2. VERTEBRATE FAUNAS OF THE OJO ALAMO, KIRTLAND, AND FRUITLAND 

FORMATIONS. 

By CHARLES w. GILMORE. 

INTRODUCTION. 

The presence of dinosaurian fossil remains 

near Ojo Alamo, in the northwestern part of 

the San Juan Basin, N.Mex., was first reported 

by George Pepper, of the Hyde Exploring Expedition, in 1902. Dinosaurian fossils from the 

San Juan Basin were known, however, as early 

as 1885. Cope 1 identified, in collections made 

by David Baldwin, teeth pertaining to the 

genera Dysganus, Loolaps, and Dielonius. None 

of these are now recognized as valid genera. In 

1904 Barnum Brown, of the American Museum 

of Natural History, New York, made a short 

reconnaissance trip into this region and procured a small but interesting collection of vertebrate fossils, including specimens that were 

later made the types of Kritosaurus navajovius 

Brown, Thescelus rapiens Hay, Aspideretesfontanus Hay, A. vorax Hay, and A. austerus Hay. 

In 1908 James H. Gardner, while engaged in 

field work for the United States Geological Survey, made a small collection of fragmentary 

vertebrate remains, and the next summer, 1909, 

accompanied by J. W. Gidley, of the United 

States National Museum, he obtained a second 

small collection. Two of the turtle specimens 

collected by Mr. Gardner were selected by 0. P. 

Hay as the types of the species Adocus vigoratus 

Hay and Basilemys nobilis Hay. 

In 1912 Walter Granger and W. J. Sinclair 

visited this region and as an incidental part of 

their work in the overlying Puerco and Torrejon deposits made a small collection of reptilian 

fossils from the Ojo Alamo sandstone, in which 

a second specimen of Kritosaurus navajovius 

was recognized and bones of 11onoclonius and 

Deinodon were noted for the first time. 

During the field season of 1915 a party under 

the leadership of C. Max Bauer, assisted by 

J. B. Reeside, jr., made the most extensive and 

best collection of fossil vertebrate remains yet 

procured from this area. 

I Cope, E. D., The relations of the Puerco and Laramie deposits: Am. 

Naturalist, vol. 19, pp. 985-986, 1885. 

In the present paper I have brought together 

all the information obtainable relating to the 

extinct vertebrate fauna of the Ojo Alamo 

sandstone and of the deposits that immediatelv 

underlie that formation. A considerable nu~­

ber of genera and species have now been described in widely scattered publications, and 

these descriptions are here compiled as an aid 

to future students. 

0. P . . Hay and Barnum Brown have been the 

chief contributors to our knowledge of this 

fauna, and I have made free use of their articles. The original descriptions of such genera 

or species as have been established on specimens from these deposits are given in full, followed by such comments and emendations as 

more recent discoveries and additional rna terial 

render possible. 

I wish here to acknowledge my indebtedness 

to Dr. L. M. Lambe, of the Geological Survey 

of Canada, and Dr. W. D. Matthew, of the 

American Museum of Natural History, New 

York, for furnishing me with excellent photographs of the skulls of Gryposaurus and Kritosaurus, here reproduced; and to Mr. Barnum 

Brown, also of tlie American Museum of N atu-· 

ral History, for valuable assistance in identifying specimens. 

THE VERTEBRATE FAUNA. 

The known vertebrate fauna of the dinosaurbearing beds in the San Juan Basin in northern 

New 11exico consists of a considerable number 

of genera and species, but many of them have 

been identified from material so insufficient and 

fragmentary that it is quite impossible to define 

them properly. A few, however, are fairly 

diagnostic, so that comparison with related 

forms of other geologic formations serves to 

give some clue as to the age of the deposits 

from which these specimens were obtained. 

In the preceding paper of this series Mr. 

Bauer has subdivided the dinosaur-bearing 

deposits into three formations-(1) the upper279 
280 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

most, or Ojo Alamo, as named by Brown/ now 

restricted to include only the upper sandstone, 

conglomerates, and interbedded shale lenses, 

(2) the Kirtland, and (3) the Fruitland. Vertebrate fossils are found throughout these deposits, though they appear to occur most abundantly in the Ojo Alamo and the upper part of 

the Kirtland, sparsely in and below the Farmington sandstone member of the Kirtland, and 

more abundantly in the Fruitland. 

Material is not yet available for determining 

whether these formations can be said to carry 

distinctive vertebrate faunas. The faunas as 

now known are as follows: 

Ojo Alamo sandstone: 

Dinosauria: 

Kritosaurus navajovius Brown. 

Monoclonius sp. 

Deinodon? 

Chelonia: 

Basilemys nobilis Hay. 

Adocus? vigoratus Hay. 

Aspideretes vorax Hay. 

Aspideretes fontanus Hay. 

Aspider~tes austerus Hay. 

Thescelus rapiens Hay. 

Compsemys sp. 

Crocodilia: 

Crocodiles. 

Pisces: 

Lepisosteus sp. 

Kirtland shale: 

Dinosauria: 

Kritosaurus navajovius Brown. 

Carnivorous dinosaurs. 

Ceratopsian dinosaurs. 

Armored dinosaur (Ankylosauridre). 

Chelonia: 

Baena nodosa n. sp. 

N eurankylus baueri n. sp. 

Aspideretes sp. 

Adocus sp. 

Plastomenus sp. 

Crocodilia: 

Crocodiles. 

Brachachampsa sp. 

Pisces: 

Lepisosteus sp. 

Myledaphus sp. 

Fruitland formation: 

Dinosauria: 

Monocloni us? 

Carnivorous dinosaurs. 

Chelonia: 

Adocus? lineolatus Cope. 

Aspideretes austerus Hay. 

Pisces: 

Lepisosteus sp. 

1 Brown, Barnum, The Cretaceous Ojo Alamo beds of New Mexico 

with description of the new dinosaur genus Kritosaurus: Am. Mus. Nat: 

Hist. Bull., vol. 28, pp. 267-268, 1910. 

No mammal, bird, or amphibian remains 

have yet been recorded from these formations. 

The fishes are represented by two genera, Lepisosteus and Myledaphus, neither of which have 

any value in correlation. The same may be said 

of the Crocodilia. The Chelonia are the best 

rep res en ted, nine genera and eight species ha ving been recognized, and systematic collecting 

would doubtless add several more. Unfortunately, more than half of the described species 

have been founded upon fragmentary material, 

and it is with difficulty that they are compared 

with better-preserved specimens of other geologic horizons. With the exception of .Adocus? 

lineolatus Cope all the recognized species have 

been based on specimens collected from these 

formations, so that they offer but little aid in 

correlation. The discovery in the . Kirtland 

shale of the genus N eurankylus is significant, 

as previously it has been known by a single 

specimen from the Belly Riverformation. Basilemys nobilis Hay, from the Ojo Alamo, has 

its closest affinities in an undescribed specimen 

from the Two ~1edicine formation, of Montana, 

a formation that is in part equivalent to the 

Judith River. According to Hay, Thescelus 

rapiens appears to approach Thescelus insiliens 

from the lower Lance, but Baena nodosa offers 

no close comparisons. 

The dinosaurs were apparently the predominating vertebrates of these times, and they 

afford the best basis for a comparison with forms 

found elsewhere. The Trachodontidre and Ceratopsidre give the most information relative to 

the age of these deposits. The finding of the 

genus Kritosaurus, known elsewhere only from 

the Belly River; the presence of trachodont 

teeth with papillate borders, a condition heretofore found only in forms from the Niobrara, 

Judith River, Belly River, Two Medicine, and 

Edmonton formations; and the finding of maxillre having 42 rows of teeth, whereas none of 

the known specimens from the Lance formation 

have less than 52 vertical rows, all constitute a 

combination of evidence showing a greater antiquity than Lance time for the beds from which 

these specimens were obtained. 

