. auOdod TOUndd BoC 13
Denpotmanans ateiromt OL Mi I.) srejeje neice oss cc vice earache. codes caeulesaccee 46
Depth of ramus at posterior end of M. ili...... 0.0... . cece cece ce eee 67

Found by myself in the Loup Fork bed of Donley county, Texas. Mr.
W.F. Cummins found the nearly complete skull of a colt at the same
locality in which the above cranium was found, which from the character
of its facial region and the dimensions of its teeth I can only refer to this
species.

In its general form the skull exhibits the character of immaturity in the
relatively large size of the brain case and orbits, and contraction of the
muzzle and occiput and zygomatic foramina. The profile of the brain case
is convex, descending rapidly posteriorly to the occiput. There isa feeble
sagittal ridge originating from feeble, posteriorly converging temporal
ridges. The sagittal ridge becomes a crest, and immediately divides into
two lateral occipital ridges or rather angles, which include between them
a triangular space with a doubly convex posterior margin, the inion. This
heart-shaped area is longer than wide instead of wider than long, as in
adult animals. The occiput is low, and has a median vertical angle, on

28 GEOLOGICAL SURVEY OF TEXAS.

each side of which it is concave, the superior part of each concavity being
horizontal from the overhanging of theinion. The occipital condyles are
remarkably small: The zygomatic foramen is only about one-fourth as
wide as the interorbital space. The superior orbital border is very promi-
tient anteriorly, and is deeply openly emarginate posteriorly. The an-
terosuperior protuberance is bounded by a notch of the anterior orbital
border. There is no malomaxillary angle, nor preorbital fossa: There
is, on the other hand, a very large nasomaxillary fossa, with a rather
abrupt inferior border, which rises anteriorly to a point above the in
fraorbital foramen. It is separated anteriorly by a narrow bony isthmus
from a deep but small premaxillary fossa. Extremities of the nasal and
premaxillary bones broken off. The infraorbital foramen issues above
the anterior part of the penultimate deciduous molar.

The mastoid and basioccipital elements have fallen out, leaving clean
the sutural surfaces of the squamosal and exoccipital. From the appear-
ance of the latter it seems that basioccipital has no share in the composi-
tion of the condyles. The petrosal, as in the genus Equus, is divided
into two parts by a horizontal suture. The inferior portion is more pro-
duced inferiorly than in the horse and quagga, presenting an angular
ridge downward, which runs forwards and inwards and sends off a trans-
verse branch posteriorly. The tympanic is separated from it bya groove,
and diverges outwards and backwards from the postglenoid process, with
which it is in contact at the interior extremity. The postglenoid process
has considerable transverse extent, and its free border is directed down-
wards and inwards, but it is not produced into a process at this point, as
in the Protohippus mirabilis and the Equi. The maxillary bone is pro=
duced posterior to the last molar about the length of the latter, and pre-
sents an obtuse angle into the zygomatic foramen. An angle of the first
permanent molar is visible at afracture. The palatal notch extends to op-
posite the metacone of the second molar.

The cusps and crests of the teeth are more acute than in the unworn
teeth of the permanent dentition. ‘The internal cusps are connected with
the external cusps by oblique crests, which terminate opposite the ridges
which form the anterior boundaries of the paracone and metacone. ‘The
metaconule is continuous with the hypocone in all of the molars, while the
paraconule is swollen anteriorly, so as to make an emargination with the
protocone in front. The trihedral hypoconule is large and isolated. It
is concave posteriorly in the first and third molars. The parastylid of
the first molar is larger than in the others and is more produced ante-
riorly, as in the permanent dentition. It sends a strong cingulum in-
wards along the anterior margin of the crown to the anterior base of the
protocone. In this tooth the metaconule sends a process towards the par-
aconule, which it does not reach by a wide interval. This process is

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 99

wanting from the two other molars. In this point this tooth resembles
the tooth described by Léidy as Anchippus,; whilé the two others ate
identical in all xespects with his Hypoliippus: The first molar is rela-
tively small, as in the permanent dentition, but it differs from the latter
in haviiig 4 strong internal crest, which is nearly as elevated as the ex-
térnal, and is separated from it by a deep fossa.

Measurements.

e Mm.

Total length of skull preserved from imion............ sees rete eee ee eeee 290
From inion to posterior border of orbit (axial) ............----ee eee ee ees 115
From inion to infraorbital foramen. ......... 0. cc eee cece eee erence eens 242
Horizontal diameter Of Orbit... . 0.2... cece cece cece eee cree tee ceesence 48
Width of skull at zygomatic arches .........-. cece e ieee reece eee e tees 124
Width of skull between middle of orbits ........... 2.6. cece e eee eee eee eee 81
Length from inion to palatal notch..............ee cece eee cece e tree eee 210
AVVAECUEMIM DEN OWE LS) Wey Wert lere ie scne ic sctous\ x sy oile) cyeliolelereterehesehs eleyehaleie els\el4) a's) o)ni‘w\s\efalsie/ elle we 44
Waidthi below? at fromt.Of We MV .c.,5.6 ccc osc een see co cscs cole sieojecaes 56
VV CE OMA vue rat) wIewulaccetecisic:s cre cls, cfevelevaisvearslele wliele) eie)ieiesleGeientavess)ieveleie’ «letsieein 14
Width of palate at D. m. iv posteriorly........... 0 cee eee cece eee e eee eee 32
4 ib ANCELOPOSLELUOM we neste vicliel= cine cers leinlels els\lele siecle 16
Diameters of D,m.i..... ETATES VEL SCR era tae ee eo ea alae 14
ye ‘ ANHEVOPOSUE TOM tereicralea) <feyele tsyereiotsielteis)-|selabale sie. oe 33
Diameters of D. m. 11... 1 IHAUREWORSS bo coggasgoubascabacoddconac qn sunanden 27
e : AMECLOPOSGELIOL cre siicnere i ciele = laeieine wc sins vice ms 30
Diameters of D.m. iv... | ADSENSE s G4 odd GSeedcegoesaoa8 © doo cdo suaaduede 28

Excepting in the case of the first molar, the dentition is much simpler
than that of the adult, and is identical, each tooth taken by itself, with
that of the genus Anchitherium. Their almost unworn condition is espe-
cially favorable for the exhibition of this resemblance.

PROTOHIPPUS PERDITUS, Leidy.

Plate X, Figure 2. For synonymy see above.

A single fragmentary superior molar is the only indication of this spe-
cies which was obtained by the Survey from the locality of Donley county.
It is evidently not common at this place during the Loup Fork epoch,
contrary to what obtains in more northern regions, where it is the most
abundant species.

PROTOHIPPUS PARVULUS, Marsh.

Plate XI, Figures 1, 2. For synonymy see above.

I found superior molar teeth of this species at three localities; one of
the specimens consists of the maxillary bone of the right side, with all the
molars except the fourth premolar in place. The animal is adult, as the
anterior lake of the first true molar is obliterated by wear. The enamel
border of all the lakes is simple, except that there is a loop on the poste-

30 GEOLOGICAL SURVEY OF TEXAS.

rior border of the posterior lake of the last superior molar. The facial
plate of the maxillary is not preserved to the orbital border, but ex-
tends sufficiently near to show that there was no preorbital fossa.

Measurements.

Mm

Potal length of (six MOMS. io. gs inte so ines ne ose ase eels ls a 89
Hhength Of: true MOlars ... oy, lie eeiecasjoiy ieee leiersic ositl vistos cue gic «1 elete elec reece eae ee 44
Diameters: Of Mic vous ee ee steak | anteroposterior .........+4 14
transverse........ meeiehaerersyes 18

Length: of grinding face of Pom aii seeds cee eae ciel so eee 19

The measurements of the other molar teeth are a little less than the
above. In one of these two superior molars are in place in the jaw.

I can not help suspecting that this species will turn out to have been
established on teeth of the P. placidus in an advanced stage of wear. I
discuss this question more fully under the head of that species.

PROTOHIPPUS FOSSULATUS, Cope.

Sp. nov. Plates V, VI, VII.

Represented by a cranium, which has lost all posterior to the posterior
frontal region and anterior to the premaxillary border, found by Mr. W.
F. Cummins in the Loup Fork formation of Donley county, Texas.

The dimensions of this species are superior to those of any other mem-
bers of the genus excepting the P. pachyops and P. mirabilis. It equals
the former and is a little exceeded by the latter. The characters of the
lateral facial fossze are peculiar, and as they are exactly alike on both
sides of the skull, I believe them to be normal. There is no fossa imme-
diately in front of the orbit, but there is a narrow and deep maxillonasal
fossa, whose posterior extremity approaches nearer to the superior part
of the orbit than any other. Beneath it, and immediately above the
penultimate molar tooth, is a small but well pronounced fossa, which is
about as large as would be produced by an oblique impression of the end
of the thumb in putty. Immediately anterior to the infraorbital foramen
is a wider and shallower fossa. Anterior to this is a fossa directed ob-
liquely downward and forward, as a continuation of the nasomaxillary;
and below and in front of this one isa deep concavity of the alveolar
border. :

The posterior wall of the orbit is transverse, throwing the border
outwards. The malomaxillary ridge is prominent, but is obtuse below
the anteorbital region, and the small preorbital fossa, below whose an-
terior border it terminates; that is above the first true molar. - The posi-
tion of the infraorbital foramen is elevated, and is above the anterior
border of the first true molar. The anterior border of the orbit is above
the posterior border of the last superior molar,

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 31

The general form of the skull is cameloid, in the compression of the
nasal region, and the expansion at the orbits superiorly and posteriorly.
The supraorbital foramen is entirely intromarginal and is above the pos-
terior part of the orbit.

The maxillary bone continues posterior to the last molar tooth, one
and a half times the length of the latter. The palate is of moderate
width, and contracts gradually forwards, becoming narrow posterior to
the canine teeth and expanding slightly to the latter. The palatal notch
extends as far anteriorly as the posterior border of the penultimate molar,
and possibly a little further, as its anterior border appears to be notched,
but whether this is normal or not is uncertain. The palatine foramen
enters opposite the posterior borders of the penultimate molars. The
pyramidal processes approach each other posterior to the maxillary bones,
‘thus narrowing the nareal trough.

On one side of the skull the five posterior molars are well preserved.
The space for the third premolar is shorter than in the P. insignis, and I
can not find an alveolus for the fourth, but its position appears to be oc-
cupied by osseous tissue. In P. insignis this tooth is distinct. The
grinding faces of the crowns are wider than long, excepting that of the

last, where the proportions are reversed. The protocone is large and-

well fused with the protoconule, and it is rather more prominent in-
wards than the hypocone, which is not distinct in any of the teeth. The
enamel borders are perfectly simple, and there is no loop between the
protocone and hypocone. The dentition is not that of a very old ani-
mal, as the lakes of the first two molars are perfectly preserved. The sec-
tions of the roots of the canines show that they were of moderate size.

The free extremities of the nasal bones are short and acute, and the
nareal fissure terminates above the position of the fourth premolar, were
it present.

Measurements .

Mm

Length from posterior border of orbit to extremity of nasal bones......... 235
Diameterstatoupiteec sam cecida)s<cisciis aalssicases 1 SRST ODOR IEMON 2... - oe
VCTULC A erencreyeyasere ciciiesevetekere 53

W idth of trontiatmiddlerof Orbite 2.0. eeclelesslccce cde cs dees cot otl uel cdeed 120
Width of nasal bones above infraorbital foramen........................-: 28
Width of nasal bones at nareal fissure.......... 00.00.00 cece eee cece eneeeee 35
Length of free part of masal bones .............0. ec cee ccc cece eee eee e aes 25
Length of maxillary bone to canine. ..............ce ccc cee ev ec eee cee sees 227
Length of maxillary posterior to M. ifi..................0000 cece ee eee eee 47
Width of posterior at extremity of maxillaries...................0. 00 ee eee 24
Width of posterior at end of last molar........ aq ggosaes co nadbindS MAB eD Uae 35
WWALOGIKOL pall ate’ at = MIS ae pease ememeycdey hepa arses teres siete ote iatesar opus ote tcl -wasié. de erasabovere le 50
Width of palate posterior to canine............0.. 0.0... cece cc ce ene ee ees - 26

Diameters of M.i.......... ccc. ccc weecees anteroposterior ........... 20
transverse ..............65 25

82 GEOLOGICAL SURVEY OF TEXAS.

Dismieters Of Mie elas ae ce ee ee anteroposterior............ 27

. GEAMSV.CLSC.calare tte eleis ee e\sretelore 24
Votaldjength of molar, series! .....25..05.. beer ee ee ser eeesetarvois care 145
Length Of rue Molary oo icc oes wa os wie pote nee ete eae ne eae ee 69

The skull of this species indicates a species rather smaller than the ass.

PROTOHIPPUS MIRABILIS, Leidy.

Plates VIUI, IX, Figure 1; X, Figure 4. For synonymy above.

As already remarked, this species was founded on a part of the max-
illary bone of a young animal which contains the last two temporary
molars. The crown of a permanent molar was removed from this frag-
ment and figured by Leidy. This fragment belongs to one of the largest
species of this genus, and it agrees in dimensions and in its large preor-
bital fossa with a nearly entire cranium obtained by Mr. W. F. Cummins
in Donley county.

This cranium lacks only the anterior part of the premaxillary bone, and
the basioccipital. The parietal region is crushed on one side. But one
zygomatic arch is perfect. The size is about that of the ass. The an-
terior border of the orbit marks the posterior border of the last molar.
The malomaxillary ridge is prominent and acute, extending as far for-
wards as the infraorbital foramen, which is above the middle of the first
truemolar. The preorbital fossais large and deep, and is separated from
the orbit by a space two-fifths the width of the latter. In the P. sejunctus
this space is only one-fifth the orbital diameter, while in the P. fossulatus
the fossa is as far in advance of the orbit as its entire diameter. The
nasomaxillary fossa is distinct, is continuous posteriorly with the preor-
bital fossa, and extends anteriorly to the infraorbital foramen. The latter
becomes posteriorly a shallow fossa which extends anteriorly to above the
anterior part of the third premolar. A rather deep fossa behind the line
of the canine alveolus. The free portion of the nasal bones is acute, and
is relatively longer than in the type specimens of P. fossulatus. The
nasal fissure extends to above the anterior border of the root of the fourth
premolar. The maxillary bone projects posteriorly to the last molar once
and three-quarter times the diameter of the latter. The maxillary bones
are somewhat crushed together, so that the dimensions of the palate are
not determinable. The nareal notch extends to opposite the front of the
last superior molar. The postorbital bar is subtransverse, the free border
projecting forwards and outwards. The zygoma is short, its length equal-
ing the space from the superior border of the orbit to the posterior border
of the preorbital fossa. The glenoid surface is wide, and the postglenoid
process has a rather posterior position, and short diameter. Paroccipital

process lost.
The fourth premolar has a single robust root. The third premolar is

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 33

accuminate anteriorly. Excepting in this tooth and the last true molar,
the molars have at their rather advanced state of wear a greater transverse
than anteroposterior diameter. ‘The last molar is strongly emarginate
posteriorly. In all, the protocone is more prominent inwards than the

‘hypocone. The enamel borders are everywhere perfectly simple.

Measurements.

Mm.
Total] length of incomplete Skull ...... 2. ... cee ee eet ence recess eee 390
Length from extremity of nasal bones to posterior border of orbit....... 265

Length from extremity of nasal bones to posterior border of preorbital
OSS AMINA ate eee telofutericisrale' a ect aveucinte enacaaletabs) </als: ove se ras) stataus suersia cietete:els eretate 187
Longitudinal diameter Of Orbit....... 0... ce cece cece tere eee eeeeeee 60
Longitudinal diameter of zygomatic foramen.................00..eee eee 62
Vertical diameter of skull at front of orbit............... cc eee ee ee eee 110
GEM OVO fed EMA SETICS! eye celetatelsicleye e1siaiciors) oleic sia\nla elt -alofaiesvo: el w/e) sio\ejaislaielelel isle 155
NG emMort MON MM EMMLO ATS Hs otsle peter jacks ils) a) ara cle! Giae\<)fellate n/a: arajulatcyopsi etn)» a,eleSlelbie(aleieys 7
Wiomactere(of PMs Wis. ooo. ecu seeaeneneee’ | SIBUCTOBORSLETAOT 5 eos 3d
LT ADSV.ELSChiejnsicfelesivielereyaeie 26
IDIAMEbETS Ob Mls iie. sa sasis oe se raies) e/olele care te) eielereieye anteroposterior. ........ 3
transverse .............. 30)
DyiseigterayotaNil Winer i Aare t ube ete 2's CHEN OMONTUR ENO E ROR 8 a
DE ANISMCLSE irerelatelelielelctelel<r= 20

This species is only inferior in dimensions to the P. pachyops. The
molars have a smaller anteroposterior diameter than in that species, and
the maxillary bone is produced much further posterior to them. The
wide difference in the preorbital region separates this species from the
P. fossulatus. Besides this, the muzzle is more produced, and the free
portion of the nasal bones is more elongate.

The measurements of the teeth of this species agree sufficiently with
those given by Marsh for his Pliohippus pernix,* and the ‘‘ deep irregular
fossa’’ in front of the orbit, and simple enamel ridges are found in both.
Marsh, however, says that the skull is ‘‘ comparatively short,’’ while that
of the present animal is elongate. If the P. mirabilis shall be ascertained
to have no lateral digits, it must be transferred, with the P. pernix, to the
genus Hippidium, Owen.

The anterior part of the skull of a colt containing the entire temporary
molar dentition of both sides, presents the proportions of this species.
Their transverse diameter is “smaller than in the worn temporary molar
of the P. perditus from Colorado already referred to, but this may be duc
to a less degree of wear. As the wear has, however, progressed beyond
the earliest stages, this may be questioned; but as the dimensions and
enamel pattern are appropriate, I refer it here provisionally.

The protocone and hypocone are, in the first (anterior) molar, conflu-
ent with the paraconule and metaconule respectively. The same occur:

* American Journal of Science and Arts, VII, 1874, p. 252.
3—Geol

34 YEOLOGICAL SURVEY OF TEXAS.

in the second molar, but the junction of the protocone is by a very nar-
row isthmus. ‘The third molar resembles the second in the narrower
connection of the protocone with the paraconule. The lakes are isolated
in all three of the teeth, and the anterior presents the usual loop posteri-
orly. The adjacent enamel borders of the lakes have in addition a deep
inflection. The anterior border of the anterior lakes has an inflection
also in the first and second molars, but there is none on the posterior
border. The cementum is well developed. First tooth small, with an
external crest and internal cusp.

Measurements.

Mm

Lene thiol series\Ok temp onary, wOlans pe aires eet timed eieiesltelensiaretencisiaierieieialatciels 85
Diameters of D).\M, Weonads sce aciele ste seahorse / amberoposterior «+s. +0e 102 9
TLANISVELSE ME A Gauss cio ee a

Diameters:of Dem iilace wae cows aoe anteroposterior ........... 30
LE ANIVICUS Cercieehagekaterseleetals) cb 17

Diameters of Ds mils ness. cnemenecaioneseee anteroposterior. ....-...... 28
CLAMSVELSO circtecismushaalatiets me 19

These teeth resemble very much in their details the temporary molars
on which Leidy proposed his Merychippus insignis, but are much more
elongate anteroposteriorly, agreeing in their measurements with the M.
mirabilis, of which the temporary molars iii and iv are also figured by
Leidy. ‘The latter appear to present a later stage of wear, and therefore —
a greater transverse diameter.

PROTOHIPPUS PLACIDUS, Leidy.

Plate XI, Figures 3-8. For synonymy see above.

Teeth from eight different localities in Donley county represent proba-
bly ten individuals of this species. The characters of the superior molars
differ much with age and wear, as already remarked. Younger animals
with less worn teeth represent the Hippotherium gratum of Leidy. In the
early stage of wear not only is the protocone distinct from the paraconule,
but the adjacent enamel borders of the lakes are rather complex. ‘Thus
there are, besides the loop on the posterior internal border of the anterior
lake, three folds of the opposed enamel lake border, but also sometimes
an emargination of the posterior border of the posterior lake. The num-
ber of emarginations diminishes with wear, until in old teeth all, except-
ing perhaps the loop, disappear.