The Ceratopsia give corroborative evidence 

of this conclusion, as shown by specimens found 

in the Ojo Alamo and Fruitland formations 

which are provisionally identified as pertaining 

to the genus Monoclonius. Regardless of the 

uncertainty of the generic designation of these 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 281 

specimens, they unquestionably represent the formations show beyond all q[es~i~n that they 

so-called primitive ceratopsians; none of which pertain to a fauna or fauna distinctly older 

are found in beds younger than the Edmonton. than that of the Lance, and t. at such evidence 

Brown 1 has recently said, in regard to the as there is contributes to the s1pport of Brown:s 

age of the Ojo Alamo formation: contention that the Ojo Alamo sandstone Is 

The vertebrate fauna is distinctly older than that of synchronous with the Judith IRiver and Belly 

the Lance. I have expressed the opinion that it was com- River formations as found in areas to the north. 

parable to the Edmonton, but from the recent discovery I 

of Kritosaurus in the Belly River formation and the primi- Class REPTILIA

1 tive structure of the contemporary dinosaurs the Ojo Alamo Order DINOSAURJA. 

beds appear to be synchronous with the Judith (Belly I 

River) formation. That the deposits in the ~an Juan Basin 

contain a rich dinosaurian ~anna is clearly These conclusions were based by Brown on ind. icated by the discovery 0 numerous £ragspecimens collected in the upper 200 feet of mentary remains at many localities. In the 

deposits that immediately underlie the Puerco, ·collection made by Mr. Bau r in 1915 speciand it is quite likely that son1e of these forms mens sufficiently perfect to lbe identified as 

came from beds now included in the Kirtland dinosaurian were found in 0 less than 35 

shale. However that may be, Brown has now localities and at several f.orizons. These 

established the geologic position of the type of specimens consist chiefly of llimb bones, verKritosaurus navajovius as below the lower con- tebne, skull fragments, an~detached t. eeth. 

glomerate and therefore in the Kirtland shale, The greater number of the were chalcedobut the subsequent discovery of a second speci- nized, a condition common i the Two Medimen of the same species above the lower con- cine formation of northwestern Montana and, 

glomerate shows that the basis for his original as Brown 2 has pointed out, also "in the 

contention is not altered by this later subdivi- Judith River, but never o~served in the 

sion of the deposits. In the Bauer collection Laramie." (By "Laramie" I I take it he 

of 1915 was a ceratopsian ischium from the Ojo means the Lance.) Only two of the three 

Alamo sandstone identified as pertaining to suborders into which the Dinpsauria are subMonoclonius, a Judith River and Belly River divided have yet been recognized. The Pregenus. This occurrence and the presence in dentata are represented by ltrachodont and 

the same formation of the turtle Basilemys ceratopsian remains, and thJ Theropoda, or 

nobilis Hay, which has its closest affinities with flesh-eating dinosaurs, by nuferous detached 

a Two Medicine form, both support Brown's teeth and fragmentary bones. I Specimens repcontention. resenting the Ornithopoda, of "bird-footed." 

Although much is needed in the way of better dinosaurs, have not yet beer found, but 1t 

material before it will be possible to determine may be confidentl~ expected tha~ larger co!-

even approximately the vertebrate faunas of the lections will contain representatives of thiS 

Ojo Alamo and underlying formations, enough group also. + 

is already known to indicate their diversity. 

The discovery of two new species of turtle, Suborder PREDENT A. 

Neurankylus baueri and Baena nodosa, seems Family TRACHODONTil>lE Marsh. 

to indicate that a careful and systematic search Kritosaurus navajovius Brown. of these areas for vertebrate remains would be Plate LXXII, A; Plate LXXIII! figures 3 and 5. 

well rewarded. Kritosaurus ~ N H. B 11 navajovius Brown, Am. us. at. 1st. u ., 

Mter a study of the material in the United vol. 28, pp. 269-274, pis. 28, 29

1 

text figs. 2-7, 1910. 

States National Museum collections from this Sincla.ir and Granger, Am. Mus. f at. Hist. Bull., vol. 

area, and after reviewing the literature in which 33, pp. 301, 303, 1914. 

specimens from these formations have been de- Brown, Geol. Soc. America Bull., vol. 25, p. 380, 1914. 

scribed, I conclude that the vertebrate remains The present genus a~d spec 1es were founded 

from the Ojo Alamo, Kirtland, and Fruitland upon a weathered skull, lower jrws, and atlas, of 

1 Brown, Barnum, Cretaceous-Eocene correlation in New Mexico, 2 Brown, Barnum, The Cretaceous Ojo Ala o beds of New Mexico, 

Wyoming, Montana, and Alberta: Geol. Soc. America Bull., vol. 25, wi~h description of the new dinosaur genus Kr tosaurus: Am. Mus. Nat. 

p. 380, 1914. H1st. Bull., vol. 28, p. 268, 1910. 1 
282 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

which the skull and jaws are•shown in Plates 

LXXII, A, and LXXIII, fi'gure 5. It was described by Brown as follows: 

Type of species, No. 5799, American Museum collection. 

Generic characters.-Skull deep; muzzle narrow; frontals 

short, orbital portion reduced, barely coming to the border 

of the orbit; nasals and premaxillaries very long, quadrate elongate; quadratojugal short anteroposteriorly, completely separating quadrate and quadratojugal. Mandibular rami massive; edentulous portion decurved. Teeth 

spatulate in lower jaw. 

Specific characters.-Maxillary teeth smooth on borders. 

Mandibular teeth papillate on borders, median carina low, 

predentary deep and massive. Free edentulous portion 

of dentary not covered by predentary, short. 

The skull is that of an old individual, and most of the 

sutures are obliterated by exfoliation. When found it 

was almost completely weathered out and the anterior 

end was in a very fragmentary condition. It was impossible to place many of these fragments in the restoration 

and where there was no contact the bones were left out. 

The dentary and predentary were perfectly preserved, 

thus determining the length of the skull. The nasals were 

restored after the skull of Trachodon (Diclonius) Cope, and 

the premaxillaries according to the relative size between 

the predentary and premaxillary in that species, which 

necessarily made the rostrum much deeper. 

SKULL. 

The skull is very deep and more massive than in any 

heretofore-described species of the family, and its elements 

in general follow the Trachodon form, but with the following distinct modifications: Premaxillaries and rostrum 

proportionately shorter. than in Trachodon (Diclonius) mirabilis or Claosaurus annectens Marsh. Frontal short 

anteroposteriorly, prefrontal and postfrontal almost excluding it from the border of the orbit. Paroccipital 

process of exoccipital actually and relatively longer than 

in Trachodon. Orbital opening proportionately smaller 

and laterotemporal fenestra proportionately larger than in 

Trachodon. Quadrate and jugal completely separated by 

quadratojugal, the exposed part of which is short anteroposteriorly and vertically high. Ectop'terygoid extending forward to the union of the maxillary and the jugal. 

LOWER JAW. 

The lower jaw in form resembles more closely Judith 

River than Laramie [Lance] species. Its edentulous portion not covered by predentary is shorter than in any 

Laramie [Lance] form. 

Predentary.-The two predentaries are firmly coossified, 

forming a 8ingle element, but clearly show their union in 

the median line. Its lateral borders are massive and 

nearly vertical, forming a powerful clipping instrument, 

whereas in all Laramie [Lance] forms they are delicate 

and conform to the shape of the rostral bones. The 

anterior upper border is very rugose and is perforated by 

two parallel series of vascular foramina, resembling alveoli, but which pass obliquely downward and open on the 

outer surface. Each arm of the n terminates in a short 

rounded inner and a longer outer process. On the posterior lower border in the center there are two processes, 

an inner short, free tonguelike process which separates 

the upper anterior ends of the dentaries and a longer, 

wider process which underlies the symphysis. The latter 

process is broken near its origin and shows no indication 

of bifurcation. 

Dentary.-This element is very massive. The edentu"' 

lous portion is about one-fourth of its entire length, is ' 

strongly decurved, and near the symphysis curves inward. 

The coronoid process rises opposite the last row of teeth, 

as in the genus Trachodon, but the backward prolongation 

of the surangular gives it the appearance of being further 

forward. It is intermediate in position, in relation to the 

complete mandible, between Trachodon and the European genus Hecatasaurus.1 

Surangular.-The surangular is proportionately longer 

than in Trachodon. Its anterior vertical process is truncated obliquely and expanded to continue · the posterior 

lower border of the coronoid process. Posteriorly it 

broadens and furnishes four-fifths of the articular surface 

for the quadrate. 

Articular.-The articular forms the extreme end of the 

jaw and is wedged in between the posterior ends of the 

surangular, angular, and splenial. It furnishes about 

one-fifth of the articular surface for the quadrate, in front of 

which it contracts to a thin wedge but does not reach 

forward to the end of the dentary process. 

Splenial.-The splenial follows the usual Trachodon 

form. 

Angular.-The angular is very long and narrow. Posteriorly its lower border is visible on the outside of the jaw. 

Anteriorly it forms the lower border of the Meckelian 

groove and extends neariy to the middle of the dentary. 

TEETH. 

Two distinct types of teeth appear in the family Trachodontidre. In the earliest representatives known, Claosaurus agilis Marsh, from the Niobrara, and species from 

the Judith River beds that have been referred to Trachodon, the enamel face of mandibular teeth is spatulate in 

form and papillate on the borders. In the larger Laramie 

[Lance] Cretaceous species the enamel face of the mandibular teeth is diamond-shaped, with smooth borders. 

The teeth of K. navajovius are of the primitive form. [See 

Pl. LXXIII, fig. 3.] Both upper and lower series, respectively, are larger than in any described species of the 

family. In the mandibular series there are 42 vertical 

rows of teeth. On the triturating surface one tooth, enamel bearing, a half-worn tooth, and an indefinite number 

of worn roots appear in each row. The enamel face of each 

tooth is spatulate and rather sharply pointed at the summit; median carina low; lateral surface flat; borders not 

raised above the flat surface and sparsely studded with 

enamel papillre that apparently lack definite arrangement. 

In the maxillary series there are 4 7 vertical rows, and 

never more than two enamel-bearing teeth appear on the 

triturating surface in each row. They are smooth on the 

borders and very strongly curved transversely; median 

carina very high. 

1 To replace Limnosaurus Nopcsa, 1900; preoccupied by Limnosaurus 

ziphodon Marsh, 1871, Acad. Nat. Sci. Philadelphia Proc., vol. 23, p. 104. 

Type; Limnosaurus transsylvanicus Nopcsa, Akad. Wien Denkschr., 

vol. 68, pp. 555-591, 1900: 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 283 

MEASUREMENTS. 

Skull. Millimeters. 

Length, as restored. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 995 

Width across frontal above orbits....... . . . . . . . . . . . . . 220 

Width across proximal ends of quadrate. . . . . . . . . . . . . 350 

Width across distal ends of quadrate. . . . . . . . . . . . . . . . 490 

Frontal, length anteroposteriorly..... . . . . . . . . . . . . . . . 198 

Parietal, length ................ . ........ . . . ... . ... 113 

Supratemporal vacuity, length .......... ... ........ . 140 

Supratemporal vacuity, width ..... . .. . ......... . ... 100 

Quadrate, height. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516 

Quadratojugal, exposed, length anteroposteriorly. . . . . 42 

Quadratojugal, exposed height.. ... . . . . . . . . . . . . . . . . . 160 

Ectopterygoid, length ........ . ..... . .............. . 190 

Lower jaw. 

Length without predentary .. . ... . ... . ...... . ...... . 

Predentary, length .......... ...................... . 

Angular, length ........ .. . . . . . .. .................. . 

Splenial, length . ......... . ... . .... . ............... . 

775 

240 

250 

260 

proves to be a synon 

described Kritosaurus. 

of the earlier 

As has been pointed out y Brown, the discovery of Kritosaurus in the Kirtland and Ojo 

Alamo beds has an importa t bearing on the 

relative age of these formations and would appear to indicate t. hat they ar1

1 synchronous with 

the Judith River formation. 

Articular, length ............. .. . . . . . ... ........... . 

In his original paper Brown failed to state 

the geologic level where the {ype specimen was 

found, but in a letter to me dated February 

26, 1916, he says: "Kritdsaurus navajovius 

came from the upper part of r hat is designated 

by Bauer as the Kirtland formation." At the 

time he wrote the original escription of this 

dinosaur Brown considere1 the Ojo Alamo 

formation as extending downward at least 200 

feet below the . Puerco-Tort ejon contact, so 

95 ml( !f;::u::i:::: ·~:: : t:::::~: Teeth. 

Dental series, upper jaw, length ....... . ... . ........ . 410 

Tooth, mid-section, lower jaw, length.. . ........... . 45 

Tooth, mid-section, lower jaw, width.. .. . . . . . . . . . . . 15 

Four years later Lambe 1 described the new 

genus and species Gryposaurus notabilis, from 

the Belly River formation of Canada, based on 

a beautifully preserved skull (see Pl. LXXII, 

B), with which was associated a considerable 

part of the skeleton, including some areas of 

skin impressions. In a report made to Sinclair 

and Granger and included in their paper on the 

Paleocene deposits of the San Juan Basin 2 Brown 

calls attention to the description of Gryposaurus 

notabilis Lambe, and remarks: "In all respects, 

including the remarkable development of the 

nasals, premaxillaries, and predentary and reduction of the orbital portion of the frontal, 

this skull agrees with the type of Kritosaurus, 

and there is no doubt of their identity." 

In this conclusion Brown is undoubtedly 

correct, but in justice to Lambe it should be explained that, although Brown had one of the 

characteristic nasal bones, it was not inserted 

in the restored skull as figured by him (see Pl. 

LXXII, A), because tpere was no contact with 

contiguous parts, and the absence of this portion undoubtedly led Lambe into the unfortunate error of establishing a genus which now 

I Lambe, L. M., On Gryposaurus notabilis, a new genus and species 

oftrachodont dinosaur from the Belly River formation of Alberta, with 

a description of the skull of Chasmosaurus belli: Ottawa Naturalist, 

vol. 27, pp. 145-149, pl. 18, February, 1914. 

2 Am. Mus. Nat. Hist. Bull., vol. 33, pp. 297-316, June, 1914. 

30830°--17----19 

the Kirtland shale, a trac wdont maxillary, 

with fragments of the skull~ ~ collected by Sinclair and Granger "a few fe t above the conglomerate separating the two1 horizons at which 

dinosaur bones were found,'' pas been identified. 

by Brown as pertaining to I.Kritosaurus navajovius, thus demonstrating he occurrence of 

this genus and species in th~ Ojo Alamo sandstone, as now defined by Bal!ler. 