I give the following list of teeth, with their length and the complexity
of enamel which they present:

I. Hippotheroid.
PP Length Mm.

Inflections, 3 anterior, 2 poOsterion. .\.. >. ses sie ses cies ieipeleleteleleiste = + ==!) 36
Inflections, 2 anterior, 2 posterior............,.20:eeereeeteer pester eeseees 40

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 35:
Inflections, 3 anterior, 1 POsteTiOT“.......... ec eee eee eee eee eee neces 31
Inflections, 3 anterior, 1 POSsteViOL“......... ccc eee ee eee ete eee tte tenes 40
Inflections, 2 anterior, 1 posterior.............. cece cece ee eee et tee eee 36
Inflections, 1 anterior, 0 POSteTiO“.......... 2. cece eee eee ee eee ree teens 42

II. Protohippoid.

Inflections, 3 anterior, 3 posterior........... cece cee eee teenie ees 24
Inflections, 1 anterior, 2 posterior... .......6csceee ecw cence wenn c ec enacces 28
lorflections, I amtervor, O)POStETION.. jn csec ccc sncicce chen e wesc canveenss sees 26.

In all these specimens the posterior loop of the anterior lake is present,
and it is this circumstance that induces me to think that there may be an-
other small Protohippus, which is a distinct species, in which this loop is
always absent, and to which the name of P. parvulus is applicable. As
has been already remarked, superior molars of three individuals of this
character were obtained at the same locality as that from which the speci-
mens of Protohippus placidus were found. These are all old individuals
with well-worn molars, the length of the crownsin two of them being 24
mm. and 21 mm. respectively. Younger teeth of this kind I did not
find. Considerable light is, however, thrown on this question by some
teeth from Nebraska, obtained for me by Mr. Frank Hazard. They ap-
pear to be M. i and M. iii of one side, and M. iii of the opposite side of
the same individual. In M. i the structure is fully protohippoid, and
there is neither loop nor inflection; length 25 mm. In M. iii of the same
side, the protocone is barely fused, there is rudimental loop and there are
shallow plications 2-2; length 24 mm. In M. iii of the opposite side,
the arrangement is hippotheroid; there is a rudimental loop, and 2-1
weak plications; length 25 mm. In two superior molars obtained by
myself in northeast Colorado the protocone is connected with the paraco-
nule by a narrow isthmus. There is a mere trace of the loop, and the
enamel borders are undulate, but not plicate. Crowns 16 and 14 mm.

It is thus evident that it is impossible to separate the P. parvulus from
the P. placidus by characters of the superior molars.

A mandible lacking half the left ramus and the coronoid and angular
portions of the right, is probably referable to this species. The right,
series Of molars, with the crowns of three incisors, and alveoli of the
others and of both canines are preserved. The teeth are well worn, but.
traces of the cusps of the incisors remain. The canine is separated by
a short diastema from the third incisor. The third premolar is rather
short. The third true molar is on the contrary elongate, and has a large
heel, in great contrast to the P. pachyops. The molars are much worn,
but it is evident that both lobes of the metaconid are tolerably well de-
veloped, and that the hypoconid is larger than the paraconid. The
mental foramen is below the middle of the diastema. No trace of a
fourth premolar. The last molar is elevated posteriorly on the sloping
base of the ramus.

36 GEOLOGICAL SURVEY OF TEXAS.

Measurements of Mandible.

Mm
Length from heel of last molar to incisive alveolus.....................00% 143
Length from heel of last molar to symphysis........................-0000 111
Length from heel of last molar to canine................... cc cece veces eee 123
Length of molar Seriesiie.:..ic/ctise.cieicinsicieres 9 ste) sciclisicrsisie Sela ana eee 84
Length of true: molars’ 2s). csi ns oie wie wnle eels si ciaiclepersie.c aie ee Gea eee 43
Leng thiof third premolar, |<. cije--cier\stisvestays env si sycovis. siete tere eile one 14
Width /of third premolar. 3 2c) sawn s cere ates wera sia nate Saree caer cee nee 9
Length ot firshirue molarien sneer cne cach eet eck eee teen 13
Width ofimrstytrue molar Gas enaee cies atten shieieemiacisen ate Sera eRe 10
Len athvof last true mol arian. ss.exi pee acide wiceo cialis ame aia Oar 19
Widthyof last truesmolar cies ciynscbieide cl Recon rma eiabiok eraaie caret 8

HIPPOTHERIUM, Kaup.

Cope, Proceeds. Amer. Philosop. Society, 1889, p. 429.

Hipparion, Christol. ?Merychippus and Anchippus, Leidy.

Species of this genus are much less abundant in the Loup Fork beds of
Donley county than those of Protohippus, and these belong to the larger
forms.

HIPPOTHERIUM AFFINE, Leidy.

Extinct Mamm. Dakota-Nebraska, 1869, p. 286, pl. XVIII, figs. 20-24.
Hippotherium occidentale, Cope, Proceeds. Amer. Philos. Society, 1889,
pl. I, fig. 1 (not of Leidy).

A single superior molar found.

HIPPOTHERIUM OCCIDENTALE, Leidy.

Proceeds. Acad. Phila., 1858, p. 27. Hipparion occidentale, Leidy, op.
cit., 1856, p. 59; Extinct Mamm. Dakota-Nebraska, pp. 281, 326, pl.
XVIII, figs. 1-5; pl. X XVI, fig. 2.

A fragment of a maxillary bone with four molars, and some bones of
the skeleton of one individual; and a single superior molar of a second
individual. These present the superior degree of complexity at an age
at which the enamel plates are comparatively simple in the H. affine, as
pointed out by Leidy.

PROCAMELUS, Leidy.

J have before me jaws of five species of this genus, and the examina-
tion of these, with previous examinations of other specimens, leads me to
define the former as follows:

I. Mandibular ramus at M. ii, about three times as deep as the eleva-
tion of the crown of M. ii, above alveolar border.

a. Premolar series short, equal two columns of last inferior molar.

“VERTEBRATE FAUNA OF THE LOUP FORK BEDS. ot

Inferior premolars 36 mm.; last inferior molar 43

UREPORT, SE Tal fiat a plaidic se eye die wale aval ola waiens P. angustidens, Cope.*
aa. Premolar series equaling or exceeding last inferior premolar in
length.
Inferior premolars 47 mm.; M. 5,47 mm..........- P. robustus, Leidy.
Inferior premolars 41 mm.; M. z, 38.5 mm..... P. occidentalis, Leidy.t
Inferior premolars 31 mm.; M. 3, 33 mm........... P. gracilis, Leidy.{

II. Mandibular ramus slender; at M. ,, 1.5 times elevation of crown
of M. 5.
Length of M. 5, 28.5 mm........ 5 CREM oe P. leptognathus, Cope.

PROCAMELUS ROBUSTUS, Leidy.

Extinct Mamm. Dakota-Nebraska, p. 148, pl. XV, figs. 1-4.
Very abundant, but well preserved jaws and teeth are rare.

PROCAMELUS GRACILIS, Leidy.

Op. cit., p. 155, pl. XIV, fig. 15.
Represented by the almost complete dentition of the lower jaw of one
side. Bones of the skeleton not uncommon.

PROCAMELUS LEPTOGNATHUS, Cope.

Sp. nov.

This camel is represented by a skull which includes the cranium with
lower jaw as far anteriorly to and including the last two true molars. The
considerable part of the skeleton of a camel of appropriate size was found
near to the skull. At present, I content myself with describing the lat-
ter. It was inclosed in a calcareo-siliceous concretion, from which it was
cut with some difficulty. The lack of the premolar teeth renders its
reference to the genus Procamelus uncertain; but it is nevertheless prob-
able that such reference is correct.

The cranium is somewhat distorted by pressure, as it lay on its side,
so that it is probable that the postoptic region has been somewhat ex-
tended beyond its normal length. This will not, however, account for
the elongation of this region as compared with the crania of P. angusti-
dens and P. gracilis (P. occidentalis, Cope olim), with which I have com-

* Bulletin U. 8. Geological Survey Territories, I, 1874, p. 20.

+?Procamelus fissidens, Cope, Report U.S. G.G. Surveys W. of 100th Mer-
idian, 1V, Vertebrata, p. 327. In the drawing of the grinding face of the mo-
Jars in Leidy’s Extinct Mamm. Dakota-Nebraska the last lower molar is too
short by the measurements and by the profile view given in the same work.

{Measurements taken from Texan specimen. Procamelus occidentalis, ‘‘Leidy,”’

Cope, Reports U.S. G. G. Surveys W. 100th Meridian, IV, p. 329, pl. LIII,
LXXVI, LXXVIII, LXXIX; P. gracilis, 1. c¢., p. 328.

38 GEOLOGICAL SURVEY OF TEXAS.

pared it. The vertical diameter of the orbit enters the postorbital length
3.5 times. In the P. gracilis it enters 2.5 times, and in the P. angusti-
dens twice. The frontal width enters the same 1.25 times. In P. gracilis
it enters .75 times, and in P. angustidens .66 times. The parietal profile
is decurved posteriorly, as in P. gracilis, and the inion is a prominent
convex crest. The sagital crest is elongate in correspondence with the
elongate parietal region. ‘There is no evidence of the deep superciliary
notch which is so striking in the two species of the genus above named.
The paroccipital and postglenoid processes are elongate, the former a little
the shorter, and fused with it for more than half the length of the latter.
The latter dimension from the auricular meatus equals the vertical diam-
eter of the orbit, as in P. gracilis. The maxillary bone projects posterior
to the last molar 10 mm., or opposite to the anterior border of the pos-
terior nares. The lateral palatine notches extend 13 mm. anterior to the
posterior extremity of the maxillary bone.

The mandibular ramus is remarkable for its slender proportions. Its
posterior border has a well defined offset near the extremity of the post-
glenoid process when in place. The coronoid process is greatly elevated,
reaching when in place to a point above the frontal plane.

The crowns of the second and third true molars in both jaws (the only
ones preserved), are compressed. Vertical ridges are little marked on
the internal side of the crowns of the inferior molars. The third lobe of
the last inferior molar is narrow, and only half as long anteroposteriorly
as each of the other columns.

Measurements.

Mm.
JOCNOIAN Ot PVR INIMs, S45 sens Qhondadao pense aDOdaos dat aon Ha DOSeODaAOOROLS 200
Length from anterior border of zygomatic foramen to inion (axial)...... 128
Length from foramen magnum to palatal border................0++ eee 98
Interorbital width... 2.2. .5-.-.- Pee UaRere eri a teawtete eer nce lege loners Reh nese veiw aasrs Tote 140
Width at auricular meatus (Compressed?) crc e- te ceiye cree ele i ei wae cel 58
Wadthiottocerpital Weomdiylesmerr ne reg icin tee trtalelel ere ca tetal ela fic so aera aefet= 45
Width of palateabtnomt of lastimolanssm-memesee: se -iit- sein eee eee 27
Width ofiposteriormanesseariemieie corre aeeiecieieers ociae pro sstciie ee ete 12.5
Mlevation of Loweryjawiaib CONOWONG sneyeyie tae jefe) stele t~ ele cis (= aie *)cle'el jet eee 142
Hlevations OLelowyer a ayiacewe uli verter eeels iovs cela) (cues <\ais)ojie\0 ea alaks aisle (acter ete eneee 23
Width of lower jaw aticondylen rmjysrcrtejeteo = sicieye- cle um «/-ereiei che ee 43
Width of slower jaw ab; ame leprae iee sate l=icsse 2011s = sivicledoigieyehetie seat ee5 (Off
é ; os anteroposterior ......... 24
Diametersisuperlocel wiser ease tee... oe | transverse ak Pace 18
f s ad anteroposterior......... 25
Diameters SuUperlor Wl aii meee ee ole soles cle 6 | transverse ahinatC eS
: . ae anteroposterior ......... 23
Diametersumferor ME ier inelemie sie es sce cles | trAneVeree Gee 12
R ya anteroposterior ......... 30
Diameters inferior Mey cave mcile-ieicre e's opie’ | FO SB ey) toh ee 14

~

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 39

As already indicated, this species is of about the dimensions of the P.
gracilis so far as preserved, but differs widely from this and from other
species in the slender form of the mandibular rami. The vertical diame-
ter of the latter is about half of that characteristic of the P. gracilis.
The postorbital region is also more elongate.

BLASTOMERYX, Cope.

Report U. 8S. G. G. Surveys west of 100th meridian, IV, 1877, p. 350;
American Naturalist, 1889, p. 125.

BLASTOMERYX GEMMIPFER, Cope.

Op. cit., p. 360, pl. LX XXII, fig. 13 (Dicrocerus). Merycodusgem-
mifer, Cope, Ann. Report U. S. Geol. Survey of Terrs., 1873 (1874),
p. 531 partim.

Parts of two individuals represent this species. The most important
specimens include the posterior four molars of the right side, the P. m. i.
and M. i fixed in a portion of the maxillary bone, and a part of the
right ramus mandibuli with the posterior four molars in place. The sec-
ond individual is a little larger than the first, and includes the left infe-
rior M.i and a part of the left inferior M.iii. All these teeth were
found by myself, lying close together.

As the characters of this species are little known, I give an account of
these teeth. The molars are all moderately brachydont, with the basal
shoulders visible on the alveolar border. The superior molars are with-
out styloid tubercles between the bases of the internal columns, while
they are present in all the inferior true molars. In this respect the supe-
rior molars differ from those of the larger B. borealis, Cope, where the
stylets are present. The crowns of the superior molars contract rapidly
transversely to the apex. The anterior and posterior bounding vertical
ridges of the metacone are prominent and there is no median crest.. The
paracone presents a strong anterior bounding ridge and a strong median
ridge; all asin the B. borealis. No cingulum. The first premolar is small,
and its external border marks the anterior lake of the first true molar.
The external face is concave on the anterior half. The part of the exte-
rior wall anterior to this concavity is protocone, and it sends a process
inward towards the internal crescent.’ Posterior to this process, the ex-
terior wall is apparently tritocone,* and it is convex on the inner side.
The internal crescent or deuterocone is regular; and extends transversely
in front anterior to the protocone, from which it is separated by a notch.
Above (below) this notch the protocone presents an external ridge; prox-

‘imad there is no ridge. No cingula.

*See Scotton Nomenclature of Premolar Cusps, in American Journal of Morph-
ology, 1891, p. 49.

40 GEOLOGICAL SURVEY OF TEXAS.

The first (posterior) premolar presents a crown constructed—first, of a
posterior column with a crescentic section, the convexity forward; sec-
ond, of a column with crescentic section, with the convexity backwards
and outwards; and third, of a cusp which is compressed so as to be an-
teroposterior. These cusps are deeply separated on the inner side of the
crown, but fused on the external side. In the true molars the tritocone
and tetartocone are separated at the postero-external angle of the crown
by a deep notch. The stylets diminish in size from the first to the third
molar, and there is none between the second and third columns of the
third molar. On the external side of the protocone in the true molars is
a deep vertical groove, which is bounded in front by afold. No cingula.
Internal faces of columns gently convex in transverse section.

Measurements.

Mm

length of superior true molar senies- a5. ae eee eee eer 30

Diameters of base of M.i.................... aLETO ROR EL Oa aear 10

tLANSVELSe.. cino1--eeele eee 10

Diameters:of Malic eect ee ee ee anteroposterior...) ..-24) a

Lrans Verse ys0..2 cee 11

Diamoetersrol Pmt hs ss ceele. oe eee eee anteroposterior ........»- 6

transverse: i-pi kisses 6

ALenothiotseries of infer1on true mOlars) 1.12 cmc cele tele ene meee ante 30
Disimerers Mea anteroposterior .......... 9.5
ED OO Une. miei ian alae eo LransVerse-eceneeeReeee eee

2 ies anteroposterior .......... 13
Diameters pM caiiie ey accsyayarsraraleresotarercuclertelelalers ciclevete | Leaneyerne eee 5.8

There remains a doubt as to whether this specimen belongs to the B.
gemmifer. The last inferior molar agrees closely with the one referred to
that species by me in the Vertebrate Paleontology of New Mexico, in
Volume V of the Report of the United States Geological and Geographic
Survey West of the 100th Meridian; but this is a slender basis of identi-
fication. The typical specimens, which are from the Loup Fork beds of
Colorado, I can not at the present find, but hope to do so before my final
report to the Geological Survey of Texas is published.

APPENDIX TO THE REPORT ON THE LOUP FORK TERRANE.

A small collection made by Mr. Cummins near Goodnight’s, on the
Staked Plain, presents characters which distinguish it from the faune of
the Loup Fork and Blanco formations. According to Mr. Cummins, the
Loup Fork formation is overlaid by a bed of gravel, which passes under
the fossiliferous formation at Goodnight. He consequently regards the
latter as of later age than the Loup Fork, while he thinks it older than
the Equus beds of Rock creek. The paleontology sustains this view,

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 41

The fossils include metapodial and the tarsal bones of a rhinoceros pre-
. sumably of the genus Aphelops; fragments of a superior and inferior
molars of a true horse (Equus); and superior molars of horses probably
of the genera Hippidium and Protohippus. Neither the first nor last
named of these genera has been found in the Blanco, while they do occur
in the Loup Fork. The genus Equus, however, is not known in the lat-
ter formation, but first appears in the Blanco. The fragment preserved
is quite characteristic, and I see no way at present of distinguishing it
from the Equus simplicidens, Cope, of the Blanco bed, but better speci-
mens may indicate another identification. The species which I can iden-
tify are the following:

PROTOHIPPUS LENTICULARIS, Cope.

Sp. nov. Plate XII, Figures 1, 2.

Two superior molar teeth represent this horse in the collection from
Goodnight’s. They indicate a species of the size of the Hippotherium
speciosum, and present several peculiarities. The most conspicuous is
seen in the form of the protocone, which is long separate from the para-
conule. It has an absolutely lenticular section, presenting acute angles
anteriorly and posteriorly, and convex surface internally and externally.
In this respect it differs from all the species of Hippotherium and Proto-
hippus known to me. The column is fused towards the base with the
paraconule, so that an old animal belongs to the genus Protohippus, as in
the case with the Protohippus placidus, described on a preceding page.
As both the teeth of P. lenticularis are only partially worn, the pattern of
their grinding faces is that of the genus Hippotherium.

The enamel borders of the lakes are moderately complex, the anterior
having the posterior loop nearly isolated, and a trace only of other irreg-
ularities, while there are two deep notches of adjacent borders of the pos-
terior lake. The remote borders of the lakes have each a mere trace of a
notch. There is one deep loop of the internal border, which extends to
the protocone in one tooth and nearly to it in the other. It is rarely so
pronounced in the three-toed horses, and when large is frequently double.

The crown is curved transversely but not anteroposteriorly.

Measurements.

Mm.
longitudinal .............. 48

Diameters crown No.1...................... transverse ............c!.: 19
anteroposterior ........... 21

Diameters crown No. 2.................0005. AU OEM ET GRE ES rane = ae
: EEAMISVIETSCN. = leva lege ciaccis costs es 18

The long separation of the protocone and paraconule allies this species
to the P. placidus, Leidy, but from the latter it is well distinguished by
its superior size and by the shape of the protocone. The Hippotherium

42 GEOLOGICAL SURVEY OF TEXAS.

relictum, Cope, from the Pliocene of Oregon, is of approximately the
same geologic age, but this is a true Hippotherium, and the column (pro-
tocone) has an oval section.

Another species of Protohippus was found by Mr. Cummins at the same
locality. As it is represented by only an uncharacteristic superior molar,
I do not attempt its identification.

PROTOHIPPUS PERDITUS, Leidy.

A single right superior molar, moderately worn, presents no tangible
differences when compared with corresponding teeth of P. perditus from
the Loup Fork beds of Colorado. I nevertheless refer the animal to this
species provisionally, as I can not prove that it is not a species of Hip-
pidium.

HIPPIDIUM INTERPOLATUM, Cope.

Sp. nov. Plate XII, Figures 3, 4.