In addition to the papill te borders of the 

mandibular teeth, which indfcate a greater antiquity than Lance for Kritosaurus, the smaller 

number of vertical rows in the dental magazines also points to the same conclusion. 

Lambe 3 from excellent m terial defines the 

genus as follows: 

Skull large, narrow, and very de · p, with highly arched 

nasals. The lower anterior border I of the premaxillre expanded laterally. Orbit much snialler than the lateral 

temporal fossa. Quadrate high, rtially separated from 

the jugal by a small quadratoju~l. Mandible robust. 

Predentary expanded laterally and l eflected in the hinder 

half, and posteriorly bifurcated elow at the midline. 

Neural spines of the anterior dorsal vertebrre long. Ischia 

not expanded distally. Body covejred with small, polygonal, nonimbricating, tuberculate scales of rather uniform size. 

In figure 28 is shown a a teral view of an 

anterior dorsal vertebra of ~ large trachodont 

dinosaur, provisionally iden~i ed as pertaining 

to the genus Kritosaurus. The great height 

a Op. cit., pp. 145- 46. 
284 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

of the neural spine, the relatively small size of 

the centrum, the weakness of the neural arch, 

with broad, oval neural canal, and the anterior zygapophyses close together and lower 

than the posterior zygapophyses, are all features in close accord with the anterior dorsals 

of the type specimen of Hypacrosaurus, from 

the Edmonton and Two Medicine formations. 

The above-stated combination of characters 

at once distinguishes this vertebra from all 

known Lance trachodonts, but as both Lambe 

FIGURE 28.-Anteric.~· dorsal vertebra of Kritosaurus? sp., No. 8354, 

U. S. N. M:. About one-fourth natural size. 

and Brown have described Kritosaurus as 

having tall spines on the anterior dorsals, it 

.can with greater propriety be referred to that 

genus until such time as the discovery of undoubted remains of Hypacr<;>saurus show its 

presence in the Kirtland shale. 

The only important character wherein this 

vertebra differs from the type of Hypacrosaurus is the lack of an opening in the thin plate 

which descends from a point between the posterior zygapophyses to the upper median border of the neural canal. This vertebra was 

associated with a number of dorsal and caudal 

vertebral centra,·a scapula (see Pl. LXXIII, fig. 

2), the proximal half of a femur, portions of 

two ribs, and fragmentary portions of other 

bones. A small trachodont femur in this same 

lot shows that more than one individual is 

represented by this collection, so it can not be 

positively asserted that all the bones enumerated above pertain to a single individual. 

These bones were collected by Messrs. Bauer 

and Reeside "2 miles northwest of Ojo Alamo 

store, in an arroyo north of Ojo Alamo Arroyo, 

at a horizon 25 feet below the upper conglomerate of Sinclair and Granger [that is, in the Kirtland shale]. There is no lower conglomerate 

here." (See locality 60, section F, Pl. LXIV.) 

Other trachodont remains. 

Specimens sufficiently characteristic to be 

identified as pertaining to the Trachodontidre 

were found by the Bauer party in the localities 

described in the followll..1g paragraphs. The 

localities are indicated by numbers on the map 

(Pl. LXIV). 

"Canyon Ojo Amarillo, 2 miles east of Chaco 

River, 10 miles south of San Juan River" (locality 14, section B). Fruitland formation. A 

pair of ma:xillre containing badly shattered -

teeth. In the better-preserved maxillary there 

are 42 vertical rows of teeth, a feature that 

would of itself serve to distinguish this specimen from all known Lance trachodonts, which, 

as shown by specimens in the United States 

~ational Museum collections, have from 52 to 

57 vertical rows. The borders of the teeth are 

smooth, as in the upper jaw of Kritosaurus, 

but in the type of that genus there are 47 vertical rows, so that until the range of variation 

in the number of rows is determined it would 

be unsafe to refer the present specimen to the 

genus Kritosaurus. The length of the dental 

series is 367 millimeters, whereas in the type 

of Kritosaurus navajovius Brown it measures 

410 millimeters. 

"View Point, 5 miles northwest of Pina Veta 

China" (locality 35, section C). Kirtland shale. 

Small portion of the dentary of a trachodont 

dinosaur. 

''View Point, 5 miles northwest of Pina Veta 

China" (locality 34, section C). Farmington 

sandstone member of the Kirtland shale. Dis-
VERTEBRATE FAUNAS OF THE OJO ALAMO. 285 

tal end of a humerus and centrum of a caudal feet above lower conglomerate" (locality 63, 

vertebra. section F). Ojo Alamo sandstone. Fragmen-

"About 23 miles south of Farmington, near tary teeth. 

the reservation line, 1 mile north of Brimhall "North side of Barrel Spring Arroyo, about 

Store" (locality 46, section D). Uppermost 1! miles southwest of Ojo Alamo store; 20 feet 

part of the Kirtland shale. Two anterior cau- below the lower conglomerate" (locality 66, 

dal vertebrre of a large individual. section F). Uppermost part of the Kirtland 

"About 30 miles south of Farmington and 4 shale. Considerable part of the dentary with 

miles east of reservation line" (locality 80, sec- fragments of teeth. The teeth have papillate 

tion E). Lowermost part of the Kirtland borders, and it appears likely that this spedshale. Phalanges and cervical vertebrre. men pertains to the genus Kritosaurus. 

"About 4~ miles northwest of Ojo Alamo "One mile east of Pina Vita China, about 20 

store, on head of Hunter Wash; 25 feet below feet below the conglomerate" (locality 42, secOjo Alamo" (locality 53, section E). Upper- tion C). Upper part of the Kirtland shale. 

most part of the Kirtland shale. Right femur Portion of a left dentary. 

of very large individual. 

"About 2 miles south of Fruitland, 100 feet 

above the top of the Pictured Cliffs sandstone" 

(locality 6, section A). Fruitland formation. 

Centrum of a caudal vertebra. 

"One mile north of west of Ojo Alamo store; 

25 feet below the upper conglomerate of Sinclair and Granger. There is no lower conglomerate at this point; it is apparently consolidated 

with the upper" (locality 62, section F). Uppermost part of the Kirtland shale. Portion of 

the dentary. 

"About 1~ miles southwest of Ojo Alamo 

store, half a mile west of wagon road; 8 feet 

above base of lower conglomerate of Sinclair 

and Granger" (locality 65, section F). Ojo 

Alamo sandstone. Axis with fused odontoid 

process. This specimen was submitted to 

Barnum Brown, of the American Museum of 

Natural History, New York, who reports: "The 

axis with fused odontoid process is probably 

trachodont, possibly Kritosaurus, but it does 

not agree with any of the material we have in 

our collections." 

"One mile north of west of Ojo Alamo store, 

in small basin north of Ojo Alamo Arroyo; 20 

feet below the conglomerate of Sinclair and 

Granger, lower and upper combined" (locality 

62, section F). Uppermost part of the Kirtland shale. Two caudal vertebrre and portions 

of a pelvic bone. 

"Three miles northwest of Ojo Alamo store; 

40 feet below the lower conglomerate" (locality 

56, section E). Uppermost part of the Kirtland shale. Portion of the right dentary. 

Family CERATOPSIDlE Marsh. 

Monoclonius? sp. 

The first Monoclonius-like remains from the 

Ojo Alamo sandstone were reported by Brown 1 

in 1910. He says: 

The ceratopsian fragments were small sections of characteristic squamosal bones, not collected, and part of a 

supraorbital horn, No. 5798 of the American Museum collection. Both ends of this specimen are broken, but very 

little is gone from the upper end. It is 120 millimeters 

long, 180 millimeters in circumference at the base, and 

90 millimeters in circumference at the upper end; subovate 

in cross section and strongly decurved near the upper end, 

having a greater curve on the convex than on the concave 

surface. It is much smaller and lacks the vascular grooves 

that characterize the horns of the genus Triceratops and, 

judging by the form and size, approaches nearest Monoclonius recurvicornis, of the Judith River formation, from 

which, however, it is distinct. Jf. recurvicornis is proportionately shorter and more robust. The squamosal 

fragments of another individual observed in the field were 

much thinner than that bone in the genus Triceratops but 

similarly marked by deep vascular grooves. The horn 

and other skull fragments were apparently from a mature 

animal representing a ceratopsian genus smaller than 

either Triceratops or Torosaurus, but the remains are too 

fragmentary for characterization. 

The Bauer collection contains fragmentary 

ceratopsian remains from no less than seven 

localities. The better-preserved specimen (catalogue No. 7347, U. S. N. M.), from Amarillo 

Canyon, "10 miles south of San Juan River 

and 2! miles east of Chaco River" (locality 

18, section B, Pl. LXIV), "150 feet above the 

base of Fruitland formation," consists of the· 

coossified atlas, axis, third and fourth cervical 

''North side of Barrel Springs Arroyo, half a 1 Brown, Barnum, The Cretaceous Ojo Alamo beds of New Mexico,. 

with description of the new dinosaur genus Kritosaurus: Am. Mus. Nat. 

mile . west of wagon road from Ojo Alamo; 10 Hist. Bull., vol. 2s, pp. 26&-269, 1910. 
286 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

vertebrre, considerable portions of several dorsal and caudal vertebrre, parts of two pubes, 

and fragments of other bones. All this material apparently pertains to one individual. 

In figure 29 are shown comparative views of 

the anterior cervicals of Triceratops prorsus, 

Monoclonius eras sus, and the specimen here illscussed. The distinctness of the latter two 

from Triceratops is at once apparent, and while 

in a general way the anterior cervicals of the 

present specimen approach those of M. crassus, 

II III 

B 

IV 

quite possible that if more perfect material 

were available it might be found referable to 

some of the other genera now known from the 

Judith River, Belly River, and Edmonton formations, but regardless of the uncertainty of 

the generic disposition of this specimen, it represents one of the primitive ceratopsians, none 

of which are found in deposits younger than 

the Edmonton·. 

Specimens sufficiently characteristic to be 

identified as pertaining to ceratopsian dinosaurs 

c 

FIGURE 29.-A, Anterior cervical vertebrre of Triceratops prorsus Marsh, type, No. 1822, Yale Mus., one-eighth natural size. a, Anterior face of 

atlas; p, posterior face of fifth vertebra; r, rib; s, neural spine of axis; s', neural spine of fourth cervical; s", neural spine of fifth cervical; z', 

posterior zygapophyses. (After Marsh.) B, Atlas, axis, and third and fourth cervical vertebrre of Monoclonius crassus Cope, No. 3998, Am. 

Mus. Nat. Hist., as seen from the left side, type, one-fourth natural size. a, Anterior end; p, posterior end; I, II, III, IV, cervicals. (After 

Hatcher.) C, Atlas, axis, and third and fourth cervical vertebrre of Monoclonius?, No. 3347, U.S.N. M., one-fifth natural size. 

a detailed comparison shows many minor differences, sufficient to indicate at least their specific distinctness. The dorsals shown in figure 30 also indicate the close resemblance of 

this specimen to Monoclonius. 

On account of the close resemblance of these 

bones I now refer the material provisionally to 

the genus Monoclonius. That it represents one 

of the so-called primitive ceratopsians there 

can be no question, for its relatively small size 

would of itself distinguish it from all known 

ceratopsians of the Lance for~ation. It is 

were found by the United States Geological 

Survey expedition of 1915 at the following 

localities (shown on Pl. LXIV) : 

"North side of Barrel Spring Arroyo, about 

1 mile south of Ojo Alamo store, 1,000 feet west 

of wagon road; 11 feet above base of lower conglomerate of Sinclair and Granger" (locality 

67, section F). Ojo Alamo sandstone. Fragments of ceratopsian teeth. 

"About 4 miles west of Farmington, a quarter 

of a mile east of Mesa Point, and 1 mile south of 

San Juan River; 40 feet below the Wasatch 
VERTEBRATE FAUNAS OF T'HE 0.!0 ALAMO. 287 

conglomerate" (locality 8, section A). Uppermost part of the Kirtland shale. Proximal 

portion of an ischium (No. 8359, U. S. N. M.) 

of a ceratopsian dinosaur. This bone can be 

clearly distinguished from the ischia of Triceratops, but I am unable to identify it with 

any of the other ceratopsian genera, though 

its small size shows it to pertain to some of the 

smaller members of the group. 1 

"North side of Barrel Spring Arroyo, about 

I! miles southwest of Ojo Alamo store; 1 foot 

above base of lower conglomerate of Sinclair 

and Granger" (locality 69, section F) Ojo 

Alamo sandstone. Fragments of the 

frill of a ceratopsian dinosaur, not 

determinable. 

''North side of Barrel Sp:r_ing Arroyo, 1! miles southeast of Ojo Alamo 

store; 15 feet above 'base of Ojo 

Alamo" (locality 68, section F). Ojo 

Alamo sandstone. Fragments of the 

frill of a ceratopsian dinosaur. The 

deep radiating vascular impressions 

on the upper surfaces of these fragments are very similar to those found 

in the genus Triceratops. Brown 2 has 

evidently found similarly grooved 

bones. He says: 

Family ANXYLOSAURIDlE Brown. 

The presence of armored dinosaurs in the 

deposits of the San Juan Basin is now shown 

by the discovery of a right humerus (No. 8360, 

U. S. N. M.) collected by J. B. Reeside, jr., 

"2 miles northwest of Ojo Alamo store, 20 feet 

below the conglomerate" (locality 59, sec-· 

tion E). Kirtland shale. 

This specimen was placed in the hands of 

Mr. Barnum Brown, of the American Museum 

of Natural History, who reports as follows: 

The humerus is that of a genus of the Ankylosauridre. 

It agrees in size and form with one of our specimens from 

The squamosal fragments of another individual observed in the field were much thinner than that bone in Triceratops but similarly 

marked by deep vascular grooves. The horn 

and other skull fragments were apparently 

from a mature animal representing a ceratopsian genus smaller than either Triceratops or 

Torosaurus, but the remains are too fragmentary for characterization. 

FIGURE 30.-Median dorsal vertebra>, anterior view: A, Monoclonius, No. 8347, 

U. S. N. M., one-fourth natural size. B, Monoclonius crassus Cope, No. 3998, 

Am. Mus. Nat. Hist., one-fourth natural size. c, Capitular. (After Hatcher.) 

Similar fragment.s discovered in 1908 by 

James H. Gardner, of the United States 

Geological Survey, near the head of Coal Creek, 

1 mile southeast of Ojo Alamo, were identified 

by me as pertaining to the genus Triceratops. 

It would now appear that this identification was 

1n error. 

"North side of Barrel Spring Arroyo, half a 

mile west of wagon road from Ojo Alamo; 

10 feet above 'lower' conglomerate" (locality 

63, section F). Ojo Alamo sandstone. Teeth 

of a ceratopsian dinosaur, not determinable. 

1 Since the above observations were written this specimen was sent 

to Mr. Barntim Brown, of the American Museum of Natural History, 

and he reports as follows: "The ischium is undoubtedly that of Monoclonius. It agrees in form and size with that of a skeleton collected last 

year from the Belly River of Alberta-Monoclonius jlexus." 