Established on two right superior molars, probably derived from the
same animal. They are apparently the first and second true molars. The
form and area of the grinding surfaces are similar to those of the cor-
responding molars of the domesticated horse (Hquus caballus). They
may be distinguished from the corresponding teeth of the species of Pro-
tohippus by the small size of the protocone and hypocone. ‘The former
reached posteriorly to the line of the anterior border of the posterior
lake, but does not overlap it, as is the case with the species of three-toed
horses generally. Its junction with the paraconule is strongly constricted.
The internal enamel border between the protocone and hypocone is in-
flected to a point beyond the line of the internal border of the interior
lake, and in front of its apex it sends inward a deep narrow loop. The
lakes are relatively large, and the borders are quite simple. The anterior
border of the anterior lake is simple; the posterior border has an inflec-
tion but no loop. The exterior border of the posterior lake has one in-
flection, and its posterior border a slight emargination. Owing to the
transverse width of the lakes, their bones are little produced. The
crowns are curved transversely, but scarcely anteroposteriorly. Ce-
mentum abundant. Roots very short.

Measurement.

Mm
Diameters of grinding face of M.i........... anteroposterior.........- 28
ELANISV CTSE Gifemictrecineteies 27
Diameters grinding face of M.ii............. anteroposterior..........- 29
TLANSVEUSC Giltleleniels eee = OSD
Mene thro heroin Of Me tie. ayy ote te nielatalale) =) leletetnisy tater s) aie tate tetet sie tete fete betel Ts) = 6d

The crowns are sufficiently worn to present the character of maturity.

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 43

We learn then, that the emargination of the enamel borders of the lakes
are not characters of immaturity. As compared with the Pampeian
species,* the enamel borders of the H. interpolatum are more simple;
while they are not so simple as in the species from Oregon which I have
called H. spectans.t| In the latter the posterior lake borders are not
emarginate, and their external borders are more deeply concave. The
lakes are wider, a character which may be due to wear; but a further
difference is the greater posterior production of the protocone, which
considerably overlaps the line of the anterior border of the posterior lake.
The ZH. interpolatum is of about the size of the H. spectans and H. neogeum.

HIPPIDIUM PSPECTANS, Cope.

American Naturalist, 1887, fig. 41. Huj. op. Plate XII, Figures 5, 6.

Two superior molars belong to a species allied to if not identical with
the one above named. One of these is considerably worn, while the
other, the posterior of the left side, is little worn. Both display charac-
ters different from those of the H. interpolatum, as follows: The proto-
cone is large, and its posterior border is opposite the middle of the pos-
terior lake. The enamel borders of the lake are simple, a slight notch in
one lake of the younger tooth excepted. The size is smaller. The di-
mensions are about equal to those of the Protohippus supremus of Leidy,
but in that species the anterior lake has a large loop, and the lake borders
are elsewhere folded. It agrees with the H. spectans, especially in the
simplicity of the lake borders, which the young molar shows is not a
character of age, as in most other species of horses. The hypocone is not
conspicuous in either of the teeth. Both exhibit transverse curvature,
and the last molar a little anteroposterior curvature.

Measurements.
- Mm
Diameters of older molar.................... | AMEE EOD OSCMON Ie 5 ze
TANS VETSOM 2-3. cue tee 27
longitudinal .............. 64
Diameters of last molar..................... anteroposterior ........... 24
HTANSVEUSChsesccsalelavercjelewys ova 20

EQUUS EURYSTYLUS, Cope.

Plate XII, Figures 7, 8; Plate XX, Figure 6.

This small but remarkable true horse was first brought to my notice by
a broken inferior molar from the Paloduro canyon, where it was found
by Mr. Cummins. The horizon of this locality was unknown to me, but

* Burmeister, Los Caballos Fossiles dela Pampa Argentina, Buenos Ayres,
1875.

+ American Naturalist, 1887, p. 1072.

44 GEOLOGICAL SURVEY OF TEXAS.

the discovery of four additional lower molars at Goodnight’s by Mr.
Cummins fixesit. It is the most characteristic species of the epoch which
intervened between the Loup Fork and Blanco.

The species belongs with the #. minutus, Cope, to a section of the genus
characterized by the relatively great width of the metaconid-metastylid
column of the inferior molars, and its close appression to the protoconid
and hypoconid, and hence by the relatively narrow molar crown; and also
by the small size. ‘The present species is superior in dimensions to the
E. minutus, and differs from it materially in the small size of the hypo-
stylid. From this it follows that the broad flat posterior channel of the
internal side of the crown, which characterizes the H. minutus, is absent
from this species, and a narrow channel with rounded base, rising to the
metastylid side, takes its place. The terminal fourth of the crown has a
considerable cementum investment, but the remainder of the crown is
nearly naked, as in #. minutus. ‘The hypostylid is separated from the
metastylid by a sharp groove in the H. simplicidens; and this rib and the
metaconid are more prominent in that species. In this species and in the
EH. minutus, as in some of the teeth of the horse and the quagga, the deep
enamel inflection of the external wall enters the metaconid-metastylid
isthmus. In the single molar of #. ewrystylus this is not the case. The
anterior and posterior faces of the crown are flat in both the H. ewrystylus
and the H. minutus, and the crowas of the teeth observed are gently
curved anteroposteriorly.

Anteroposterior diameter of crown at middle, 20 mm.; ditto of meta-
conid-metastylid, 13 mm.; transverse width of crown restored, 11 mm.
Corresponding measurements of E. simplicidens, 30 mm., 18 mm., and 18
mm. respectively.

Other specimens examined since the above description was written
throw much additional light on its characters. These are four inferior
molars, all from Goodnight’s, and all apparently from as many individ-
uals. From these it seems that the external faces of the protoconid and
hypoconid are flat and not convex as is usual in this genus. Also that
the hypoconid throws outwards an acuminate or acute loop just before
joining the protoconid, which loop is the summit of an acute ridge of the
middle of the external face of the crown. Next, the hypostylid is much
more extended anteroposteriorly than is represented in Plate XX, fig. 6,
where it is indeed rather smaller than in the tooth from which it was
drawn, owing to the latter being fractured at that point (see fig. 6a).
It is not flat on the inner face as in H. minutus, but is convex, and has a
posterior recurved crest, which forms a posterior marginal ridge of the
crown. This ridge is not equidistant from the metastylid in the different
specimens. It is nearest the latter in the tooth first described (No. 1)
and figured, as above cited. In another specimen (No. 5) it is not

VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 45

further off, but is strongly recurved, forming a prominent narrow ridge
bounding the inner side of the crown posteriorly. In the three other
specimens (2, 3, 4) it is not prominent, and is separated from the meta-
stylid by a rather flat gutter, as in HZ. minutus. Three of the crowns, in-
cluding the type, are curved anteroposteriorly; the one with the strong
bounding ridge is straight. None are curved transversely. All are
wider anteroposteriorly at the grinding face than at the root, a differ-
ence most observed on the least worn crown. Cementum is present on
the internal face near the grinding surface only; on the external face a
thin layer extends nearly to the base. The anterior and posterior faces
are naked.

Measurements.

Mm.

longitudinal .....,..... ... 55

WTAE FETS INO.) «:s)arc aco «: vreie e1a'o. wiele oie-e a/cve.dewie ele anteroposterior ............ 24.
LENOVO) GSoodaaneneonnasd 10

longitudinal............... 40

Wiameers) NOs Om s -itick eases Gleic Cneiacmterta anteroposterior ............ 22
EVAMISVELSE ei epsisiciaieie ele eserves 12

As compared with this species the H. minutus differs as follows: (1) In
the convex protoconid and hypoconid; (2) in the absence of external
median keel (loop); (3) in the absence of an anterior marginal bounding
ridge of the external side of the crown; (4) in the inferior size. The Z.
minutus is undoubtedly from the Blanco bed, and may be the direct
descendant of the H. eurystylus.

SYNOPSIS OF SPECIES.

Mr. Cummins found in the bed above the gravel which overlies the
Loup Fork formation, the following species:

Aphelops, sp.

Protohippus lenticularis, Cope.

Protohippus, sp. No. 2.

Protohippus ?perditus, Leidy.

Hippidium interpolatum, Cope.

Hippidium ?spectans, Cope.

Equus eurystylus, Cope.

Equus ?simplicidens, Cope.

As already remarked, the genera Aphelops and Protohippus are char-
acteristic of the Loup Fork beds, but are not known to extend higher.
Equus, on the contrary, has never been found in the Loup Fork forma-
tion, but is the only genus of horses found in the Blanco and Equus ter-
ranes. Hippidium is said to be derived from the Loup Fork beds of
Kansas and Nebraska, but I have never found it in place. It is likely

Three of the others are not distinguisha’ le fi

Blanco terranes.

to occur in higher beds, from its more quin

come to species, the three which ar

known species. One of these is Loup Fork, on
(Hippidium spectans) is of uncertain horizon. |
in question represents an age intermediate between th ‘

Cla? Ein Th,

THE VERTEBRATE FAUNA OF THE BLANCO BEDS.

A report on collections made in these beds by Mr. W. F. Cummins
was made by me and published in the Third Annual Report of the Geo-
logical Survey of Texas, 1891, p. 251. During the past season I accom-
panied Mr. Cummins in a more thorough exploration of this formation,
near the eastern border of the Staked Plain, and we added materially
to the knowledge of its vertebrate fauna. The results will be found in
the following pages. The inference as to the position of the Blanco ter-
ranes in the Cenozoic series which I formerly announced, are confirmed;
viz., that its position is between the Loup Fork and Equus terranes. The
fauna is intermediate and peculiar, as not a single species occurs in it
which has been found in the terranes prior or subsequent to it in time.
The horizon is more nearly and strictly Pliocene than any of the lacus-
trine terranes hitherto found in the interior of this continent.

THSTUDINATA.
TESTUDO, Linn.
THSTUDO TURGIDA, Cope.

Proceedings Amer. Philosoph. Society, 1892, p. 127; Ann. Report
Geol. Surv. Texas, 1891, p. 255 (published 1892).

Seven specimens of this species were found together at one locality,
which did not yield any other vertebrate remains. Fragments of two
other individuals were found at other localities in direct association with
Mammalia.

TESTUDO PERTENUIS, Cope.

Proceedings Academy Nat. Sciences, Philadelphia, 1892, p. 226.

Founded on a large specimen measuring three and a half feet in length
by three in width, and remarkable for the transverse width of the vertebral
dermal scuta. The carapace is rather flat and descends steeply posteriorly,
the anal marginal bone being somewhat incurved. Margins of carapace
flare outwards above the legs. The plastron has a rather wide lip, with
flat: base and straight lateral borders; its anterior border is lost. The
posterior lobe is deeply and widely notched, terminating on each side in
a subequilateral angular prominence. Both carapace and plastron are
without sculpture, the posterior angles of the plastron only being longi-

48 GEOLOGICAL SURVEY OF TEXAS.

tudinally grooved below. The vertebral scuta are considerably wider
than long, as is also the anal scutum. Both carapace and plastron are
very thin, not exceeding one-quarter inch in the specimen described, ex-
cept at the borders.

Measurements.
Length over allisnvccccicvc alee das 1s seinen sereine «cle cies (fetene terete taeeas 4.2 feet
Width Overall oyeieicteteejsiciarc is ds ts b.claisivelelsrelevels, bisis aiele oer teh Re roe eee 4 feet
Width of penultimate dorsal scute..............00. cece cece eenecers 1.275 feet
Fern biog veianetel ferereterotetale lesen (sloje eratoneterelopatersieicr Tuebeietalars iio) ere)= eects np eet eee 85 feet
Widthoflast wertebral’scuite sc ic/c esse ese cdscsrs yew oiesejaloisisiercie aie sve enclewlete eins 1.35 feet
WY LGC OR AMA ISCULE jaiccc trate ls erste oisvevelcrerere eleven ctoraneleleiorntasieac/ Miers losaisah veneee isle 1.5 feet
ILMB DAU, Bos ongHed Hon bem Ooosod aobEHaadoDonabUNeCK Se ac6 omen. ga oBeoCOe 6 feet
Length of penultimate costal scute............. cece ce eee eee ener ees 9 feet
Henipthiof last costal ste) ciscs:< sie aval ausokevs cheval eveserevg okettesl ole le Mbeane eave onncneiets -95 feet
Width of lip of plastron at base...... 0.6.0.0... eee eee eee eee ence 8 feet
Wiadth of anterior lobelatiaxillaes i. . ar ipecicis aislereientete =melledenieeieieneralte 2 feet
Width of posterior lobe of plastron at base.................220.eeee 2 feet
Width at fundus of median notch. ...........-.. ee eee cere ee eens 11 feet
Width at apices of angular processes.................eeeeeeeseeeeee 85 feet
Dep thio) WO bel eof hinyesisl <deveiale carve cieye.e cieds behav ouetane ae elec ieee ahs eat 5 feet

This is the largest species of land tortoise yet known from North
America.

=
ae

-

VERTEBRATE FAUNA OF THE BLANCO BEDS. 49

Fig.1. Testudo pertenuis, Cope, one-fourteenth natural size.
1. Portion of carapace from above.
2. Posterior lobe of plastron from above.

EDENTATA.
MEGALONYX, Jeff.

MEGALONYX LEPTOSTOMUS, Cope.

Sp. nov. Plate III, Figures 1-3.

This species is represented by a number of fragments of the skull and
a superior molar tooth, probably the last of theseries. ‘The most instruc-
tive fragments are the palatal portions of both premaxillaries, with the
alveoli of the canine-molars; and portions of the palatal portions of the
maxillaries, with parts of alveoli of several molars. The right occipital
condyle is also preserved.

The only species in which the corresponding Eade of the cranium
are known are the Megalonyx jeffersonii, Harl., and the WM. leidyt, Lindahl,
but the teeth of the other species may be compared with those of the

4—Geol

.

50 GEOLOGICAL SURVEY OF TEXAS.

present one, especially the canine-molars, of which a good idea may be
gained in the M. leptostomus, from the form of its alveolus.

The palatal portion of the premaxillary bones is bifurcate from an acute
angle posteriorly, which is opposite the posterior border of the alveolus
of the canine molar. Neither moiety extends anterior to the anterior
border of that alveolus. The alveolar ridges approach posterior to these
alveoli so as to be separated by an interspace equal to two-thirds that
which separates the alveoli. In MM. jeffersonii and M. leidyi this width is
equal to that which separates the canine-molars; and the premaxillary
palatal emargination is rounded, broadly so in the M. leidyi. The M.
leptostomus is remarkable for the narrowness of the palate throughout, the
width equaling about two-thirds that of the corresponding region in the
two species mentioned. It is in consequence narrower than the transverse
diameter of the molars, while it equals that diameter in the two species
already described.

The form of the canine-molar is different from that characterizing the
other known species of the genus. The alveoli, instead of having con-
cave internal borders, divergent from each other outward and backward,
as in M. jeffersonii and M. leidyi, have their internal borders parallel and
directly anteroposterior. They present posteriorly a wide border at right
angles to the internal border, and passing into the latter by a rounded

angle. The form of the tooth is therefore more or less triangular, or

similar to that of a molar tooth placed longitudinally. This is a suspi-
cion only, as the external and anterior alveolus walls are unknown. The
form of the known part of the alveolus, however, shows that the canine
molar is not only very different from that seen in the two species men-
tioned, but is equally distinct from those of the M. loxodon, M. wheatleyi
and WM. tortulus, Cope, and the M. dissimilis of Leidy. Neither the in-
ternal nor the posterior alveolar borders display any grooves or concavi-
ties, but are perfectly plane.

The alveoli of the molar teeth indicate that they differ in the antero-
posterior diameters of their widest or internal extremity. The supposed
last molar is about equal in dimensions to the middle molars of the .
jeffersonii and M. leidyi, and is one-fourth larger than those of M. wheat-
leyi and M. dissimilis. Its diameters are uniform from base to crown.
Its horizontal section is a narrow triangle with rounded angles. Its an-
teroposterior diameter is smaller in relation to its transverse than in any
species known to me. The forms of the inner borders of the alveoli indi-
cate that some of the other molars are relatively wider in the fore and aft
direction.

————

Fea

VERTEBRATE FAUNA OF THE BLANCO BEDS. 51
Measurements.

Mm

Depth of premaxillary notch (axial) .........cee cece cee eet e eee e ens 33

Width between canine-molar alveOli ..... 1... ccc cece eee eee eee eee eee 43

Width of inferior face of premaxillaries............. cece ee cen cee cree eeces 35

Width posterior to canine molars........... 0. cece c cece ete cece 27

Width of premaxillaries at posterior external angle of canine-molar alveolus 83

Width of palate between molars... .......0.. cece eee cece cee ceseeseans 18

Transverse diameter of occipital condyle............. cece eee ee eects 28

Diameters canine-molar alveolus............. | anteroposterior ........... 25

EVANISVCTSEleciect- siete ose ccleie 18

Anteroposterior width inner face of alveolus of middle molar...... ....... 15

longitudinal.............. 61

Diameters of (?) last molar.................. anteroposterior (greatest). 14

EAN SVECVSC!. c.)s ccc «soils sie 25

The specimen above described was found by Mr. W. F. Cummins.
The discovery is of much interest, as carrying back our knowledge of
the presence of this genus of sloths in North America to an older terrane
than that (the Megalonyx beds) in which it has been hitherto known to
occur.

CARNIVORA.

Three species of this order were found, a number about in proportion
to those of other orders. ‘Their remains are in rather a poor state of
preservation, as the conditions of deposit appear to have been unfavora-
ble to the integrity of any but large and strong bones and teeth. Three
families are represented, viz.: Mustelidsz, Hyzenide and Felide. The
discovery of Hyznide is a noteworthy circumstance, and adds materially
to the Old World facies of this part of the fauna. The absence of the
Canide, usually by far the most numerous family of Carnivora, is curious,
and is probably accidental.

. CANIMARTES, Cope.

American Naturalist, 1892, p. 1029.

True molars 3; second inferior molar with one root; ‘meorior secto-
rial with well developed blade, trenchant heel, and large metaconid.
Superior sectorial with small protocone anterior in position, and without
distinct anterior basal lobe.

As in the typical genera of the family, the first superior tubercular
molar has an expanded obtuse internal cingulum. As compared with the
genus Mustela, to which it approaches, Canimartes differs in the posses-
sion of the superior M. ii. Its dental formula is the same as those of
Stenoplesictis Filh. and Amphictis Pom.; but it differs from both in im-
portant details. Thus the heel of the sectorial is cupped, and the inferior
tubercular is elongate and quinquetubercular in the former; and in the

52 GEOLOGICAL SURVEY OF TEXAS.

latter the superior tuberculars have no internal cingulum, and the first
inferior tubercular is like that of Stenoplesictis.

In the two superior true molars we have the persistence of an ancient
character in this family.

CANIMARTES CUMMINSII, Cope.

Sp. nov. Plate XIV, Figures 12-14.

Represented by the posterior part of the skull and jaws with the accom-
panying molar teeth. Apex of paracone of superior sectorial in front of
middle of length of crown; base of paracone with a small tubercle in
front; no cingula; cingulum of M. i. rounded and thickened, and wider
anteroposteriorly than the middle of the crown. Internal cingulum of
M. ii. not so expanded anteroposteriorly as that of M. i.; protocone the
apex of a triangle which includes a central basin. Paracone and meta-
cone of both superior molars lost. Inferior premolar + with a small conic
cusp on the middle of the superior face of the short heel. Inferior sec-
torial with the blade a little longer than the heel. Metaconid not quite so
high as the paraconid. No cingula except a low one on internal side of
heel. Inferior M. ii. very small, grinding face nearly round, with two
low opposite cusps connected by a low transverse ridge. No cingula.
Enamel of all the teeth smooth.

The teeth of this species are about the size of the fisher, Mustela pen-
nantii.

Measurements.

Mm

Diameters of superior sectorial............... i vertical .... Ror acas fro 7
anteroposterior........... 13

Diameter of M. i superior, anteroposterior..... Moncqstaqonda spdDoOUdAGeCCD 8
Diameter of M.ii superior, anteroposterior ................200.2eesseee ees 5
VEL EI CAM pats eccie wiaie ais el ale yerane 10

Diameters of inferior sectorial................ anteroposterior........... 14
TraMSVerse.....-..--.cere 5

Diameters of inferior M. ii...............+00. 1 BBILELO DOBUCIIOB a eaeeag a. oe
transverse ...........+05. 4

This important addition to our short list of American extinct Weasels
was discovered by Mr. W. F. Cummins, to whom I take great pleasure
in dedicating it.

BOROPHAGUS, Cope.

American Naturalist, 1892, p. 1028.