2 Am. Mus. Nat. Hist. Bull., vol. 28, p. 269, 1910. 

the Belly River of Alberta. I have not yet named this 

genus but am working on it. This genus is typical of the 

Belly River of Alberta and not found in the Edmonton or 

Lance formations. 

Suborder THEROPODA. 

Family MEGALOSAURIDlE. 

Deinodon? 

Plate LXXIII, figures 1 and 4. 

In the collection made by Sinclair and 

Granger in 1913 were separate teeth which 

Brown3 has provisionally identified as pertaining to the genus Deinodon. 

The Bauer collection also contains detached 

teeth that are identical in every way with those 

a Sinclair, W. J., and Granger, Walter, Paleocene deposits of the Sa:1 

Juan Basin, N.Mex.: Am. Mus. Nat. Hist. Bull., vol. 33, p. 303, 1914. 
288 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

figured by Leidy1 as Deinodon horridus (see solidated with the upper" (locality 62, section 

Pl. LXXIII, fig. 4), but in view of the paucity F). Kirtland shale. Tooth of carnivorous 

of our knowledge concerning the complete dinosaur. 

dentition of the several genera of carnivorous "Two miles northwest of Ojo Alamo store; 

dinosaurs now named, and especially as the 20 feet below the conglomerate of Sinclair and 

few dentitions known show so considerable a Granger" (locality 59, section E). Upper part 

degree of differentiation of the teeth in differ- of Kirtland shale. Median phalange of small 

ent parts of the jaws, the provisional reference carnivorous dinosaur; tooth of large carnivoof detached teeth to a genus based on such rna- rous dinosaur. 

terial is in the highest degree conjectural and "North side of Barrel Spring Arroyo, half a 

can serve no useful purpose. If such material mile west of wagon road from Ojo Alamo; 10 

were discussed under the heading" carnivorous fE;}et above 'lower' conglomerate" (locality 63, 

dinosaurs" quite as much information would section. F). Ojo Alamo sandstone. Teeth of 

be conveyed to the reader and the discussion carnivorous dinosaurs. 

would perhaps be less misleading. In Plate LXXIII, figure 1, is shown a left 

Specimens like these have no value for dentary (No. 8346, U.S.N. M.) of a carnivocorrelation, as similar teeth are found in the rous dinosaur collected by J. B. Reeside, jr., 

Judith River, Belly River, Two Medicine, and "28 miles south of San Juan River and about 

Lance formations. 12 miles east of theN avajo Reservation line at 

A list of localities and horizons where the head of Hunter Wash" (locality 60, secdetached teeth of carnivorous dinosaurs were tion F, Pl. LXIV), froin the upper part of 

found is given below: the Kirtland shale. In this bone are sockets 

Five miles west of Pina Veta China; in Farm- for 13 large teeth, but except a germ tooth in' 

ington sandstone member of Kirtland shale, the ninth alveolus from the front all the others 

100 feet above its base (locality 47, section D, have been lost. This germ tooth is compressed 

Pl. LXIV). laterally, lenticular in section in the upper porA single tooth (Pl. LXXIII, fig. 4; No. tion, and serrate on both borders. It is indis8355, U. S. N. M.) resembling in nearly every tinguishable from some of the detached teeth 

detail the D-shaped tooth figured by Leidy.2 found at other localities by the Bauer party. 

"One mile south of camp No. 6, 30 miles The 13 alveoli occupy a space about 354 millisouth of Farmington, 1 mile east of reserva- meters long. At the third alveolus the dentary 

tion; upper part of coal-bearing beds, 10 feet on the external side had a depth of 93 milliabove highest coal" (locality 76, section ~). 1

1\fieters; at the eleventh alveolus it is 110 milliFruitland formation. Tooth fragments of car- meters deep. As in the other Cretaceous 

nivorous dinosaur. Theropoda, the alveolar partitions expand in-

" About 39 miles south of Farmington and ternally into interdental rugosre. 

4' miles east of reservation line" (locality 80, In the number of tooth sockets this jaw 

section E). Lower part of Kirtland shale, 350 agrees with Dynamosaurus imperosus Osborn,a 

feet above base. Fragmentary teeth of car- but in the general form of the dentary, parnivorous dinosaurs. ticularly the contour of the anterior end, it 

"North side of Barrel Spring Arroyo, about approaches Albertosaurus 4 (Dryptosaurus) 

a mile south of Ojo Alamo store, 1,000 feet most nearly, but as the dentary of Albertowest of wagon road; about 11 feet above base saurus has sockets for 15 teeth the presence of 

<>f 'lower conglomerate' of Sinclair and 13 in this individual would appear to show its 

Granger" (loc~lity 67, section F). Ojo Alamo distinctness. 

sandstone. Tooth of large carnivorous dino- It is quite possible that this dentary persaur. tains to the genus Deinodon, but that can not 

"One mile north of west of Ojo Alamo store; be determined at this time because the dentary 

25 feet below the upper conglomerate of Sin- of that genus is unknown. The identification 

clair and Granger. There is no lower conglomerate at this point; it is apparently con1 Leidy, Joseph, Extinct Vertebrata from the Judith River and Great 

Lignite formation of Nebraska: Am. Philos. Soc. Trans., vol. 11, pl. 9, 

figs. 41-45, 1859. 

2 Idem, figs. 41, 42. 

of this specimen must therefore await the discovery of additional material. 

a Osborn, H. F., Tyrannosaurus and other Cretaceous carnivorous 

dinosaurs: Am. Mus. Nat. Hist. Bull., vol. 21, p. 263, 1905. 

f Idem, p. 265. 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 289 

Order CROCODILIA. 

The presence of crocodiles in the San Juan 

Basin is shown by numerous shed teeth in the 

collection made by the Bauer party in 1915. 

Differences observed in these teeth would appear to indicate the presence of two or more 

species, but it is quite impossible to identify 

species or even genera from these simple conical teeth. Similar teeth have been frequently 

found in the Judith River, Belly River, Two 

Medicine, and Lance formations, and until 

identifiable specimens are found these detached 

teeth can have no value for correlative purposes. 

Crocodile remains were collected 

at the localities shown in Plate 

LXIV and described below. 

"One mile south of camp No. 6, 

30 miles south of Farmington, 1 

mile east of reservation" (locality 

76, section E). Fruitland formation. 

Teeth. 

"About 30 miles south of Farmington and 4 miles east of reservation line" (locality 80, section E). 

Lower part of Kirtland shale. 

Teeth and limb bone. 

"North side of Barrel Spring Arroyo, about a mile south of Ojo 

Alamo store" (locality 67,' section 

F). Oj o Alamo sandstone. Teeth 

and dermal scute. 

Brachychan1psa teeth have been found in 

two localities in the San Juan Basin, both 

in the Kirtland shale-" 30 miles south of 

Farmington and 4 miles east of the reservation 

line," and "30 miles south of San Juan River 

and 5! miles east of the reservation line, on a 

tl'ail up Hunter Arroyo" (locality 72, section 

E, Pl. LXIV). 

Order CHELONIA. 

Altogether eight genera and nine species of 

fossil turtles are now recognized from the Ojo 

Alamo sandstone and the immediately underI 

/ 

"One mile north of west of Ojo 

Alamo store" (locality 63, secFIGURE 31.-Carapace of Neurankylus eximius Lambe. Type. Museum oftheCanada 

Geological Survey, Ottawa. One-third natural size. (After Lambe.) 

tion F). Ojo Alamo sandstone. Tooth. 

Family ALLIGATORIDJE. 

Bmchychampsa sp. 