Probably family Hyznidae. Second and probably the first premolars
enormously larger than the third and fourth, and consisting of a conic
anterior portion and robust posterior lobe and keel. Sectorial with a

VERTEBRATE FAUNA OF THE BLANCO BEDS. 53

short acute blade. Fourth inferior premolar present, one rooted. Third
inferior premolar molariform.

This genus is established to receive a remarkable species of carnivore
from the Blanco terrane. The typical individual of the typical species is
represented by an anterior part of the lower jaw. Probably the same
species is represented by the separate crowns of two inferior premolars and
sectorial molar and some other fragments. These teeth are closely sim-
ilar to those of the existing Hyzenas, so that I refer the genus Borophagus
to the Hyznidae provisionally, since the essential diagnostic parts have
not yet been found. The conic character of the principal premolars, and
their abrupt increase in size anteriorly, the low, almost molariform, char-
acter of the third premolar, together with the short blade of the inferior
sectorial, constitute strong points of resemblance to the Hyzenas. I re-
fer the present form to a distinct genus, under the name Borophagus, on
account of the presence of the fourth premolar.

In the Loup Fork epoch, the genus lurodon was represented by sev-
eral species, varying from the size of a red fox to that of a grizzly bear,
which performed the function of Hyzenas in the economy of the fauna, in
devouring the carcasses of the numerous large species of Mammalia with
which they were contemporary. ‘The premolar teeth of the larger spe-
cies were more robust than in the true dogs, and were useful in breaking
bones. Jn the Blanco fauna the genus Borophagus probably performed
the same function, and they carried the development of the premolar
teeth to a greater degree of effectiveness, as a mechanism for crushing
bones. They resemble those of the Hyzenas much more nearly than do
those of the species of A/lurodon, and were as robust as those of the
largest species of that old world type.

On a former occasion, in discussing the affinities of the extinct dogs of
North America,* I expressed the view that the genus Alurodon would
prove to be the ancestor of the Hyznidae. At that time no genus of
Hyzenidae was known from North America, and the genus Alurodon is
not known from the old world. ‘The transition I suggested might have
been accomplished through the old world genera Ictitherium, and Hyx-
nictis, which have been regarded as transitional between the Viverride
and Hyzenidae by Gaudry. It seems, however, that the American conti-
nent possessed in Borophagus a representative of Hyzenictis, with which
it agrees in possessing the fourth premolar. Dr. Schlosser has agreed with
my view that Alurodon is probably ancestral to the Hysnidae. This
hypothesis is, however, provisional only.

*American Naturalist, 1883, p. 224.

54 GEOLOGICAL SURVEY OF TEXAS.

BOROPHAGUS DIVERSIDENS, Cope.

Plate XIII, Figure 4. American Naturalist, 1892, p. 1028.

Represented by the anterior part of the left mandibular ramus with
two premolar teeth in place, and the alveoli of the anterior and of the
canine. Another specimen included the separate crowns of three molars,
including part of the sectorial, but the specimen is unfortunately at this
time mislaid.

Owing to the absence of the entire dental series it is uncertain whether
there are three or four premolars. The alveolus of the canine indicates
a very large tooth, with the posterior face of the root broadly rounded.
The fourth premolar has one alveolus, which is round, and is in immedi-
ate contact with that of the canine. The third premolar is three rooted,
and the anterior root is separated by a short space from that of the fourth.
The crown is obtuse and molariform, and is traversed by a low median
longitudinal keel, whose direction is diagonal to the long axis of the jaw,
and which has only a faint indication of a median cusp. The crown of the
second premolar (first?) is much elevated and veryrobust. It consists of
an anterior conic cusp, whose horizontal section at the base is a wide oval,
a lobe of the posterior margin, and probably a large keel, but this is
broken off. The posterior root is very large, its alveolus nearly equal-
ing that of the canine. J infer from this the presence of a large keel,
wider than long. This tooth has no anterior cutting edge, but an angu-
lar trace of one. The third premolar crown only reaches the base of the
crown of the second. The mental foramen is below the space between
the third and fourth premolars. ;

Measurements.

Mm.

Transverse diameter canine alveolus. ....... ccc ce cece ee cece ee neces eeeeeees 13
Transverse diameter second alveolus, P. m.ii...................--.---0--e 13
longitudinal.............. 4

Diameters crown P. m. iil ................04. auteroposterior........... 10
TTADSVEISC cc ccan teens 8

longitudinal.............. 17

Diameters crown of P. m.ii.................. anteroposterior*.......... 28
tLANSVELSE c..c 6 «sie e aeee 15

The second specimen includes a robust conic crown with a small conic
cusp at its base, and an anterior blade of a sectorial. The conic cusp is
without cutting edge. The blade has a rather short straight edge, which
is in its unworn state finely serrate. It is no larger than the correspond-
ing part in the -Hlurodon saevus.

This remarkable species was probably a scavenger, devouring the car-

*Partly estimated on account of absence of keel.

VERTEBRATE FAUNA OF THE BLANCO BEDS, 55

casses of the huge Mammalia that existed during the Blanco epoch. Its
dental structure is adapted for crushing bones, while its canine teeth
served their usual purpose of tearing into fragments the carcasses of the
camels, horses, etc., that formed its food. The corresponding parts are
similar in dimensions to those of the spotted hyena (Crocuta maculata).

FELIS, Linn.

A single species of Felidz may be provisionally referred to this genus.
The specimens which represent it consist of the second, third, and fourth
metacarpals of the left side, a second metatarsal of the same side, an ento-
cuneiform, an unciform, a calcaneum, the arch of a lumbar vertebra,
and two superior canine teeth, found together, and a scapholunar bone
found near at hand. The canine teeth indicate a mature animal.

The metapodials of the species here described are relatively shorter
than in any species of Felide known to me. There were evidently five
digits in the manus, and four in the pes. The distal extremities of the
penultimate phalanges are not unsymmetrical, as in the larger cats of the
genus Uncia, as the lion, ete.

FELIS HILLANUS, Cope.

Sp. nov. Plate XIV, Figures 1-11.

The superior canine tooth is large, but the greatest diameter is seen in
the root at its inferior third. The crown has the horizontal section at
the base a horizontal oval, much less convex on the inner than on the
outer side. There are well marked obtuse cutting edges anteriorly and
posteriorly, the anterior terminating at the base in a slightly projecting
angle. Enamel smooth.

The separate neural arch of a vertebra presents the postzygapophyses.
The articular faces of the latter are vertical, and not convex. Thespine
is of moderate elevation, and its base occupies the entire neural arch.
Its anterior edge is subacute.

The distal face of the unciform is as broad as long; its posterior process
is rather short. ‘The entocuneiform is short, narrow, and deep antero-
posteriorly, and the distal articular. surface is crescentic. ‘The metacar-
pals are rather robust, and the second is about four-fifths the length of
the equal third and fourth. The diaclast* is present on the third as well
as the fourth, as in other Felide, but that of the third is not overroofed
on the anterior side, as is that of the fourth. The facet on the anterior
side of the external proximal fossa of the fourth, shows that the diaclast
is present on the fifth metacarpal. The proximal articular surface of the

*I propose this term for the interlocking process of a metapodial which occu-
pies the external fossa of the adjacent metapodial in most Carnivora.

56 GEOLOGICAL SURVEY OF TEXAS.

second metacarpal is not so convex anteroposteriorly as those of the third
and fourth, and is openly grooved in the same direction, which is not the
case with the others. The distal trochlear keels are acute.

There are no phalanges of the first row preserved, and but two of the
second. They are rather elevated at the middle of the proximal extrem-
ity, while the shaft is depressed more toward one side than the other.
The distal face has an arc of 180 degrees, and is openly emarginate in the
longer phalange, but truncate in a short one. The long phalange is rela-
tively longer than in any feline animal known to me, equaling two-fifths
of the longer metacarpals.

The calcaneum has lost the extremity of the tuber, but is otherwise
complete. It is wider at the sustentaculum than is usual in digitigrade
carnivora, while the ectal facet is directly in the line bisecting the cuboid
facet and the tuber. External cuboid tuberosity moderate; cuboid face
semicircular, with a fossa on the inner border. The second metatarsal is
equal in length to the second metacarpal, but is more slender. Its head
is openly grooved anteroposteriorly, and displays on the inner side two
longitudinal facets separated by a groove. Hach facet shows two seat
one for the magnum and the other for the third metacarpal.

Measurements.
Mm
Length of superior canine (apex restored).............220.--e- eee veeees 60
Diameters at base of crown............-.. anteroposterior 2-1 --- To
transverse.............. aB|
Length of crown of superior canine (apex restored)..................-. 24
ILO Che WUNEONB IE Gh do cooadouLaGoadoodanonnoddueGoosOsNd HddyconsONS 13
Distal diameters of unciform................. i UU O SIO soe 2a 2
transverse. ............. 14
anteroposterior......... 12.5
Diameters entocuneiform..................-.- longitudinal ........... 9
ELANISVCISE. oi. cine ein - - 6 6.5
Length of second metacarpal .......... 0... cece cree reece eee ce eee ceceee 50
Length of third metacarpal .............. nS Rado oc veCR RO IME Saeed On 61
Length of fourth metacarpal ............ ce cece eee eet eee ee eee ee eee 61
Proximal transverse diameter, M. ¢. il......... 12. ee cette eee rete 11
Proximal transverse diameter, M. c. iii., with diaclast................... 10.5
Proxima] transverse diameter, M.c. iv., with diaclast................... 11.5
Transverse diameter of shaft, M.C. ii........ 0. cece cece eee eee eee 7.5
Transverse diameter of shaft, M. c. iii.............. 02.2 ec eee ee eee 8
Transverse diameter of shaft, M. C. iv....... 06... cece ee cence ee nee ees 8.5
Distal diameter above condyle, M. ¢. ii....... 0... ee eee ee ence eee 11.5
Distal diameter above condyle, M. ¢. iii ............ 2... c ce eee ween ees BG es)
Distal diameter above condyle, M. C. iv ............ see e ee cee ee eeeeeeee 12
Length of caleaneum from ectal to cuboid facet eee dalelate DE eSeareta ce 23
Width ati sustentaculum), . 2.22... 2 6. ence endo sc ce sccm ens clnvisnsieinslssics sie 22
Diameters cuboid facet............... 2.0005. | anteo p08 aaa ae; sa
transverse........-.-+-- 12

Depth caleaneum at ectal facet....... 0 cece ees e cece e eee ene e cnet tees teees 21

_— = oe ,

VERTEBRATE FAUNA OF THE BLANCO BEDS. 57

Depth caleaneum at middle of tuber ........ce cece ee eect ee eee c eer eeenee 16 -
proximally............. 9
Length M. t. ii.; transverse diameter ......... at middle of shaft...... 6
distally above condyle.. 10
Length penultimate phalange NO. 1....... cece es cece eee ee cee ec eee n eens 13
Width of same at condyle.... 1.2... ccc cece ewes ce nes cece eset eeeneeeee if
Length penultimate phalange No. ii........-.. 6. cee eee eee ete eee 24.
Wadth Of Same at COMGWGsh -)0 tents te l= aye esse sis) e)atobei es miaitin ele, «ila(eieiy oem ©» e)r.0 oh0 10

The shortness of the metapodium and width of the calcaneum in this
species indicate that this species was less digitigrade than the existing
species of Felis. Its dimensions were probably about those of the
cheetah (Cynelurus jubatus).

The typical specimens were found by Mr. W. F. Cummins. I name
the species in honor of Prof. Robert T. Hill, who has done important
work in the geology of the Staked Plains.

PROBOSCIDIA.
TETRABELODON, Cope.

Proceeds. Amer. Philos. Soc., 1884, p. 2; Amerivan Naturalist, 1889,
p- 193.

TETRABELODON SHEPARDII, Leidy.

Plate XXIV.

Mastodon shepard, Leidy, Proceeds. Acad. Philadelphia, 1870, p. 98;
1872, p. 472. Cope, American Naturalist, 1884, p. 524.

Dibelodon shepardii, Cope, Proceeds. Amer. Philosoph. Soc., 1884, p.
5, partim.

Mastodon obscurus, Leidy, partim, Report U. S. Geological Survey
Perso, p. 030. Pl, XXI., 1873.

A lower jaw of this species, lacking the condyles, and supporting the
second and third true molars, was taken from the bluff at Mont Blanco
from the same excavation that yielded the Pliauchenia spatula, Cope,
and within fifty feet of that at which the tooth of 7. precursor was ob-
tained. It came into possession of Mr. M. M. Cox of Estacado, from
whom I obtained it by purchase after my return from Texas. The ac-
quisition of this specimen is important as enabling me to determine the
true characters of this species, since it has been known so far only from
a last inferior molar, and possibly a fragment of a tusk, both from Cali-
fornia.

The second true molars are much worn, but they show only three
eross-crests without a rudimental fourth, as was to have been expected
from the character of the third molar. The third true molar exhibits
exactly the simple characters of the typical specimen described by Leidy;

58 GEOLOGICAL SURVEY OF TEXAS.

that is, it has four well separated cross-crests, and a very rudimental heel.

The external half of each cross-crest wears into a trefoil, while the inter- )

nal half is simple and undivided, and is a little anterior in position to
the external half. The tooth continues its width posteriorly, so that the
transverse diameters at the first and fourth cross-crests are equal. A
marked character of the species is the elevation of the anterior part of
the ramus and the decurvature of the symphysis, from which it results
that the superior face of the symphysis, or the spout, descends very
steeply to its extremity from the second true molar quite as in the proxi-
mal part of the spout of Dinotherium. It has a very short horizontal
portion anterior to the second true molar to represent the long horizontal
production in Dibelodon tropicus, Mastodon americanus, etc. The sym-
physis is also much compressed above, so that the spout is narrow. The
extremity of the spout is produced and contracted, and slightly recurved
at the extremity, and there issues from the right side a well developed,
vertically compressed mandibular tusk. On the left side is the empty
alveolus of its counterpart, which was of much larger diameters than
that of the right side. The portions of superior tusks found in Cali-
fornia are stated by Leidy to possess an enamel band, and as there are
various reasons for supposing that they belong to the 7. shepardii, I refer
provisionally the species to Tetrabelodon rather than to Dibelodon, as
heretofore.

The contracted symphysis steeply descending forwards, and expanding
downwards at the base, from a posterior elevation, distinguishes this
species from any of those of the genera Tetrabelodon, Dibelodon, or
Mastodon, known to me. Hence there is no question of its difference
from the TZ. productus, Cope, with which it was identified by Leidy,*
where the symphysis is flat and much longer. In the Dibelodon andium,
according to D’Orbigny and Burmeister, the symphysis is not elevated
behind, is produced and decurved at the extremity, and has a wide spout;
all characters quite different from what is seen in 7’. shepardii. The
symphysis is totally distinct in the D. tropicus, as can be seen in the ac-
companying plates, and the last true molar is much more complexed in
the latter. J formerly identified the species so abundant in the Equus
beds of the valley of Mexico with this species.{ This determination must
now be reconsidered, since the form of the mandibular symphysis is en-
tirely different; there is no mandibular tusk, and the last lower molar is
not identical in form,{ though I formerly thought it not so different as

*By reference to it of specimens of 7. productus from Santa Fe. New Mexico,
in Report U.S. Geological Survey Terrs., I, 1873, p. 235.

+Proceeds. Am. Philosoph. Soc., 1884, p. 5.

tA figure of this tooth is given by Felix in the Paleontographica, Vol.
XXXVII, Pl. 30, 1891.

—— ee Nee ee eee

VERTEBRATE FAUNA OF THE BLANCO BEDS. 59

to preclude the possibility of the species being identical did no other dif-
ferences exist. The differences observed in this tooth may, however, be
of specific value. The relative width of the crown is greater, especially
anteriorly, and the lateral borders of the latter are not parallel as in 7.
shepardii, but converge posteriorly, as in M. precursor. The lobes of
the cross-crests are opposite as in the latter species. From M. precursor
this tooth differs in the more tubercular and less crest-like character of the
cross-crests, and in their more profound division “on the median line,
especially in the third and fourth crests. M. precursor is zygolophodont
while the Mexican species is bunolophodont. ‘The various characters
just mentioned also distinguish the M. precursor from the T. shepardii.
There is no evidence that the Mexican species possesses an enamel band
on the superior incisors. My assertion to this effect was based on a speci-
men which presents this character which is preserved in the Escuella de
Minas of Mexico. This specimen came from Tehuichila, in the State of
Vera Cruz, from a formation which I subsequently determined to be of
Loup Fork age, so that the identity of the species with that found in the
Equus beds of the valley of Mexico is highly improbable. I therefore
refer the latter to the genus Mastodon under the specific name of @.
oligobunis, Cope. It differs from the Dibelodon tropicus in the smaller
number of cross-crests of the last molar, and their greater simplicity,
since they are not divided at all, and the external halves of the first and
second only have anterior and posterior buttresses, in some individuals
at least.

Measurements of T. shepardii.

Mm,

Length of right ramus and symphysis ...... SiS e cn OTE YrRe CHS AR ee ec ar 730
Length of right ramus to symphysis............. 0c cece cece ee eee eee eenes 515
Depth of ramus at posterior end of M. iii ...... 0... .. cece eee eee ee 135
Depth of ramus at anterior end of M. ii...... 0.0... 000 eee ee cee eee 175
Width across both rami at posterior end of M. iii.................. 0.0.0. 420
Width of right ramus at posterior end of M. iii ...................... 00. 140
Width of both rami at base of symphyses................ccceee cece ees eee 214
Width of snout at proximal end ............. ccc cc ccc eee eee ee cece eevees 65
Width of distal extremity of symphysis ...............000 cecueececeees eee 120
Heng th Offsmoubieeascmrectersoesae ne israbe ciossielehs cei eisiaine wis Glo Mics stots Bis ee medidas ware 215
Diameters) Of MiMi sen saiseiemsion aise ole cleo 2 | anbeTOPOSteriOr...-. +... ue
transverse at middle..... 75

Diatneters Of Malnesseuenen be cate aes. | UES SO IER IO RGD a Wee
transverse at middle..... 75

Diameters of right symphysal tusk........... Vertical... 0... 2.0.0.0, os
ENAMISVETSCN..erakic tie as ec bis 27

Diameters of left symphysal alveolus......... NUON Spc eee eee uf

60 GEOLOGICAL SURVEY OF TEXAS.

DIBELODON, Cope.

Proceeds. Amer. Philos. Soc., 1884, p. 2; American Naturalist, 1889,
p- 193.

DIBELODON HUMBOLDTH, Cuvier.

Plates XV, Figures 2-4; XVI, Figure 4.

Cope, Proceeds. Amer. Philos. Soc., 1884, p. 5.

Mastodon humboldtii, Cuvier, Ann. de Museum, VIII, 1896, p. 413; De
Blainville, Osteographie, Gravigrades; Gervais in Castelnau’s Voyage en
Amerique du Sud; Burmeister, Annales du Museum de Buenos Ayres.

The palate, with the penultimate superior molars of this mastodon, were
found by myself, buried with a number of bones of the skeleton. Mr.
W. F. Cummins found in two other localities two molars, probably the
last premolar and first true molar of one individual, and a last premolar

of another individual. No entire last true molar, no symphysis mandi- -

buli, and no tusks were found. It follows that the identification of this
species is not as definite as is to be desired; nevertheless I can find no
important difference between the teeth obtained and the corresponding
ones of D. humboldtii.

The penultimate molars of the D. humboldtii are figured by De Blain-
ville and the (?)first true molar by Burmeister. The last molars are fig-
ured by all the authors above quoted, and I have a perfect specimen in
the entire ramus with symphysis in my private collection from Buenos
Ayres. The only character in which the Blanco molars differ from those
figured and described as above mentioned, is the larger size of the heel,
which forms a small fourth cross-crest on continued wear. It consists of
three cusps, two on one side of the middle line and one on the other,
whose combined section is crescentic, with the concavity backwards. Its
transverse extent is about half that of the true crests. A distinct rudi-
ment of this structure is represented as existing in the D. humboldtii of
South America. The Blanco teeth can not, however, be regarded as
tetralophodont.