The genus Brachychampsa1 is based on a 

well-preserved skull containing teeth, from the 

Lance formation as exposed on Hell Creek, 

Mont. 

In the Bauer collection are detached teeth 

which I am unable to distinguish from those 

of the type specimen of Brachychampsa and 

which in all probability should be referred to 

that genus. The United . States National 

Museum collections contain similar teeth from 

the Judith River and Lance formations, so 

that in the present state of our knowledge these 

detached teeth have no value as formation 

indicators. 

t Gilmore, C. W., A new fossil alligator from the Hell Creek beds of 

Montana: U.S. Nat. Mus. Proc., vol. 41, pp. 297-302, pis. 26-27, 1911. 

lying formations. Of the eight recognized 

species only one has been found elsewhere, 

the others being based on specimens obtained 

from these deposits. Unfortunately, at least 

half of these species are founded on very fragmentary specimens, for the most part fragments 

of the car a pace. 

Family PLEUROSTERNIDJE Cope. 

Genus NEURANKYLUS Lambe. 

The genus Neurankylus was established by 

Lambe2 in 1902 upon a somewhat fragmentary 

speoimen from the Belly River formation as 

exposed on Red Deer River in the Province of 

Alberta, Canada. The type · consists of the 

posterior two-thirds of a carapace, from which all 

the peripheral bones are missing. (See fig. 31.) 

2 Lambe, L. M., On the vertebrata of the Mid-Cretaceous of theN orthwest Territory: Contr. Canadian Paleontology, vol. 3, pt. 2, pp. 42, 43, 

text fig. 7, 1902. 
290 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

The great width of the vertebral scutes, the 

presence of a ninth pair of costals, and a 

greatly enlarged-- eighth neural were considered a combination o{ characters sufficient 

to separate it generically from all described 

forms. Its family affinities were thought by 

Lam be to be with the Chelydridre. 

In 1908 Hay 1 removed this genus to the 

Baenidre and defined the genus Neurankylus 

as follows: 

A genus of uncertain position and known only from a portion of the carapace of the type species. Eighth neural 

large, followed by an expanded suprapygal. In the type 

a ninth pair of costal bones. The vertebral scutes nearly 

twice as wide as long. 

The presence of an extra pair of costals in 

the type of Neurankylus eximius is considered 

by Hay an individual variation and therefore 

not of classificatory value. The large size of 

the eighth neural, as suggested by Lambe and 

as now shown by the type of Neurankylus 

baueri, was brought about by the coalescence 

of the last neural with the suprapygal and on 

that account can not be considered a diagnostic 

character. It will thus be observed that so· 

far as the type species is concerned the great 

width of the vertebral scutes constitutes the 

principal character for distinguishing this 

genus. 

The specimen discussed below is, on account 

of the close resemblance of its vertebrals to 

those of Neurankylus eximius, provisionally 

referred to the genus Neurankylus. The discovery of better-preserved specimens in the 

Belly River formation may possibly show the 

generic distinctness of these individuals but· 

in the light of our present knowledO'~ the 

evidence points to their being congeneric. 

The genus Neurankylus may now be defined 

~s follows: Carapace depressed; neurals with 

mterrupted, obtuse, dorsal carina; mesoplastrals meeting narrow on the midline; inguinal 

buttresses barely reaching borders of fifth and 

sixth costals; vertebrals very broad as compared to their length. · 

The close resemblance of the present specimen to the genus Glyptops shows it to be a true 

member of the Pleurosternidre, so that now this 

family is represented in North America by the 

genera Glyptops and N eurankylus. 

1 Hay, 0. P ., The fossil turtles of North America: Carnegie Inst. 

Washington Pub. 75, pp. 93, 94, text fig. 90, 1908. 

Neurankylus baueri Gilmore, n. sp. 

Plates LXXIV, LXXV; text figures 32 and 33. 

Type: No. 8344, U. S. N. M., consisting of a 

complete carapace and plastron. Collected by 

C. Max Bauer and J. B. Reeside, jr., 1915. 

Locality: "About 30 miles south of Farmington and 4 miles east of reservation line," 

San Juan Basin, San Juan County, N. Mex. 

(Locality 80, section E, Pl. LXIV.) · 

Horizon:· Lower part of the Kirtland shale. 

The specimen on which this species is founded 

is a beautifully preserved shell, lacking only some 

minor fragments. Dorsoventrally it is considerably depressed, but the outlines of the carapace and plastron are little distorted and give 

a good idea of the form of the living animal. 

In its general form the carapace is broadly oval, 

broad behind, with scalloped borders posterior 

to the inguinal notches, and regularly rounded 

in front with the exGeption of a slight median emargination. Even aside from effect 

of the vertical crushing the shell was still 

depressed. 

At the center the carapace has a greatest 

length of 560 millimeters. Its greatest width 

is 480 millimeters. The entire border anterior to the inguinal notches is thickened and 

rounded, but posteriorly it thins out to an 

acute edge. All the peripheral bones flare 

upward. This upward inclination is most pronounced along the sides, where it forms a wide, 

shallow gutter, much as in Glyptops plicatulus 

(Cope). (See fig. 32.) 

Delicate striations cross the sutures at right 

angles, and faint scutal growth markings on the 

marginals constitute the ornamentation of the 

carapace. 

On the median line, within the third, fourth, 

and fifth vertebrals, are short, obtuse elevations, 

but elsewhere there is no indication of any 

carina. The sulci are narrow and moderately 

impressed. The sutures have all coalesced, but 

by means of the transverse lines mentioned 

above the courses of nearly all of them can be 

accurately traced. 

There are eight neural plates. All except the 

sixth, which is octagonal, and the seventh, 

which is subrectangular, are hexagonal, with 

the widest end forward. Their principal dimensions are as follows: 
VERTEBRATE FAUNAS OF T'HE OJO ALAMO. 291 

Dimensions of neurals in Neurankylus baueri, in millimeters. The pygal has a greatest length at the center 

No. Length. Width. 

1 ......... 60 46 

2 ......... 48 40 

3 ......... 55.5 42 

4 ......... 56 45 

No. Length. 

5 ........ 50 

6 ........ 55 

7 ........ 26 

8 ........ 30 

Width. 

40 

52 

30 

43 

of 40 millimeters, and a greatest width on the 

free border of 60 millimeters. 

There are eight pairs of costals, there being 

no evidence of a ninth pair, as found by Lambe 1 

in the type specimen of Neurankylus eximius. 

They gradually decrease in width from front to 

back, only the eighth being relatively wider 

than the one immediately preceding it. 

FIGURE 32.-Carapaoe of Neurankylus baueri Gilmore, n. sp. Type, No. 8344, U.S.N. M. One-fourth natural size. 

The nuchal is 73 millimeters long, 52 millimeters wide on the free border, and has a maximum width of 92 millimeters. 

The first suprapygal has the form of a 

trapezoid, being 27 millimeters long and 64 

millimeters ·wide. The second suprapygal is 

lozenge-shaped, 40 millimeters long and 120 

millimeters wide. 

The border of the carapace is made up of 

11 pairs of peripheral bones, and all excepting the third, fourth, and sixth extend entirely 

mesiad of the costoperipheral sulcus. The 

first has a height of 60 millimeters; the third, 

59 millimeters; the fifth 64 millimeters; the 

1 Lambe, L. M., On Vertebrata of the Mid-Cretaceous of the Northwest Territory, pt. 2: Contr. Canadian Paleontology, vol. 3, p. 42, fig. 7, 

1902. 
292 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

seventh, 71 millimeters; the ninth 84 millimeters; the eleventh, 70 millimeters. 