This species is readily distinguished from all other American trilopho-
dont species by the similarity in composition of the internal and external
halves of the molar crests. Both have lateral internal tubercles, so that
both wear into similar trefoils. The marginal portions of these trefoils
are equidistant on the opposite sides of the crown, so that they do not
come into contact on wear, while the two inner lobes of the trefoils come
into contact on wear, and completely block the transverse valleys. There
are robust but low cingular tubercles between the crests on the internal
side at the base of the crown, but these are not connected with each other,
so that there is no cingulum. There are no corresponding tubercles on

———— ee

VERTEBRATE FAUNA OF THE BLANCO BEDS. 61

the external side of the crown. There are two or three accessory tuber-
cles at the anterior extremity of the crown closely appressed to the first
cross-crest. The lateral internal lobes of the trefoils are separated from
the single external lobe by deep grooves.

Measurements of M. 2,

Mm
Anteroposterior Giameter.... 2.0 ccc se ne teers eet c eee e ese test tnnes 127
Wiidthyattinshierest atibas@re sc cins cece acl sles o> eisie.6 vies sie lersielacs era sie sis eels seis ee 72
Waidtin atiihird/ crest abibasSe..c. cccee cect c cc cscs cede ce cee evan cceeesaegee 80
BlovationmomilirQvenesty sc. vere cies lacstic se oe side ols aie'c-e clei oe eels has elneiee yleiie ee 53

The probable first true molar is unworn, and lacks the anterior border
and one-half of the anterior cross-crest. The tubercles composing the
crests are very distinct, are defined by deep vertical grooves, and con-
verge toward the median line with their apices. The cingulum passes
round the base of the second cross-crest, and between the crests is serrate,
and even pectinate. The principal cusp on one-half of the second and
third cross-crests is a little posterior in position to the crests of the oppo-
site side.

Measurements of ?M. 1,

Mm
FMDILETOPOSECTION CUANME LOT oa) nel e/sies ol ole) ciel alc) sl ricieieds) cic .c olcleboie\eleiels vel eels cis oe e's 98
Wich hati clclhexCnOSS-CTESt sy). sistsccs athens aalic se leistals ecole ie ccnys s)eysle wie ales Gua da Qala abe 59
Elevation of middle cross-crest .......... 00. cece cece eee ee eee eee e ences AT

The supposed last premolar is still more complex than the first true
molar. The enamel layer is more grooved, forming plications on wear,
and the internal lobes of the trefoils of the external series are subdivided
so as to produce on wear from five to seven lobes. An external cingulum
is developed, which sends up strong tubercles at the valleys, but is weak
at the cross-crests. There are rudiments of a cingulum on the opposite
side.

Measurements of ? P.m. 1.

Mm
Anteroposterior diameter of CrOWN ........ 00. cece cece cece eee eee eeee 78
Width at WO GeTORIELOSS-CHOSUT fees cee rine nels cieenee cee mee eens teers 50
Elevation of third cross-crest (little worn)............-...0:2eese eee eee ee 35

The only other North American elephants with double trefoils are the
Mastodon (?Dibelodon) nvirificus, Leidy, and the Tetrabelodon campester,
Cope. Both of these are fully tetralophodont. and belong to the older
Loup Fork fauna. The Dibelodon humboldtii, on the other hand, belongs
probably to a later fauna than the Blanco, viz., the Pampean of South
America, which is more or less exactly equivalent to the Equus beds. It
would not surpise me if future research would show that the Blanco spe-

62 GEOLOGICAL SURVEY OF TEXAS.

cies occupies an intermediate position in structure, as it does in time, be-
tween the M. (?Dibelodon) mirificus and the D. humboldtii. The occur-
rence of the latter species in Texas indicates a great range in latitude,
since its remains have been found hitherto principally in Buenos Ayres
and Chili. Its supposed occurrence in Mexico I have shown to be based
on a misapprehension. *

A specimen found not far from Pernambuco, Brazil, has, however, been
recently presented to the Academy of Natural Sciences of Philadelphia
by Dr. J. Cheston Morris, and this discovery shows that a tropical cli-
mate has been no obstacle to the migration of the species. The specimen
referred to includes three crests of the last true molar, which is charac-
teristic.

From its geological position, I suspect that the Mastodon mirificus,
Leidy, will turn out to be a Dibelodon.

DIBELODON TROPICUS, Cope.

Plates XV, Figure 1; XVI, Figures 1-3.

Proceedings American Philos. Soc. 1884, p. 7.

Mastodon sp., Cope, loc. cit., 1892, 123, 123.

Mastodon humboldtii?, Cuv. Von Meyer Paleontographica, 1867, Stu-
dien neb. Mastodon, p. 64, Pl. VI.

Mastodon successor, Cope, Proceed. Academy Philadelphia, 1892, p. 227.

A few yards distant from the locality in which I found the superior
molar teeth of the Dibelodon humboldtii, the head of a humerus projected
above the surface of the ground. Following the shaft downwards, I
reached a large tusk, which was lying in contact with its inferior third.
On fully exposing the tusk, I found that it was resting upon a mandible
with complete symphysis and two molar teeth on each side, but lacking
angles and condyles. At various other points on the same hill I observed
fragments of teeth and bones of mastodons. Besides this specimen, Mr.
W. F. Cummins found near Mount Blanco a last premolar of two other
individuals, and a last premolar from the Paloduro Canyon. It was from
the teeth found by Mr. Cummins that the first indication of this species
in the Blanco bed was obtained, as above cited.

The portion of tusk exposed is about four feet of the basal region.
This did not display any enamel band, but its absence from this part of
the length does not disprove its presence on the more distal region. The
question of its presence or absence must be left in doubt for the present.
The symphysis is short and is without incisors. It is nearly as short as
in the elephants, and is much more contracted than in the D. cordiller-
arum. ‘The constitution of the molar tubercles is as in that species, and

*Proceedings American Philosophical Society, 1884, p. 7.

ome

VERTEBRATE FAUNA OF THE BLANCO BEDS. 63

various species of Tetrabelodon, but the last inferior molar has five well
developed cross-crests and a prominent heel and one more cross-crest than
any of the species cited, thus resembling the tetralophodont forms of
both genera. I would have suspected that this species is tetralophodont
had I possessed only the last molars, but the presence of the second true
molar in both rami in excellent preservation shows that this is not the
ease. It agrees in the characters of its molars very closely with the typi-
cal specimen of the species from Michoacan, Mexico, described and figured
by Von Meyer as above cited. The last true molars are not fully pro-
truded, and the inference to be derived from the character of the second
molars is that that tooth would have but four crests and a keel. On this

supposition I suspected the animal to represent a species distinct from

the M. tropicus and named it M. successor, as above cited. This name is
now withdrawn.

In the inferior molars the apices of the crests are very obtuse. The
external half of each cross-crest possesses a single accessory tubercle on
each side of its internal extremity, which, together, produce the trefoil
section on wear. The internal halves of the crests possess no accessory
tubercles except on the first cross-crest, where they are present, and a
trace at the posterior base of the second. Each half is divided at the
summit and on the sides by a groove, into two lobes, which are only
superficially distinguished, and more plainly in the anterior than in the
posterior teeth. There are no cingula, but there are tubercles at the
mouths of the external valleys.

The last inferior molars support, as above remarked, five cross-crests
and a well developed heel of two tubercles. In the last two cross-crests
the internal halves are situated a little in advance of the external halves.
The general outline of the crown is that of an elongate wedge. The
principal lobes of the fifth cross-crest converge upward, but the con-
vergence is less than in the others.

The second molars are well worn, but not so as to obliterate the paitetn
at any point. On the external side the valleys remain open, but on the
internal side the adjacent enamel borders of the crest are in contact so as
to obliterate the valleys. The bilobate character of the external half of
each crest is well preserved. There is a rudimental cross-crest behind
the third, in close contact with it, which does not extend across the
crown, and which is less developed than in the D. humboldtii. The
enamel in both true molars is smooth, excepting some horizontal wrinkles
on the ends of the cross-crests.

The symphysis is short and abruptly acuminate and slightly decurved
at the apex. Its length is less than that of the second molar tooth, hav-
ing shorter proportions than in the corresponding part in D. humboldtii,
and very much shorter than in D. cordillerarum, as represented by Bur-
meister.

64 GEOLOGICAL SURVEY OF TEXAS.

Measurements.

Mm.

Geneth of symphysis man Gila). iy nctape crteetees periselenteeeitemmcleisisletetsictatsralste 120
Length from M. ii to end of Symphysis...........cccceseeveecsscesssencees 222
ORAM GLOKE GL ANTE ciacc sarees vieceis <'eloe a arene | anteroposterior. ..... a
transverse at middle ...... 65

DiamMelers\OLIMe ie prcrtetacrects Hastie see icieisiete | anteroposterior. ..... veeee 190
. transverse at front........ 70
Elevation of M. fii, at front (little Worn) 1.0... ...cce cee eect eee eee e ee ease ~ 40
Depth of ramus at front of M. jij. ........-.. cece cere Valeo zee aveset stays erarenane 190
Depth of ramus at posterior end of symphysis............eseceeeeevseereess 120

The first true molar found alone is half worn. It presents a narrow
anterior cingulum and a prominent heel of several tubercles. The last
premolar from Paloduro isunworn. The bilobation of the internal halves
of the crests is very strongly marked, as is also the trilobate character of
the external halves. The posterior inner lobe of the trefoil is lower than
the anterior inner. An anterior cingulum and narrow heel.

Measurements.
Mm.
Length, of Mi vie aii aets oe crtarstoruate ia coceinaneumporeretelsttdete cit letras eter al eteratere anaes 91
Widthiof same/at middle. ..57%.. 2 esos tere lovesaleiawe 5 soci Sieie wre, ola toforeieleneeenarstsreteransie ae 58
Trem gtihny of ein eben ai plies eregeinie ehejels bie el ievarvisicic = ateiolessts: sv eieisiate fae Meiatelevele lo eyspeeateheietets 94
‘WY Le tla sev tira ol Ch esis sis cc sc scpepdo te cas tcinc ajotelieve crtavousie os crocerrs ofovenelarttenncheveieta ele ei icee eens 58
Hlevationsof anterior Crest . 5. ccc.sie.e\cie ous cuore a0 ace" aletals cielo erowerelel sialenetateteieret ee 49

The anterior molars agree with the posterior molars in their diversity
from the corresponding teeth of the D. humboldtii from the same region.
But one side of the crown presents trefoils, and the lobes in the anterior
molar and last premolar do not display the additional plications seen in
that species. This difference is most striking, and emphasizes that found
in the true molar, since in the anterior crest of the last true molar they
are not so pronounced.

This species adds another element to the tropical American contingent
of the Blanco fauna. Its southern range extends to Peru, if, as I sus-
pect, a ramus of the mandible, with the last molar from that country,
presented by Dr. Coates tothe Academy of Natural Sciences of Philadel-
phia, pertains to it.

DIBELODON PRACURSOR, Cope.

Sp. nov. Plates XVIII, XIX.

A hundred yards from the locality which produced the specimens of
mastodons already described, Mr. Duncan Cummins found a posterior
molar of another species in the side of the bluff from which I had exca-
vated the jaw of the Pliauchenia spatula. ‘This molar tooth has lost its
anterior cross-crest, but is otherwise perfect, and is unworn.

ae

VERTEBRATE FAUNA OF THE BLANCO BEDS. 65

On the supposition that one cross-crest has been lost, the crown con- —
sists of five cross-crests, or four cross-crests and a very large heel, which
has the constitution of the cross-crests, but is transversely contracted.
The cross-crests are remarkable for their acute summits, in which they
resemble those of M. americanus and T. serridens. They are, however,
more contracted transversely, or shorter at the apex than is the case with
either of those species. In their acuteness they differ from both the spe-
cies which are found in the same formation. They have accessory ridges
on the external halves only, which would produce lobes on wear, while
the internal halves of the crests are entirely simple. These ridges have
no distinct apices, but disappear upwards in the cross-crests, from which
they are separated below by shallow open grooves only. They are want-
ing at the posterior bases of the third and fourth crests. They do not
reach the median line, but the main axis is produced beyond them to
reach it. The section of an external crest is then rather a four-lobed
cross than a trefoil. The apices of both halves of the crest descend rap-
idly to the median fissure, meeting at a strong angle a little more than
right. The edge of the internal half of the crest is slightly notched or
bilobate, except on the fifth crest. The valleys are bounded on both
sides of the crown by tubercular ledges, but there are no lateral or pos-
terior cingula. Enamel smooth. A considerable deposit of cementum
between the crests.

Measurements.

Mm
Length of last molar (anterior crest restored)......... 2.000 .ceeceeevecece 160
Width same atisecond Crest). cs. covecelccedstecdeccccccudeteececsvcleeccss 68
eT HaRAMen ate GHNCLESE cis) <teis,0 eis pie gee vie cra w'srere,o.o'e-ale,e ersisSureiolee oarelelsieelones 4]
He vatiOnporSCCOMd CREShs cais\clect-alere es 4 anincinrsie a toons vi cieie Siele eloleilereceaiw dials 54.
Bile aIOn Ob fib CTS ti skisis;<|vieeials's cere eed care ernlgie’e aicis v sie cisieie Sie wibeiewiciaee ees 30
NATH On apex: Of SCCOM'CTreSt s 025... se we cee cece ee cee weccenccedeuceees 29
WiiibRotapexstOP TithiCresti.c0 i. ccc cecccecscicesss cat ccrcccectacectes oa)

The tusks of this species are unknown, and I refer it to the genus
Dibelodon provisionally only. It must be compared with the 7. shepardii
and the Mastodon americanus, as the species to which it bears the nearest
resemblance. It differs from the former in the five cross-crests, which are
more elevated, more contracted in both directions and more acute. The
outline of its base is more wedge-shaped. It differs from the M. americanus
in the same features, and in the presence of accessory ridges of the external
half of the cross-crests. Of all the Mastodons of America it approaches
nearest to the M. americanus in the simplicity and acuteness of the
crests, and further information as to its characters will be welcome, in
view of a possible relationship with the latter species.

5— Geo]

66 GEOLOGICAL SURVEY OF TEXAS.

DIPLARTHRA.

The only species of this order which have been discovered in the
Blanco beds belong to the genera Equus, Platygonus and Pliauchenia.
No trace of rhinoceros or tapir has been observed.

EQUUS, Linn.
EQUUS SIMPLICIDENS, Cope.

Plate XX, Figures 1-3.

Proceedings Amer. Philos. Society, 1892, p. 124. Annual Report
Geol. Survey of Texas, 1891 (1892), p. 252.

Inferior molars and bones of this species are abundant at Mount
Blanco, but superior molars are less common, in a well preserved con-
dition. The exploration of 1891 yielded only two superior molars which
are determinable, and that of 1892 has yielded three which are determin-
able, though fractured, but none in better condition than the type. Ishall
therefore confine my remarks on the present occasion to the inferior
molars.

In a former paper I have given a synopsis of the distinctive characters _
of the superior molars of the species of the genus Equus*. I now men-
tion characters which distinguish the inferior molars of some of the
species of the true horses which are identified by their undoubted asso-
ciation with superior molars.

I. Metaconid and metastylid separated by a sharp entrant-

ang ular: GYOOWC «ik cis rissa sielabers telat a idics fol eist apeve ents E. simplicidens.
IJ. Metaconid and metastylid separated by an open gutter
as wide as the former at the middle of its depth..... E. occidentalis,

E. argentinus (teste Burmeister) EL. montanus, E. caballus.

Ill. Metaconid and metastylid separated by a flat channel
much wider than each of the former...... E. eurystylus, E. minutus
The above character distinguishes the inferior molars of the EH. sim-
plicidens constantly, as I observe it in the entire series of two animals,
and numerous isolated teeth. From the South American Hippidiums, as
represented by Burmeister, they differ as they do from the species of
three-toed horses of the Loup Fork. The latter have a comparatively
small anteroposterior extent of metastylid and metaconid, and only a
slight concavity between them on the inner side of the crown. No
bones or teeth of the three-toed horse were found in the Blanco terranes.
Well preserved incisors show that this species is a true Equus, and not a

Tomolabis.

*Proceedings American Philos. Soc., 1884, May.

VERTEBRATE FAUNA OF THE BLANCO BEDS. 67

EQUUS CUMMINSII, Cope.

Sp. nov. Plates XX, Figure 7; XXIII, Figure 1.

Three superior molars represent this species. They were found at
different localities in the neighborhood from which we obtained the
teeth of the HZ. simplicidens. ‘They represent an animal of considerably
smaller size than the latter, measuring with the HE. tau and LE. semi-
plicatus. Their enamel borders are entirely simple, as in EZ. simplicidens
and are hence different from those of the #. semiplicatus. It differs from
both the EZ. simplicidens and the EH. taw in the prominent convexity
of the internal wall of the paracone and metacone, from which it results
that the external border of each lake is deeply concave, and the horns
appear to be strongly produced. The protocone has a very short an-
teroposterior diameter, in which it resembles the #. simplicidens, LE.
crenidens and E. stenonis, and differs radically from the H#. taw and
the other species of the Equus beds. It is not bilobate or grooved on
the internal face. There is an angle of the posterior border of the
anterior lake which represents the loop, but no other complications of
the lake borders, except that in one specimen there is a notch in the
anterior border of the posterior lake and a trace of a notch on the remote
borders of both lakes.

The crowns are well worn in two of the molars, but that the characters
of the enamel plates are not due to wear is shown by the third specimen,
where the crown is 47 mm. long. The measurements of the best pre-
served crown are: length, 33 mm.; transverse diameter, 24 mm.; antero-
posterior, 24 mm.

The subcylindric character of the paracone and metacone approach what
exists in Hippidium and some species of the three-toed horses. The
Species is named in honor of Mr. W. F. Cummins, who has done so
much for the geology and paleontology of Texas.

EQUUS MINUTUS, Cope.

Sp. nov. Plate XX, Figure 8.

This species is represented by an inferior molar from near the middle
of the series from Mount Blanco. Some other fragments of teeth of the
species were obtained, but I can not at this writing place my hands upon
them.

The inferior molar is narrowly hypsodont, and has apparently had but
a thin cementum investment. This appears probable, from the fact that
it is as thin where protected from weathering as where exposed to it, i. e.,
in the groove between the external columns. The inner side of the
crown shows marked peculiarities. The metaconid and metastylid are
appressed to the hypoconid and protoconid, and are spread widely apart

68 GEOLOGICAL SURVEY OF TEXAS.

so as to be connected by a narrow anteroposterior isthmus, and separated
on the internal face of the crown by a wide channel which has a greater
anteroposterior diameter than the metaconid and metastylid respectively
near the apex of the crown, and an equal width at the base of the crown.
The hypostylid is also appressed to the hypoconid and has a recurved
posterointernal angle, which forms an acute ridge bounding the internal
face of the crown posteriorly. This incloses with the metastylid a flat
open gutter as wide as the metastylid. A sharp ridge marks the internal
face of the anterior border, but it is closely appressed to the metaconid,
which it does not equal in elevation.

Measurements.
Mm
Length) of crown preserved) och slic, sce. - oe eels mie rei seineteie eisai s eles. ers 37
Anteroposterior diameter at middle .................. cee cece ee eee eee 16.5
Transverse diameter at metastylid ............cc.e cece cc cecrencececaecees 8
Transverse diameter in front of metastylid ................-2-. eee weeeee 6

This species differs widely from any horse in the characters of its infe-
rior molar. Besides the flattening and anteroposterior extent of the
metaconid-metastylid, it is peculiar in the large size and internal flatten-
ing of the hypostylid. It is this flattening which causes the wide flat
channel of the internal face, which equals in width that between the met- °
aconid and metastylid, and is more sharply defined. The Equus minutus
is also the smallest known species of true horse, as its teeth do not exceed
in size those of a sheep.

PLATYGONUS, Leconte.

The species of this genus have been hitherto found in the cave forma-
tion of the Eastern States and Pleistocene deposits of Mexico (Duges).
It is therefore of interest to find it in the older horizon of the Blanco.

PLATYGONUS BICALCARATUS, Cope.

Sp. nov. Plate XIII, Figure 5.

The remains of this species which have been obtained so far include
only portions of the last inferior molar, and the superior canine which
lacks most of the crown, and which were found together, and an inferior
canine found atanother place. These specimens display distinctive char-
acters, and as they indicate an important peculiarity of the Blanco fauna,
it is necessary to describe them.

The inferior molar lacks the anterior crest. The posterior crest and
heel display characters that distinguish it from the corresponding parts
of the P. compressus. The talon consists of two principal cusps, which
are connected by a cross-crest, as is the case with the other cusps of the

VERTEBRATE FAUNA OF THE BLANCO BEDS, 69

crown. The P. compressus has but one cusp in this position, while the
species of Dicotyles possess two which are disconnected. The root of the
canine is not grooved.

This peccary is characterized by the acuteness and the posterior carina-
tion of the cusps of the posterior crest (hypoconid and metaconid), which
are subequal, and for the prominence of the cusps of the heel. Of the
latter the internal is the more elevated, and it sends an angle posteriorly
to join the apex of a posterior cingulum, which presents a right angle
upwards. ‘The external cusp is elevated, but less so than the internal,
and has a transverse angular apex. This joins a posterior external angle
of a cusp of intermediate elevation, which is appendicular to the internal
cusp at its anterointernal side. A strong rib ascends in front of the lat-
ter on the posterior face of the posterior cross-crest, which terminates
just below the protoconid-metaconid noted. The metaconid presents a
keel on the posterior face which incloses a groove with the median verti-
cal rib just mentioned, and another groove corresponds to the former on
the posterior face of the hypoconid. No external cingulum; enamel
smooth.

Measuremenis.

Mm
Me VaAttORVOL PLOLOCOMIGE ceric. oe cc ces, yee ve'sin ce sieia eco ee e ways Saeed eae vine ne ciewes 15
US VALLON OMIM TACODIG ss circ)s sin inverse classien wie aaclete sens cccccesce ce cceeanens 15
MIS vablOnVOh MY POCONIG) Vee siccel-celsieecileccrcec ances eriewecewened ea Seer 11
CMH Oda ta OME sarees afte eters <ielense Jasermsicieinpaie Geis (ele eraiaieien slecieales 4 velweeie sees ss 6
RUVSr Ht FeO fea etll © Thee terse rays orepeliet love eneles cuancyaisiove aie sie\cvelcisiale sleisleversssvataoenaiealcisie. evlelboaieus-<-8 7
Width of posterior cross-crest ........ 2 .cccce cece ce sees cece esse ect enetecs 9

The superior canine has the triangular section of the known species of
the Dicotylidz, the anterior face of the root being about half as wide as
each of the other faces. It is separated from these by obtusely rounded
angles. It is slightly concave or grooved, but the groove is filled with
cementum for part of its length. No lateral grooves.

Measurements.
Mm
Mencth of roptehO ase QReTONN see cece kia c jonas o\es.t «dine aieainn his ah wea e es 45
Diameters at base of crown ................-- | anteroposterior............ 16
CUANSVETSE) 5. «ni cu)elspeta cre eis « =e 11

The inferior canine was obtained by Mr. Cummins during the season
of 1891, and belongs to a rather smaller individual than the one above
described. The apex of the crown is lost, but the remainder has the
usual triangular section, and its surface is without grooves. The root is
grooved posteriorly unsymmetrically, one side being much more con-
tracted than the other. Length of specimen on outside of curve, 73
mm.; diameters at base of crown, anteroposterior, 15 mm.; transverse,
11 mm.

70 GEOLOGICAL SURVEY OF TEXAS.

The molar tooth is about the size of that of. the P. compressus, Lec.,
while the canine is more robust than any specimen of that species which
I have seen. The corresponding parts of the P. vetus, Leidy, are un-
known. The P. alemanii,* Dugés, from Mexico, is apparently about as
large as the P. vetus, Leidy, and exceeds somewhat the present species in
dimensions. Casts of the first and second inferior molars of the P.
alemanti were kindly sent me by Dr. Dugés, and these display a basal
cingulum, which is not present in the last molar of the P. bicalcaratus.
The posterior faces of the cusps are not keeled.

PLIAUCHENTA, Cope.

Proceedings Academy Philadelphia, 1875, p. 278.

Report U. S. G. Surveys W. of 100th Meridian, IV, p. 340, 1875;
American Naturalist, 1886, p. 621.

Camel bones are abundant in the Blanco beds, and their dimensions
indicate the presence of two species. But one of these is represented in
the collections by specimens sufficiently perfect for determination, and
this is a large species of the genus Pliauchenia. This genus has hitherto
obtained only in the Loup Fork beds of Santa Fe, New Mexico, where it
is represented by species of considerably smaller dimensions than the one
now under consideration.

PLIAUCHENIA SPATULA, Cope.

Sp. nov. Plate XXI, Figures 1, 2.

This camel is represented by a mandible which lacks all posterior to the
coronoid process of the left ramus and all posterior to the second true
molar of the right ramus. Well preserved representatives of all the
teeth are preserved.

The dental formula is that of the P. humphresiana, Cope, viz.: I. 3;
C.;z; P.M. 3; M. 3. The canines are large and distinct in character
from the incisors; the fourth premolar is separated from the canine and
from the second premolar by long diastemata, and is caniniform. The
second and first premolars are without internal valley. The last true
molar has a well developed third column.

The mandibular rami are compressed and of moderate depth, and the
symphysis is a little longer than the series of true molar teeth, and its
posterior extremity marks the anterior third the distance between the
fourth and second premolars. The incisive portion of the mandible is
more expanded than in the cameloids generally, to accommodate the
large canine and incisor teeth. The region of the masseteric fossa is
concave outward, and is thin; the anterior base of the coronoid process

*La Naturaleza Mexico, 1887, I, p. 16, plates I, II.

—

VERTEBRATE FAUNA OF THE BLANCO BEDS. 71

is, on the contrary, robust. There is a large foramen mentale, which is
below the posterior border of the fourth premolar. The inferior face of
the symphyseal region presents a deep groove on the middle line distally
between the roots of the median incisors.

The median four incisors stand on a nearly transverse line, while the
external ones are sublateral. In their present state of wear the masticat-
ing surfaces of the middle pair form very wide ovals, with the longer
diameters converging posteriorly. The surfaces of the second incisors
are narrower and are acuminate exteriorly, while those of the third are
still narrower and more acuminate externally and posteriorly. The ca-
nines are very robust, and point forward, upward and outward. There
is an enamel ridge on the outside of the oblique anterior face, and there
is a less prominent ridge on the apical part of the middle line posteriorly.
Between these crests the external face is much more convex than the in-
ternal one, and the latter exhibits a shallow groove just behind the ante-
rointernal keel.

The fourth premolars have about half the linear dimensions of the ca-
nines, and the crowns are compressed and present cutting edges anteriorly
and posteriorly near the apex. The internal walls of the other premolars
and molars are less deeply grooved than the external walls, but they are
not nearly so flat as in the Holomeniscus hesternus. ‘The internal walls of
the premolars present a gentle concavity, with an internal incurvature at
the anterior apex. The external walls present two concavities, a long
anterior and a short posterior. The posterior end of the crown is nar-
rowed in p. m. 5, and truncate in p. m. 7 The true molars increase rap-
idly in size posteriorly. The first differs from the second and third in
lacking vertical folds or ridges at the anterior and posterior extremities
of the first and second columns, which give the anterior and posterior ex-
tremities of the latter respectively an incurvature. The same rib is pres-
ent on the internal side of the posterior extremity of the third lobe of
the last true molar. There are no cingula on any of the teeth. The en-
amel is everywhere longitudinally roughened, except where polished by
use.

Measurements.
, Mm. Mm.

Pili. Hol.
spatula. hesternus.

Length of ramus from posterior extremity of M. iii. to incisive

adiveolar bord Ckiicrererrctetctersteeierctetetets siete sisters ose veisisievs 8,6) Si oavele tie 401 302
ene th: of symphysisnens escapee seers ce cued eee eens 150 90
Width of mandible at I. iii. inclusive ...................-..55. 95 57
Width of mandible at P. m. iv... ........ cece cece cece eee cence 65
Length from alveolar border to canine (inclusive)............. 60 55
Length from canine to P. m. iv........... ccc ecee cece ee ee sees 23
ene th-from canine to Bom. i. ya -c-ice nsec ticieys «ac a enicle sleds sel 145

Length from canine to P. M.i..... cc. cece cee cece eee eens 168 85

72 GEOLOGICAL SURVEY OF TEXAS.

Mm, Mm.
Pli. Hol.
spatula. hesternus.
JongGw lina nrereiasalel tienes 30 52
Diamevers Weal ee cos ces seeks transverse at middle....... 17 19
anteroposterior at middle.. 14 16
longitudinal .............. 25 39
Diameters Deis emcperectetcie cies: transverse at middle ...... 22 12
anteroposterior at middle. . 8 6
Hoye CNM S 5 ho asosaeac 25
Diameters P. mi. iv..02.c.secess-s anteroposterior ........... 17
GHATS VIELSC iso lc ale vie'siste e'ee sels 12
Diameters P. mM. U1 0... tu . ee eee | anteroposterior ........... 23
TRANS VCLSO 22 opie’ ale cisjajeaeia snow 10 sTaors
Diameters;E. Mt. se ace eee | anteroposterior ........... 29 27
TEANSVELSO Lire Soci aerejereigianstc 13 16
Diameters i: coh eee seee | anteroposterior ...--..+.%. 35 38
TLANSVETSCs cmcale: chslemieebte ete 22 19
Diameters Mie. cite acme ene 1 anteroposterior ..........: 45 44
TrANSVCTSC! oy ocnnmise eee 25 20
Diameters M. iii................. AnLET Op Oster ORS peas GS BE
tLANSV.CTSC scx. arte oerclam oes 24 16
Depth ramus half way between C. and P. m.ii................ 52 42
Depth ramus at front of M. ili ........ 2... cece we cect cece scseee 82 74
Thickness ramus at end of M. fii.... 2.2... cece cc cece eee 45 28

As compared with the two species of Pliauchenia already described,
the much superior dimensions readily distinguish the P. spatula. It farther
differs from the larger of the two, the P. vuleanozum, Cope, in having the
premolar diastema at least double the length. This is, in fact, the largest
species of camel yet discovered, exceeding the Camelus dromedarius, L.,
and the Holomeniscus hesternus, Leidy, which agree in dimensions by one-
fourth. Prof. F. W. Cragin* has described a large lama from the late
Cenozoic of Colorado and Kansas, under the name of Auchenia huer-
Janensis, whose dimensions about equal those of the two species men-
tioned. According to Cragin, the dental formula is that of the genus
Auchenia. The last true molar is also represented to be smaller than the
penultimate, which is, if true, an exceptional character. I suspect, how-
ever, a typographical error.

The relatively wider symphyseal region of the mandible also dis-
tinguishes this species at once from the Procamelus robustus, the Holo-
meniscus hesternus, and the known camels and lamas.

The mandible of the Holomeniscus hesternust above measured is from
Austin county, Texas, and has already been referred to by me in the
annual report of the Geological Survey of Texas, 1891, p. 251. It is the
best preserved specimen of this species yet obtained, and displays various
peculiarities. One of these is the procumbent and overlapping position

*American Geologist, 1892, p. 257.
{Plate X, Figures 3, 4.

Oe

ee a i

VERTEBRATE FAUNA OF THE BLANCO BEDS. 73

of the incisors, the second overlapping the first, and the third overlap-
ping the second still farther. Another peculiarity is the small size of the
canine and its separation from the I. iii by a distance of 23 mm. The
molars are very flat on the internal face, and the crowns have a relatively
smaller transverse diameter than in the Pliauchenia spatula. The ramus
is much lighter than in that species or than in the camel.

I excavated the specimen of Pliauchenia spatula from the side of a
bluff near Mount Blanco, Texas.

SUMMARY.

The species of the Blanco fauna described in the preceding pages are
the following:

TESTUDINATA. 2
Testudo turgida, Cope.
‘¢ pertenuis, Cope.
AVES. 1
Crecoides osbornii, Schuf.
EDENTATA. 1

Megalonyx leptostomus, Cope.
CARNIVORA. 3

Canimartes cumminsii, Cope.
Borophagus diversidens, Cope.
Felis hillanus, Cope.

PROBISCIDIA. 4

Tetrabelodon shepardii, Leidy.
Dibelodon humboldtit, Cuvier.
‘¢ _ tropicus, Cope.

‘¢ precursor, Cope.

DIPLARTHRA. 5

Equus simplicidens, Cope.
‘¢ cumminsii, Cope.
“minutus, Cope.
Platygonus bicalcaratus, Cope.
Pliauchenia spatula, Cope. —
otal mumber oti Sspeciess mate seas eit sieict sae aches wile c/a elev 16

74 GEOLOGICAL SURVEY OF TEXAS.

The stratigraphic significance of these species is as follow: In the
first place all of them are peculiar to this horizon. In the next place
the genera have the following distribution:

From base of Miocene to recent ............ccsececeececes is stereisteisiels Raaterave 2
From Loup Fork to Equus beds, inclusive. ......... cece cece ee eee eee eee al
Loup Fork only ix <0 cisciesetegcis sie sivio esis | aeldunintisidareh Gee Ieee eee Tiotiepeela
Hquus bed. to: recent, MCluUsive soi. «,iaioi0 cin wicjere's wicrarers1e 0/aie ace as ayeyetoheteeateper eaten 1
Equus bed Only. oc ih.< ct cine shoo giteineis one sores oles eee ae eee 2
Peculiar to ‘the Blanco is.) (isos carne wae eata in aia a ahs Gul maiere diate oe Relea 3

TOGA. sa iv Siti Srerernsereca. alate qhaiiaretel aden eta ere eosietele rey qudela aleter ce aruis cust cartaleiels casters 11

Thus five genera occur in the Loup Fork, four in the Equus bed and
not in the Loup Fork, and three are peculiar, while three genera still
exist. This statement indicates the intermediate character of the
horizon.

In first characterizing this fauna, I pointed out the occurrence of the
genus Equus in connection with mastodons with molar teeth of the
angustidens type as a relation not previously observed on the North
American Continent. I had, however, previously shown such a co-
existence in the ancient fauna of the valley of Mexico. Three species
of horses coexist there apparently with the Mastodon oligobunis, provided
the specimens preserved in the Mexican museums really came from the
same horizon. While this coexistence is possible, it is at the same time
not yet demonstrated by exact observations on the stratigraphic position
of the fossils. No such association has been detected in the Equus beds
in North America. Should it be proven to have actually existed in
Mexico, a possible antiquity somewhat earlier than that of the Equus
bed of the north may be indicated for the bed at Tequixquiac.

CHAPTER TV.

THE FAUNA OF THE EQUUS BEDS.

The Equus beds form the superficial formation of the country at vari-
ous points on the Staked Plains and about its eastern escarpment. They
are always to be distinguished by the presence of Hlephas primigenius
when other forms less easily preserved are not recognized. Mastodon is
always absent from Texas localities so far as yet observed, as in Oregon.
The terranes are more generally sandy than are those of either the Blanco
or Loup Fork epochs. In passing north from Big Springs, we first
definitely identified the Equus beds on Wild Horse creek, a tributary of
the Colorado, where they rested immediately on the Trias. Mr. Cum-
mins discovered a tract of the same on Rock creek, a tributary of the
Prairie Dog head of the Red river, on the Tule canyon, and from this
locality most of the specimens described in the following pages were de-
rived. The identification of species is interesting as showing the com-
plete difference which exists between this fauna and that of the Blanco
epoch.

THSTUDINATA.
TESTUDO, Linn.

As no determination of tortoises has yet been made from undoubted
Equus beds, it is of interest that two species of terrestrial habits were
obtained by Mr. Cummins. ;

TESTUDO LATICAUDATA, Cope.

Sp. nov. Plate XXII, Figure 1.

This tortoise is represented by a nearly entire left epiplastral bone and
a greater part of the right xiphiplastral. As these pieces present the
characters which define species of ‘Testudo most readily, I can describe
the present form and compare it with its congeners, in spite of the absence
of other parts of the skeleton.

The borders of both the elements in question are robust, and the lip
of the epiplastral is quite large. The mesoplastron is quite thick, but
the middle parts of the xiphiplastron are rather thin. The hyoplastral
sends a strong gamphosis into the epiplastral within the border, and the

76 GEOLOGICAL SURVEY OF TEXAS.

hypoplastral does the same into the xiphiplastral. The projecting lip of
the epiplastral is marked off by only a slight constriction of the external
border from the rest of the bone. Its free border is doubly convex,
owing to the presence of a concavity near the middle. The posterior
border of the lip is very much elevated, bounding in front a strong
thoracic excavation. This raised border descends rapidly, and is obsolete
from the middle to the posterior border of the epiplastral. An angular
ridge bounds externally the convexity of this part of the superior sur-
face, disappearing opposite the point where the internal appears. The
depth of the lip at the internal base is equal to its anteroposterior length
from the same point. The inferior face of the epiplastral is flat and
not turned upwards, as in 7. polyphemus, and the inferior surface of the
lip exhibits two shallow longitudinal fossze, which extend to the border.
The gulo-humeral scutal suture describes a segment of a circle forwards
and cuts across the anterior part of the mesoplastron.

The xiphiplastron is characterized by the wide divarication of the
posterior angles, whose external border is continuous with that of the
posterior lobe of the plastron. The posterior median emargination is
very wide, and the projecting angle is broadly rounded. The ridge
which borders the external level of the lobe reaches the free border be-
hind, external to the median suture. The femoro-anal scutal suture is
nearly parallel with the border of the emargination, whence it follows
that it leaves the median suture at a right angle, and that the anal
scutum is much wider than long. ‘The area of this scutum is thickened
along the’anterior border and diagonally across from this to the median
suture. The surfaces are smooth. Scutal grooves well marked.

Fragments of costal bones are rather thin, and their surfaces are per-
fectly smooth.

Measurements.

Mm

Measurements of lip at gulohumeral suture. . | anteroposterior........... 57
tYaANSVELSe .......--.eeee 73

Thickness of lip at thoracic border...........2 see ee eee ec ween ene neces 44
Length of epiplastral bone (diagonal) .............--+2+.----+0+ sees eee 138
Thickness of border of same at hyostermal suture............0...-ee0.05- 20
Length of xiphiplastral (diagonal). ..............-2-. + +e eeeeeeeeseeee eee 157
Thickness of border of same at hyposternal suture ..................-+6- 28
Width of posterior median notch of plastrom ..........-...-...-...+.--+: 122
Depth of posterior median notch at plastron ............----..-e.-0-.--- 80
Diameters of anal scutum................-+- i anteroposterior .......... 48
tramsverse..............-- 98

This species is not without resemblance to the 7. polyphemus. It is
much more robust, and the posterior plastral angle is more developed.
The anterior lobe of the plastron is not recurved in T. laticaudata and
the lip is not festooned on the border in the existing species. As com-

FAUNA OF THE EQUUS BEDS. vids

pared with 7. hexagonata of the same horizon or locality, there are several
differences of importance, which are mentioned in the description of the
- latter, which do not seem to be explicable on varietal or sexual grounds.
Rock Creek; W. F. Cummins (No. 46).

TESTUDO HEXAGONATA, Cope. »

Sp. nov. Plate XXII, Figure 2.

Represented by an entire chelonite; a considerable part of the plastron,
with fragments of costal bones of a second individual; and fragments of
plastron and carapace of a younger individual of probably the same
species.

The chelonite is that of a species having much the form of the 7’. poly-
phemus and of the T. pertenuis of the Blanco bed. That is, it isa de-
pressed, rather short oval, with wide extremities. The plastron is flat
and not sloped upward, as in 7’. polyphemus, and the lip is relatively less
prominent than in that species. As compared with 7. pertenuis the lip
of the plastron is less abrubtly contrasted with the rest of the anterior
lobe border, and the posterior lobe is less deeply emarginated. The size

_is much less; but the value of this character is not now determinable.

The lip of the plastron has a simple, regularly rounded outline, which
is distinctly set off from the rest of the anterior border. The thoracic
cavity excavates deeply its posterior border, so that the superior edge of
the latter overhangs it. This border soon fades out posteriorly, and
there is no angular ridge external to it posteriorly, as in 7. laticaudata.

The posterior lobe is rather deeply notched, and the angle bounding
the notch on each side is quite prominent; much more so than in JZ.
laticaudata, but not so much as in T. pertenuis. The external border is
distinctly notched at the femoro-anal suture, and is turned outwards
toward the apex of the posterior angle, which it is not in T. laticaudata.
The external ridge or border of the abdominal cavity reaches the median
suture at the fundus of the notch.

The mesoplastral bone is a transverse hexagon, the lateral angles being
truncate. The borders so produced are shorter than the other four,
which are equal. The gulo-humeral scutal suture is straight and crosses
part of the mesoplastron. ‘The humero-pectoral suture approaches, but
not very nearly, the pectoro-abdominal at the middle line. The abdomino-
anal suture is, as in 7. laticaudata, parallel in the corresponding border
of the xiphiplastral notch, and therefore forms an acute instead of a
right angle with the median suture. The posterior free marginal bones
are not stout. In one belonging to the presumed third specimen, the
supero-external surface is concave on each side of the scutal suturé, and
the free border is entire. A part of the anterior border of the carapace
not far from the middle line is slightly recurved at the edge. Below and

78 GEOLOGICAL SURVEY OF TEXAS.

within the edge it is much thickened and displays three surfaces. These
are: first, a flat level extending to the border; second, a flat face look-

ing downwards; and third, the concavity forming the superior wall of

the thoracic cavity. Surfaces everywhere smooth.

. . Measurements of No. 1.

Mm
Diameters of plastron .............00.00+--0% | anteroposterior .......... 365
transverse .....-:...... z-. 310
Diameters of anterior lobe of plastron....... | anteroposterior .......... 88
tramverse!) Ast. oe cee 186
Diameters of posterior lobe of plastron....... | HURCLOBORIGMIOR. = 2eae 110
: TEANBVETSE coc 'em «ccc sicieicicis 240
Wadth:of posterior notch of (plastrome. a. seecece et eee ee eee 70
Depth of posterior notch of plastron..............ceeeeec cent cee ceeeeece 25
Length of epiplastron (diagonal) 2.2.0... 0.6... eww esse waren eseceess 87
Width of lip Ciotal)tat base i :8 7 i.e scccace cates reece cee ee eee 90
Gength of lipon middle line above... 1.0. ot sciences etree relate 40
Thickness of lip at fundus of thoracic cavity ............-.seeeseeeeeneee 27
Diameters of inferior aspect of mesoplastron . | anteroposterior........... 58
tLaANSVELSE:. - 2.20 ose ee 80

Distance between humero-pectoral and pectoro-abdominal scutal suture on
middle line.......... aelajc tea; wie loravc hie /ehotejeherelay | areraperalaieee cacieto metals ates eieiate Ieee 25

The lip of the plastron is not produced and bifurcate, as in T. agassizii
(from S. E. California), but the posterior lobe is quite similar to that of
the latter species. The posterior lobe of the TJ. laticaudata is inter-
mediate in proportions between those of 7. hexagonata and T. poly-
phemus. Both of the extinct species may belong to the genus Xerobates,
Ag., but this can not be determined until the crania are discovered.

The specimens of this species are smaller than the single one which
represents the 7’. laticaudata. ‘Though allied to the latter, the forms of
the lobes of the plastron display too many differences to permit me to
regard them as identical.

Rock Creek; W. F. Cummins.

EDENTATA.
MYLODON, Owen.

MYLODON ?SODALIS, Cope.

Bulletin U. S. Geological Survey Terrs., 1878, p. 385.

The distal part of a femur, lacking part of the internal condyle and
adjacent epicondyle, represents a gigantic species of Mylodon. At pres-
ent it is not possible to determine exactly its specific relations, but its
association with the species of the Equus fauna renders it possible that it
is the animal which has been found associated with the same fauna in
Oregon, and which I haye named as above. The measurements of the

FAUNA OF THE EQUUS BEDS, 79

part: preserved are about equal to those of the IM. robustus, Owen, from
Argentina. The transverse extent of the condyle is about 210 Mm. (re-
stored), of which the popliteal fossa is about 60 mm.

Since the species was described, I have received from Mr. George
Duncan, of Paisley, Oregon, an imperfect symphysis mandibuli from
near the original source of the M. sodalis, which presents characters ap-
propriate to that genus and species. It is accompanied by a symphysis
of a large peccary, the first found in that horizon and locality.

PROBOSCIDIA.
ELEPHAS, Linn.
ELEPHAS PRIMIGENIUS, Blum.

Remains of this species are quite abundant in the Equus beds of the
Staked Plains and neighborhood, but are generally in a fragmentary
condition. The teeth from Rock creek are neither thick plated nor thin
plated, but are much as in the typical variety of Z. primigenius, and some
plates are slightly crenate, while others are plain.

DIPLARTHRA.
EQUUS, Linn.

As elsewhere in the Equus beds, several species of true horse occur,
and they are represented by numerous specimens of all parts of the
skeleton. No entire skeleton has been found, and until this is done it
will be impossible to associate positively the bones with the appropriate
dentition. The superior molars may be distinguished as follows:

a. Smaller species; molars 2525+ mm.

AM OOLGCLS SUPE 6 cise cee oe use aie ee ee ne eos tee oe E. tau.
Enamel borders, complicated at middle of crown....... E. semiplicatus.
aa. Larger species; molars 3035+ mm.
Enamel borders, a little folded at middle of crown......... Hi. excelsus.
Enamel plates much complicated on both anterior and pos-
CETLOUs Ace a WOL GOES raemr et taers ciate ere-sitcn so vine ele «6 @ emesis EH. major.

EQUUS TAU, Owen.

Philos. Trans. Royal Soc., 1869, p. 565; Equus barcenwi, Cope, Pro-
ceeds. Amer. Philos. Society, 1884, p. 15.

A single superior molar from Tule Canyon. ‘This tooth is perfectly
straight, and presents very simple enamel borders, and the anterior lake
has an imperfect loop. The crown is slightly curved, both transversely
and posteriorly. I have already indicated this species from beds near
San Diego, in southwest Texas.

80 GEOLOGICAL SURVEY OF TEXAS.

EQUUS SEMIPLICATUS, Cope.

Plate XXIII, Figures 2, 3.

Sp. nov. Equus fraternus, Leidy, Cope, Am. Naturalist, 1889,
p- 161; not of Leidy.

Represented by two superior molar teeth from the Tule Canyon, found
by Mr. Cummins, and by two superior molars in my private collection
from San Diego, in southwest Texas, from Mr. Wm. Taylor.

These teeth indicate a species of about the dimensions of the H#. tau,
but characterized by a greater complexity of the enamel foldings. These
complications are confined to the adjacent or median borders of the lakes,
the remote borders being simple or marked by a single emargination.
There is no distinctly defined loop of the posterior border of the anterior
lake, but its place is taken by three smaller loops (in one south Texas
tooth by two), and external to these are one or two other folds. There
are two or three emarginations of the opposed border of the posterior
lake. In all the Texas specimens the anteroposterior diameter of the
protocone is more than half that of the grinding face of the crown. This
character places the Equus semiplicatus in the same group as the LE. excel-
sus and E. taw. From the former its inferior size distinguishes it, as
well as the closer plications of its enamel borders. Some specimens of
the larger species, however, approach it in this respect.

Measurements.
. Mm
Diameters superior molar (Tule Canyon).... 1 PE SEO MOSES gaa A ee
transverse. ........-..0000- 25
fs f£ 4 ante LOT Aisne ete
Diameters superior molar sp. from San Diego SUDO D a
transverse ................ 27

The crowns of the Tule specimens are rather short and are not curved;
the least worn San Diego specimen has a long crown, which is slightly
curved anterposteriorly, but not transversely.

The characters of the grinding face resemble those of the E. conversi-
dens, Owen, so far as the latter can be understood from Owen’s figures.
But in that species, according to Owen, the crowns are transversely
curved, while in EZ. semiplicatus they are straight.

EQUUS EXCELSUS, Leidy.

Plate XX, Figures 4, 5; XXII, Figures 4, 5.

This is the characteristic true horse of the Equus bed of the western
parts of North America and of Mexico. It is represented in the Staked
Plain collection from Mr. Cummins by the following specimens: First,
two superior molars (one entire) and an inferior molar, found together
(No. 48); second, a nearly entire superior molar (No. 51); third, two in-

a

FAUNA OF THE EQUUS BEDS. 81

ferior molars with a fragment of lower jaw (No. 35); two inferior with
part of a superior molar (No. 39); molars lots 2, 4 and 49, and a sym-
physis mandibuli with incisors (No. 12).

The inferior molars display the characters already pointed out under
the head of the EH. simplicidens (page 66). They may be distinguished
from those of that species by the wide and deep channel of the internal
face of the crown, which is due to the wide divergence of the metaconid
from the metastylid; in this respect resembling the small species E. eurys-
tylus and #. minutus. The greater approach to isolation of the entostylid
also distinguishes them from those of EH. simplicidens.

Leidy united with this species his Hguus occidentalis*. In my synopsis
of the American species of this genus,{ I have retained them as distinct
on the ground of the smaller size of the protocone in the latter. It is,
however, the fact that the diameter of this column is frequently less on
the premolar than the molar teeth in this genus, although not always.
The types of Leidy’s description display this character in a marked de-
gree, and I have not observed it in the numerous specimens that have
come under my notice from the Staked Plains, while it is to be observed
in a majority of the teeth from the beds of the Oregon desert. Transi-
tions between the two types are not rare, and may be seen in passing
from the front to the back part of the full series in a skull described by
me from southwest Texas.{ See Plate XXII, Fig. 3.

The symphysis mandibuli repeats exactly the characters which I as-
signed to that of the EH. occidentalis in my paper above cited (page 11).
That is, the mental foramen issues entirely anterior to the posterior
border of the symphysis, and not entirely or partly posterior to it, as in
H. caballus. ‘The canine is separated from the external incisor by a
shorter symphysis than in the H#. caballus, resembling in this respect the
quagga. The symphysis is a little shorter in the Texas than in the
Oregon specimen.

A remarkable molar (No. 12, July 19), exhibits an unusual peculiarity.
The hypocone embraces posteriorly the enamel fold which separates it
from the metaconule, so that it becomes a columnar tube, and its section
on the grinding face an oval area. ‘The position is remarkable, being
immediately posterior to the internal half of the posterior lake, instead
of entirely interior to its internal margin, as is the usual position of the
inflection. This is probably due to the fact that this molar is the last one
of the series. In addition to this column there is a similar, but smaller,
one just posterior to the external bone of the posterior lake, which does
not extend so far posteriorly as the larger column already described.

*Report U.S. G. Survey Terrs., I, 1873, p. 242. Pl. XX XIII, Fig. 2.
+Proceeds. Amer. Philosoph. Soe., 1884, p. 10.

tAmerican Naturalist, 1891, p. 912.

_ 6—Geol

82 GEOLOGICAL SURVEY OF TEXAS.

The cutting off of this posterior loop so as to make it a circle in section
(a column) occurs frequently in the Protohippus placidus (Pl. XI, Fig.
5a); and Leidy figures a small circle in the Hquwus eacelsus (Ext. Mamm.
Dako. Nebr., Plate XXI, Fig. 31), but the presence of two such columns
is unprecedented in my experience.

I have already called attention to various characters in which this
species differs from H. caballus*. These are chiefly in the proportions
and details of the skull and limbs. I can not find any character of per-
manent value in the dentition; that mentioned by LeidyT, the absence of
the loop of the inner enamel border at the middle emargination, not
being constant. It is present in all the molars of the present collection,
and in the premolars of the skull from San Diego, Texas. The affini-
ties of the H. excelsus are nearer to the asinine division than to the
caballus division. While the molar teeth equal in dimensions those of
the HL. caballus, the bones of the limbs and feet are more slender. I find
the presence of a cuboid facet on the astragalus to be almost universal
in the #. excelsus, viz., in five astragali from Rock creek, Texas, and in
fifteen out of nineteen astragali from the Oregon desert. It is present
in the quagga in my collection, but is wanting in two horses in my
collection, while it is present in fourteen horses in the collection of the
veterinary school of the University of Pennsylvania, to which I have
had access through the courtesies of the authorities of that institution.

I give the following measurements of the metapodial bones of two
specimens, aS compared with those of the horse:

Meticarpus.
EH, caballus. E. excelsus HE. excelsus
Texas. Oregon.
Mm. Mm. Mm.
Length..... io nyayaleteital a) od Totsi7a: atpxolale Per ctieueks otete tertatiote 257 251 241
Proximal diameters. . anteroposerior ........ 44 32 40
transverse............. 68 ’ 53 60
Distal wae 2 2. o ws kletoeloraidiorele Sse eee oe 65 48 55
Meiatarsus.
TOTO CPA ayers eis ore loi ieiciciesa sine eyehe ee eR IT: 297 275 297
Proximal diameters. ; | anteroposterior eeecesee 52 48 50
transverse............. 67 51 , 60
DOTS bal WAC GHN efeia'e 0s: «seine aledsse'elorateastoee eee nttcis ss 59 50 57

The bones of the H. caballus belong to the same individual, while the
pertinence of the others to identical individuals is probable, but not certain.
The relatively greater robustness of the HZ. caballus is shown by the fig-

*Proceeds. Amer. Philos. Soc., 1884, p. 11.
+Extinct Mammalia Dakota and Nebr., 1869, p. 266.

}

FAUNA OF THE EQUUS BEDS. 83

ures; that is, the transverse diameters are relatively greater. A meta-
carpus and metatarsus of a second (and probably the same) individual,
from Oregon present the same characters. Both are rather larger in all
their dimensions than the corresponding bones from Rock creek. Such
variations, however, are not greater than those that occur in the Equus
caballus. ‘The phalanges are always relatively and absolutely smaller in
the #. eacelsus than in the average EH. caballus, as shown by a considera-
ble number of specimens.

The peculiarities of the basioccipital and exoccipital bones are constant
in my material (four individuals from Oregon), and the relatively shorter
diastema in front, and less pioduction posteriorly, of the maxillary bone,
are always observable. My only specimen with a full series of teeth
(Plate XXII, Figure 4), shows that the M. iii is considerably smaller than
in the true horse.

EQUUS MAJoR, Dekay.

This horse is represented in the Staked Plains collection by parts of
four superior molars found together (No. 11). They display the typical
characters of the species. I have already identified this species from
Wharton county, in Southern Texas,* and Leidy has reported fit from
various localities in the same State.

The relations of the species of Equus found in the Cenozoic beds of the
Staked Plains, as to horizon, size, and complexity of enamel folds, may
be represented as follows:

Equus bed. 4. eucelsus. EH. semiplicatus. H. tau. EH. major.
Blanco. E. simplicidens. EH. cumminsii. EH. minutus.
Goodnight’s. EH. ?simplicidens. E. eurystylus.

The lines of the above diagram indicate relationship, but we do not yet
know enough of the species to determine the phylogenies.

HOLOMENISCUS, Cope.

Proceeds. American Philosophical Society, 1884, p. 16.

HOLOMENISCUS HESTERNUS, Leidy.

Plate XXI, Figures 3, 4.

Cope, loc. cit., p. 17; Auchenia hesterna, Leidy. Report U. S. Geol.
Survey Terrs., I., 1873, p. 255, Plate XX XVII, Figures 1, 3.

A fine mandibular ramus containing all the molars, with the symphysis
containing all the incisors but one, was obtained by Mr. B. S. Brown from

*Proceeds. Amer. Philos. Soc., 1892, p. 123.
tReport U.S. Geol, Survey Terrs,, 1873.

84. GEOLOGICAL SURVEY OF TEXAS.

Austin county, in Southern Texas.* It is described under the head of
Pliauchenia spatula, antea, and is figured on Plate X XI, Figures 3, 4.
Mr. Cummins did not obtain it in Northwest Texas.

HOLOMENISCUS SULCATUS, Cope.

Sp. nov. Plate XXIII, Figure 4.

This large lama is represented by a mandibular ramus, from which the
condyle, coronoid process, angle and symphysis are wanting. The molar
teeth are all preserved. The length of the series of the latter is about
the same as in the HZ. hesternus, but the forms of the teeth are different.
The ramus is also much deeper in proportion to the other measurements.
The first premolar presents a grinding face of an elongate triangular
form, with the apex anterior and a little incurved. The true molars in-
crease rapidly posteriorly, the anteroposterior diameter of the first being
less than half that of the third. The inner wall of the true molar is not
flat as in the H. hesternus, but it is divided by an open groove opposite
the deeper internal groove, as in the species of Pliauchenia, thus dis-
tinctly marking off the anterior from the second column. In addition to
this there is an anterior and a posterior marginal internal rib on the second
molar, and an anterior marginal rib on the third. These do not exist in
the H. hesternus, but are present in the Pliauchenia spatula and the camel.
The camel possesses a keel on the internal side of the crown in the posi-
tion of the groove in the H. sulcatus.

Owing to the loss of the anterior part of the ramus, the character of the
canine tooth can not be ascertained. The first true molar is crowded by
the adjacent teeth, so that its internal wall overlaps the latter by a little.
This is probably an individual peculiarity.

The following comparative measurements show the relations of this
species with the H. hesternus:

*Mr. J. B. Walker makes the following note on the locality and occurrence
of this fossil:

‘* The locality should be Bowie Bend, Austin county. The fossil was found
by my assistant, Mr. B.S. Brown. * * * The bluff is in two terraces, and
the bones, when in place were in the upper part of the lower terrace, mixed
with the small siliceous pebbles, which are in moderate quantity at one locality
only, and this is where the river has made the greatest excavation, or in the
bend proper.”

It may be of interest in this connection to note the fact that this is the same
locality from which the fossils were obtained which were described by Dr. W.
M. Carpenter in American Journal of Science in 1846, p. 244, E. T. D,

. SS

FAUNA OF THE EQUUS BEDS. 85

Measurements.
H.sul- FH. hes-
catus. ternus,
Mm. Mm.
Tene thot molar series sii. ici te een dec cise cise see cee sence 146 157
Meno thiol true molars 2). ceicis daar essa eie cease Hawes sie ole 122 134
y i ETO DOSLEULOE Ge ai a- oc lat isle « o8eys « 25 35
Diameters M.i............ an
= oe EATS VOT S Onesie oho Gs rcs whee ble insilesesneleleiale 17 18
Ge teroposterior............. 2. cece 40 44
MEM saante aie? ao
iencette ; i GR AMSVENSOu geen eis we cid avicnan cieleiniale, oii 20 19
“ Hic UNGETOPOSLELLOL ejay cece aes evap e's 55 56
Dee Heda 1 transverse of middle column......... 20 18
Depth of ramus at M.i.......... 1. cece cee eee eet e ne cee 68 51
Depth of ramus at M. iii, middle column .....................-... 85 79

Numerous bones of camels of size and character appropriate to this spe-
cies were found by the expedition, but positive reference can not be made
at present.

HOLOMENISCUS MACROCEPHALUS, Cope .

Sp. nov. Plate XXIII, Figure 5.

This lama is determined from a nearly complete lower jaw. One ramus
is lacking in nearly all the parts posterior to the last molar, while in the
other these parts are present, lacking only the condyle and angular hook.
The dentition can be completely restored from one side or the other.

This species is ‘intermediate in dimensions between the LH. vitakerianus,
Cope, and the A. Jama, Linn, being smaller than the former in dental
measurements, and larger than the latter. The symphysis mandibuli has
about the length of that of the A. Jama, but the rami are considerably
more elongate, the extremity of the last molar in the A. Jama reaching
only to the middle of the anterior column of the corresponding tooth of
the H. macrocephalus. I observe here that it is not certain as yet that
the species now described is not an Auchenia, as the superior dentition is
not known.

The canine is separated from the third incisor by a diastema, which is
a little less than one-third the length of that which separates the canine
from the anterior premolar, and the latter is about equal to the dental
series, less the last molar. In its proportions to the other teeth the pre-
molar is much like those of the A. Jama, and is smaller than in the
vitakerianus. The disproportion in the sizes of the molars is not so great
as in the H. sulcatus. As in the latter species, the internal wall of each
molar is slightly concave at the point of junction of the columns, but in
the second and third true molars this concavity is bounded in front by a
narrow ridge, which is wanting in the H. sulcatus, and in the first true
molar of H. macrocephalus. A similar ridge exists at the front of the an-
terior column of the second and third true molars, as in A. lama. The

86 GEOLOGICAL SURVEY OF TEXAS.

first molar is injured at its anterior border, so that this point can not be
determined. The internal faces of the columns are but little convex on
M. ii and iii, but moresoin M. i. The anterior part of P. m. i. is straight,
as in the other species of the genus described in this report, and not in-
curved as in A. lama. The heel of the M. iii is more strongly incurved
than in the other species, and is more as in A. lama.

The canines are robust and are recurved, with a sharp posterior edge
and obtuse front at the base. The incisors are of graduated lengths, and
are entirely procumbent; the cutting edges of the second and third have
a strongly concave emargination of the border. Whether this is charac-
teristic of the species, I do not know, but the crown of I. iii is more ex-
panded outwards than in the H. hesternus and A. lama. The dental
foramen enters opposite the base of the keel of the M. iii, and it is not slit
downwards asin A. Jama. The mental foramen issues below the poste-
rior border of the canine, as in A. lama.

Measurements.

Mm.
MRotal lene thy of ramus) with AMCISOTS =e lo leet eteleielale lee lett eee ete rete ete 292
Length ofisymp by sis): !s Siete mists elsjorere ener ereiictess caloe eee oe eiehalet rsa eee 69
Elevation of precondylar notch above inferior border................-..-- 118
Lene thiok ramus posterior tose aillese iy -eielepeyes eleuseiels sis emia teetbee ieee 72
Depthiol ramusjat ono idiastennaie rive terlertetlallelelsiatele ries eee cei raietlale 22
DepthioL WAMUs| ate aM vesye\ccietetepeteeetel teat terelelo teste eielelerstieaas esr nese nn eneees 33
Depth'of ramustat hieelof: Micmiitioeneyee ma excecetortoue or ecercesiane we icierenele sntoravs tetera evs 51
Length of crown of I.i............ AWONGHOODE DS DEON OO HOGS adondooO nad os ioc 14
IOalean ooh oigal Ort WV Gao dobanaboe sonoKd ood04d pooadananpoooneodd dans 20
eng thot icrowmiofelis its. ee eee cers ee reise eetteeyeiael: We
NAMA Helton ik Cortona’ OWNER ThA 5 poddo5 Codann sooobo0 ab ad00dsun00000 HOO500 SHoda5 9
Length of. idental (series: .\. 22 sens cyeietorretsracheteieketsisia lets pevveleverevacsiae elaeteroicictrerale's 93
IVORY Ohi areTAC RTI Oi 12 als Hs Ge an cagecbo cco docdos conden panQoK OBO deE 14
Lene throb erinding Tacelot Meet Seytemtateteisteleratere tetera ete (elayelelat< aieteterell ore Sacpese 20
JEM Che rim avehtayes VENOM IES Ti. S56 odec dando sbo50sedGoh09050c0ndan00S > 24
Width of crown of P. m.i., posteriorly...................0. p Anions condos 5
Width of crown of M.i., posteriorly sic... ee.ce .. ees. e le nose ces +o vesicle 13 |
Width of crown of M. ii., posteriorly .............ceece cence een see veeeee 13

In the A. vitakeriana we have the following measurements of the su-
perior molars; the inferior molars are unknown. Length of molar series
without M. iii., 69 mm.; length of base of P. m. i., 20 mm.; length of
grinding face of M. i., 24 mm. As the length of the grinding face of
the P. m. i. exceeds that of the base, it can not be much shorter than that
of the M. i., so that the aggregate length of the two is at least 45 mm.
In the present species this dimension is 34 mm.

The Holomeniscus macrocephalus approaches more closely the existing
lama than any other extinct species of North America.

Rock Creek, near Tule Canyon; W. F. Cummins.

‘

—

FAUNA OF THE EQUUS BEDS. 87

SUMMARY OF SPECIES OF THE EQUUS BEDS OF THE STAKED

PLAINS.
TESTUDINATA.
Testudo hexagonata, Cope.
Testudo laticaudata, Cope.
EDENTATA.
Mylodon ?sodalis, Cope.
PROBOSCIDIA.
Hlephas primigenius, Blum.
DIPLARTHRA.

Equus eacelsus, Leidy.

Equus semiplicatus, Cope.

Equus tau, Owen.

Equus major, Dekay.
Holomeniscus sulcatus, Cope.
Holomeniscus macrocephalus, Cope.

PLATE 1.

FRAGMENTS OF BELODON SUPERCILIOSUS, COPE, ONE-HALF NATURAL SIZE, .
EXCEPT FIGURES 2, 3. i
Figurel. Left frontal bone with postfrontal and parietal. lacking poster ‘
portion, from above; a, same, fractured surface, posterior view.
Figure 2. Anterior tooth, natural size, from edge; a, from inside.
Figure 3. Groved tooth, natural size, from edge; a, from outside.
Figure 4. Anterior parts of splenial bones from below.
Figure 5. Portion of femur, external side. ;
Figure 6. Supposed fibula; a, distal fractured extremity; >, proximal « r
extremity.
Figure 7. Dermal bone from above; @, same, from behind.
Figures 8, 9,10. Dermal bones; 8 fractured.

[92]

BELODON SUPERCILIOSUS,

PLATE II.
TEETH OF TRIASSIC SAURIANS, NATURAL SIZE.

Figure1. Palewoctonus orthodon,Cope. Crown of anterior tooth, interior side;
a and b, edge views; c, section at inferior extremity of long cutting edge.

Figure 2. Paleoctonus appalachianus, Cope. Anterior tooth; lettering as in
figure 1.

Figure 3. Palcoctonus appalachianus, Cope. Posterior tooth, external, side; a,
internal side.

Figures 4-6. Palwoctonus dumblianus, Cope. Anterior and posterior teeth;
lettering as in figures 1-3.

[94]

TRIAS. Pare II.

1, PAL@OCTONUS ORTHODON. 2-3. P. APPALACHIANUS. 4-6, P, DUMBLIANUS.

PLATE Ill.

LOUP FORK EPOCH.

Figure 1. Portion of skull of Protohippus pachyops, Cope, type; left s
half natural size. ae a
Figure 2. Tetrabelodon serridens cimarronis, Cope; last inferior t

left side, one-half natural size, from above.
Figure 3. Same as figure 2, from inner side.

“SINOUUVNIO NOGOTAIVULAL *§-~Z “SdOAHOVd SOddiHOLOUd *T

Zy aes
Z| Wy yi
ZY, SY

Zh?

‘Ill f2vId “MAOH dNOT ~

Wit
ha’

PLATE IV.

LOUP FORK EPOCH.

Protohippus pachyops, Cope; colt skull, one-half natural size. a
Figure1. Left side. erinest tg
Figure 2. Inferior aspect. — : 4
Figure 3. Posterior view.

‘Se
,
[98 J :

“SdOAHOVd SOddIMOLOUd ¢

i Vaal f
Nay

Za

y x3
Ai
Wit a, 4

pont,

iF :

ANNs

“
Nh

"AI ALVId “MMOA dAO0'L

PLATE V.

LOUP FORK EPOCH.

Figure1, Protohippus fossulatus, Cope; skull of typical spec

one-half natural size. SAR

-

Figure 2. Five molars of right side of the same skull from below natu

ral s

HOUPRSEORIG,. Pram Ve

PROTOHIPPUS FOSSULATUS.

PLATE VI.

Sect LOUP FORK EPOCH.

Protohippus fossulatus, Cope; fragment of skull figured in d
natural size, from above. be

Be : [102 ]

"SOLVYTASSOd SAOddIHOLOUd

‘TA WLVId “MHXOd dNOT

PLATE VII.
/) Wome wos seocu y) laa

Protohippus fossulatus, Cope; fragment of skull meueee in Plate Vi,
natural size, from below. ’ nd

“SOLVTASSON SAddIHOLOUI

WO WL 9m, >
MON. WEF Way

ee

Wy
Ww, Z

ie Z SE hi al ! Loy) >
aN
IN [iis NY :

dy Ny ENF
ee, ~Y % y WW
we GMM YF =

4
L ——, :

SS

4

Ss

TIA GLVId “MHOX dNOT

PLATE VIII.

ee LOUP FORK EPOCH.

Protohippus mirabilis, Leidy; skull, left side; one-half natural size. — of
el . 1s

i

[106 J

“SITIGAVUIN SOddIHOLOUd

ir

i oy, XN
we Gy,
“YD

Ze

Tee

Yl?

WIA StvId “MHOX dNOT

PLATE IX.

LOUP FORK BPOCcH. BP i teva

Grinding faces of Ble teeth, natural size.
Figure 1. Protohippus mirabilis, Leidy ; specimen figured on. Plate A
Figure 2. Protohippus pachiyops, Cope; specimen figured on Plate Vv,

rior meee c

in inet ee

“SdOAHOVd “d “8-Z ‘SITIAVUIN SAddIHOLOYd “T

at © ae .
a eK: ‘XI TiVId “MAO dl01

PLATH X.
LOUP FORK EPOCH. " y a

Molar teeth of species of Protohippus, natural size.

Figure 1. Temporary dentition of colt of Protohippus ?pachyops, Copes
skull figured in Plate XII.

Figure 2. Protohippus perditus, Leidy; an old deciduous and imo young
manent molars, external view (d4 should be at the lower side of
figure); a. grinding faces; from northeast Colorado.

Figure 3. Temporary molars of a species of Protohippus; from Wyoming.

Figure 4. Protohippus ?mirabilis Leidy; with dentition.

Figure 5. Protohippus medius, Cope; superior molars; from Gotan oa
Oregon.

[110]

PLATE X.

SEX

=

=S

==>

N
)
NY
h

IN

5. PROTOHIPPUS MEDIUS, PERMANENT DENTITION.

1—4. TEMPORARY DENTITION OF THREE-TOED HORSES.

PLATE XI.
a LOUP FORK EPOCH.

Pk Dentition of species of Protohippus, natural size.

‘s

Figure 1. Protohippus ?parvulus, Marsh; superior molars.

Figure 2. Protohippus ?parvulus, Marsh; part of lower jaw, from ab¢

Figures 3-8. Protohippus placidus, Leidy; lateral views, and a, grindi
of molars. rs

Figures 3-5. Less worn molars.

Figure 5. Last superior molar.

Figures 6-8. Molars presenting more wear.

ear [112] ty

“SNaIOVId SAOddIHOLOUd

“TX FLvId (ora)

a

stage se wear; 2a. posterior side of a 2.
Figures 3-4. Superior molar teeth of Hippidiwm interpolatum, copes
faces; 3a, posterior view of figure 3. a
Figures 5-6. Superior molar teeth of Hippidium aspectans, Cope;
faces; figure 6, last molar; 6a, same, anterior face of figure 6.
Figures 7-8. Hquus eurystylus, Cope; inferior molars of different indiv

grinding faces; ie Sa, interior faces; 7b, 8b, ee faces of TO yns f
ie

114]

PLATE XII.

1-2, PROTOHIPPUS LENTICULARIS. 38-4. HIPPIDIUM INTERPOLATUM.
5-6. H. ? SPECTANS. 7-8. EQUUS EURYSTYLUS.

PLATE XII
BLANCO EPOCH.

Figures 1-3. Megalonyx leptostomus, Cope; natural size; from Mc
= Figure 1. Fragments of palate from below, with supposed positi on
Figure 2. Last superior molar, from below; a. from side.
Figure 3. Occipital condyle from above.
Figure 4. Borophagus diversidens, Cope; fragment of left mand
external view; 2 from above; b, noe view.

ae behind; 6, from Som

PLATE XIII.

BLANCO.

-

on

Sa

Res SSS SS Se

> ———
n=

Seeee!

in moccceceseboss

4, BOROPHAGUS DIVERSIDENS,
5, PLATYGONUS BICALCARATUS,

1-3. MEGALONYX LEPTOSTOMUS.

PLATE XIV.
BLANCO EPOCH.

Figures1-1l. Felis hillanus, Cope; natural size.

Figure 1. Superior canine, internal side; a, external side; b, apical view.

Figure 2. Spine with postzygapophyses of lumbar vertebra from right side; a,
posterior view.

Figures 3, 4,5. The left second, third and fourth metacarpals, front views; a,
internal views; 0, external views; c, proximal extremities.

Figure 6. Trapezium, proximal extremity.

Figure 7. Unciform from front; a, proximal; 6, external, and c, distal views.

Figure 8. Calcaneum from above; a, distal view. ; ;

Figure 9. Second left metatarsal, front view; c, proximal extremity.

Figure 10. Phalange of first series from front; a, posterior; 0, proximal views.

Figure 11. Phalange of second series from front; a, posterior; 6, proximal, and
c, distal views.

Figures 12-14. Canimartes cumminsii, Cope; dentition, natural size.

Figure 12. Superior sectorial, external size; a, internal side.

Figure 13. P.m. iv and m. m.iand ii of superior dental series, from below.

Figure 14. P.m.iv and m. m. i and ii of inferior dental series, from outer side;
anterior half of P. m. iv wanting; a, internal view; b, from above.

[118 ]

_

- a*
2 >. 2 ieee ee +

— |.

BLANCO. PLATE XIV.

1-11. FELIS HILLANUS. 12-14. CANIMARTES CUMMINSII.

PLATE XV.
BLANCO EPOCH.

Figure 1. Tetrabelodon shepardii, Leidy; mandible from left side; one-half
natural size.
Figure 2. Same; right mandible as far as last molar, inclusive, from above.

| 120 |

PLATE XV.

x

TERTRABELODON SHEPARDII.

SR na ay Staats Sal AW
j i.

7 oe h S
, Sek. ae, ro .

i corny ee Se

The 2" aoe

a

SS

4G

Figure 3. Dibelodon humboldtit, Cuv.; first inferior molar of the nigh ic

PLATE XVI.
BLANCO EPOCH.

Figure 1. Dibelodon tropicus, Cope; part of mandible from
natural size; Ja, last molar tooth seen directly on upper
from inner side of ramus; same proportion.

Figure 2. Dibelodon humboldtii, Cuv.; ?
natural size.

last deciduous molar, ae
within; 3a, same from without; both natural size.

Figure 4. Dibelodon humboldtii, Cuv.; second superior true molar of

side, natural size, from below. Found separately.

[ 122 J

——>

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SS
S

S

AS

SA

SSN

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Up

LL,

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ey

WE:
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Yi,
tos
ty,
ty}
Li

Ji;
Z
Ls
Vy,
GG
GZ

2-4, D. HUMBOLDTII.

Prate XVI.

1. DIBELODON TROPICUS.

=

Fi

ZS

ae

PS SE pe eee

eo

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hte 8 1 ee APNE 7
Dann hel
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= 7
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ape
f ;
i | -
3 : :
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= - ;
-

PLATE XVII.
BLANCO EPOCH.

Figure 1. Dibelodon tropicus, Cope; left mandibular ramus from outside; one-
half natural size. ee
Figure 2. Dibelodon tropicus, Cope; first inferior true molar of left sidefrom __
above; 2a, same, inner side; both natural size. : ;
Figure 3. Dibelodon tropicus, Cope; first superior molar of left side from below; — Mages
natural size. “
Figure 4. Dibelodon humboldtii, Cuv.; first inferior molar of right side, figured
on Plate XVI, seen from above; natural size.

[ 124 J

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Ms.

ve

a

wn

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Ne

Nl
\ SAAS NG :
QS \\ \Y . Wa

SS

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s

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a
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,

4
7 = aE
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.

q 1-3. DIBELODON TROPICUS. 4. D. HUMBOLDT.
-

PLATE XVIII.

BLANCO EPOCH.

Dibelodon precursor, Cope : last inferior true molar of left side, from al ove

anterior cross-crest supplied; natural size. ‘ =

PLATE XVIII.

me tr an ae ee
seer R T Se

-_"\

Ts
’ ey

\

/ eam \ ' 1
i beredeceueL

4 a
ere &
ss. iY
. xe
es “se i
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‘ yt
4 . , t
. ‘ , H
\ Nor 2
Nae” 1
=
v2 ‘
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1G
AM,
4

a (

\

DZ

DIBELODON PRECURSOR.

_ PLATE XIX.

BLANCO EPOCH.

Dibelodon precursor, Cope; tooth figured in Plate XV.
side; naturalsize, = 2 Sea ag

PLATE XIX.

Sisanes
és.

=

~s
..
on
—
sae,
ee cay Me ee ya
Sot eat aC
Sama

an

L7ZZZZZZP
a ZEA
EF OAAZZAZZZED Z
ZZ LE EA
ES = = EEE,

Y Yi
SAE Sw
| Z STU ——
EEZUZZZLZZZZZ aS
z = =

\
\
\

NW

“7
<weo----"
<="
anoorn”
oe
oor"

DIBELODON PRZCURSOR.

PLATE XX.
TEETH OF EQUIDA OF THE BLANCO EPOCH, NATURAL SIZE.

Figure 1. Superior molar of Hyuus simplicidens, Cope; grinding face, from
below; a, lateral face.

Figure 2. Hquus simplicidens, Cope; inferior molars, grinding face, from above.

Figure 3. Hquus simplicidens, Cope; inferior m. ii. side view; from a different
individual from those figured in figures 1 and 2.

Figure 4. Equus occidentalis, Leidy ; two inferior molars from above; from Fos-
sil Lake, Oregon.

Figure 5. Equus occidentalis, Leidy; probably temporary inferior molar from
above; from Fossil Lake, Oregon.

Figure 6. Hquus eurystylus, Cope; inferior molar, grinding surface, the right
extremity too short, see plate; a, lateral view of same; from Paloduro
Canyon.

Figure 7. ZHquus cwmminsti, Cope; left superior molar.

Figure 8. Hquus minutus, Cope; inferior molar, grinding face; a, internal; 0,
external views.

Figure 9. Hgwus sp.; part of right superior molar, from Paloduro Canyon.

[130 ]

“SOTALSAUNA A “9 “SITVINACGIONO “A “¢-f “SNACIOLIdWIS SONO" *g-T

“TISNIWNWOO “H *)

“SOLONIM “A *g

nw nmeworwesw a, a

oe-= Thy

© egeassesrzs,

ese

‘XX SivId “OONV1TE

Ce ee i ES.

PLATE XXI.
MANDIBLES OF CAMELS, ONE-HALF NATURAL SIZE.

Figurel. Pliauchenia spatula, Cope; left mandibular ramus, externa
Mont Blanco. # ne
Figure 2. Same, from above. oe
Figure 3. Holomeniscus hesternus, Leidy ; left ramus mandibuli, extern
Austin county. .
Figure 4. Same, from above:

[ 132]

BLANCO. EQUUS BED. Prats XXI.

YN
y

Z
ty
Ly J J

1-2, PLIAUCHENIA SPATULA. 3-4, HOLOMENISCUS HESTERNUS.

PLATE XXII.
EQUUS BED.

cua Testudo his ames Cope; rie of plastron, a Sn natural

Figure 2. ea ee Cope; plastron from below; wae natural
size. ei
Figure 3. Hguwus excelsus, Leidy; right half of inferior surface of cranium an-
terior to glenoid facet, seen from below; one-half natural size. From ,
specimen from San Diego, Texas, from W. Taylor, in collection of EH. D. a
Cope. Oe ;
Figure 4. Hquwus excelsus, Leidy; right superior molar, little worn grinding
face; natural size. 4
Figure 5. Equus excelsus, Leidy; right inferior molar, of probably the same —
individual as that represented in figure 4; both from the Equus beds of
Rock Creek; 5a, same tooth from inner side; all natural size. é

[134] Ss 4

=
=
4
A
il
a
=|
S|
Ay

es

\

\ seca

| an \
\ |i ms ( |
oN

(ZB I eu8 at
x - |

A

ie

2. T. HEXAGONATA. 3-5. EQUUS OCCIDENTALIS.

1. TESTUDO LATICAUDATA.

PLATE XXIII.
EQUUS BED.

Fgure 1. Zquus cumminsii, Cope; external part of superior molar, showing
lakes; from the Blanco bed at Mont Blanco; natural size.

Figures 2-3. Equus semiplicatus, Cope; superior molars, grinding faces; natural
size; from the Equus bed of Rock Creek.

Figure 4. Holomeniscus sulcatus, Cope; part of left mandibular ramus support-
ing all the molar teeth; one-half natural size; a, molar teeth from above;
from the Equus bed of Rock Creek.

Figure 5. Holomeniscus macrocephalus, Cope; right side of mandible; one-half
natural size; a, the same, with symphysis viewed from above. —

[136]

|

PLATE XXIII.

fs
‘ida

|

* 1. EQUUS CUMMINSII. 2-3. E. SEMIPLICATSS. 4, HOLOM®NISCUS SULCATUS. 5. H. MACROCEPHALUS.