The vertebral scutes are very broad compared to their length, as in N eurankylus eximius Lambe. These scutes, however, are relatively longer than in the · species just mentioned. Their sides are strongly bracket 

shaped. 

The nuchal scute is small and subrectangular in outline, and its greatest diameter is anteroposterior. Its length is 19 millimeters; 

its width on the free border 14 millimeters. 

The supracaudal scute is divided, as in Hadrianus. 

On account of the great breadth of the vertebrals and the considerable mesiad extension 

FIGURE 33.-Plastron of Neurankylus baueri Gilmore, n. sp. Type, No. 8344, U.S.N. M. One-fourth natural size. 

The principal measurements of these scutes 

are given below. 

Dimensions of scutes of Neur.ankylus baueri, in mill·imeters. 

Width GreatNo. Length. in est 

front. width. 

1 ......... : ................... 81 110 133 

2............................. 106 93 165 

3 ........................... ~. 110 125 167 

4............................. 114 117 140 

5............................ 108 82 117 

of the inguinals the costal scutes have the 

rather unusual proportion of being as broad as 

long. 

The marginal scutes alternate with the peripheral bones. The fourth, fifth, and seventh extend inward across the costoperipheral 

suture, but all the others are external to this 

suture. 

The plastron (Pl. LXXV; text fig. 33) has 

a total length of 416 millimeters. It is broad 

in front, as in other members of the Pleuro-
VERTEBRATE FAUNAS OF THE OJO ALAMO. 293 

sternidre. The posterior lobe is tapenng; tbe 

narrowed end truncated, with a very slight 

median emargination. The concavity of the 

plastron would indicate this individual to be a 

male. 

The anterior lobe is 111 millimeters long and 

at the base 168 millimeters wide. At the 

gular-humeral sulcus it measures 123 millimeters in width. The front of the lobe has a 

thickened, rounded margin. At the center it 

measures 12 millimeters in thickness. The 

posterior lobe at the center is 122 millimeters 

long and 185 millimeters wide at the base. 

The lateral borders converge rapidly from the 

inguinal notch backward to the truncated posterior end. 

The bridge has a width of 195 millimeters. 

The epiplastra meet on the midline by a 

suture 30 millimeters long; the hypoplastra for 

120 millimeters, the mesoplastra for 30 millimeters, the hypoplastra for 95 millimeters, and 

the :xiphiplastra for 88 millimeters. 

The buttresses are rather narrow, as in other 

Pleurosternidre. The axillary extends well 

upward toward the verte brre on the under side 

of the first costal. The inguinal buttress rises 

little if at all above the costoperipheral suture. 

The intergular scutes meet on the midline 

for 40 millimeters, and they overlap the entoplastron. The gulars do not meet on the midline or overlap the entoplastron. The humerals 

meet on the midline for a distance of 79 millimeters, the pectorals for 100 millimeters, the 

abdominals for 60 millimeters, the femorals for 

58 millimeters, and the anals for 64 millimeters. 

There are four inframarginal scutes. 

Family BAENID.lE Cope. 

.Baena nodosa Gilmore, n. sp. 

Plate LXXVI; text figures 34 and 35. 

Type: No. 8345, U. S. N. M.; consists of a 

nearly complete carapace and plastron. The 

principal parts missing are portions of the posterior border at either side of the middle. Collected by J. B. Reeside, jr., and John Brittain, 

September 8, 1915. 

Locality: "Two miles northwest of Ojo 

Alamo store," San Juan County, N. Mex. 

(See locality 60, section F, Pl. LXIV.) 

Horizon: Kirtland shale. 

The veryrough surface ornamentation of the 

carapace of the type specimen is especially 

characteristic of this species, and this feature 

alone will serve to distinguish it from all other 

described forms. The ornamentation consists of a series of rounded nodelike elevations 

of irregular shapes and unequal sizes placed 

without definite arrangement. Along the central portion of the carapace these node swellings are elongate anteroposteriorly, with narrow longitudinal grooves between. Interspersed here and there among ·the elongate 

nodes are short, rounded elevations. Lateral 

to the vertebral areas the nodes are more 

widely scattered, and the valleys between 

them are wider and deeper. The peripheral 

surfaces are comparatively smooth. 

In form the anterior end of the carapace is 

obtusely pointed. Proceeding posteriorly the 

lateral borders are divergent to a point posterior to the inguinal notches, where they 

round into the wide, truncated posterior end. 

This end has a decided median emargination, 

at each side of which the border is sealloped. 

The number of these scallops can not be determined in the present specimen. The sulci are 

narrow and shallowly impressed, but most of 

those of the carapaee ean be clearly traced. 

The sutures, however, have been obliterated 

through coossification, and are to be observed 

only between a few of the costals. (See 

fig. 34.) 

The greatest length of the earapace at the 

center is 354 millimeters; the greatest width, 

which is posterior to the inguinal notches, is 

344 millimeters. The depth of the shell at 

the center is 80 millimeters, but in life this 

measurement was considerably greater. 

The nuehal scute, relatively of large size, 

has a length of 23 millimeters and a width 

on the free border of 19 millimeters; its greatest 

width is 27 millimeters. 

The vertebral scutes when compared with 

those of other species of the genus are relatively narrow. As in Baena hatcheri Hay, 

from the Lance formation, an accessory lateral 

scute is cut off from each side of the first vertebral, thus greatly reducing it in size. But 

B. nodosa differs from B. hatcheri Hay in having a large nuchal scute that takes the place 

of the extremely small first vertehi'al and forms 

scutellre as in B. hatcheri. 
294 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

The sides of the vertebrals are but little scute, the fifth vertebral coming to the postel'ior 

enlarged laterally at their centers. Their margin. 

principal dimensions are given in the table. The emargination on the posterior border is 

59 millimeters wide. At its center the bone 

Dimensions of vertebrals of Baena nodosa, in millimeters~ is thickened to 12 millimeters, thus forming an 

obtuse median ridge that continues well forLength. W~~th G~~~t- ward toward the middle of the fifth vertebral 

front. width. 

Number. 

scute. 

1.----------------- -----.- -. 2 ..••••. .................... 

3 ••••••...•.•.•.•.•........ . 

4 .••••........ : ............ . 

50 

82 

81 

76 

54 

24 

54 

66 

61 

49 

The plastron (fig. 35) is comparatively 

62 smooth, having only a finely granulated sur-

~6 face. The concave natUl'e of the plastron 

71 would indicate this individual to be a male. 

5 ...... ···--······· -- ...... . 93 The plastron has a greatest length of 323 mil-

----------'-------'----'---- limeters. The sides of the plastron, beginning 

with the bridges, rise upward and 

outward clear to the margin of the 

shell, so that the margin stands 

considerably above the level of the 

plastron. 

The anterior lobe is 81 millimeters 

long and 113 millimeters wide at the 

base. The width diminishes gradually to the gular-humeral sulcus, 

where it mea;ures 71 millimeters transversely. It is slightly notched at 

this point and again where the gularintergular sulcus crosses the margin. 

The anterior border is slightly emarginate. 

The limits of the entoplastron can 

not be traced. The bridge is 149 

millimeters wide. 

The posterior lobe is 89 millimeters 

long and 132 millimeters wide at the 

base. The posterior end is truncated 

and has a shallow but broad emarginated border. At the femeroanal 

FIGURE 34.---Carapace of Baena nodosa Gilmore, n. sp. Type, No. 8345, U.s.N. M. sulcus the sides of the lobe are slightly 

About one-fourth natural size. constricted. 

The triangular supernumerary lateral scutes 

are each 44 millimeters anteroposteriorly and 

54 millimeters transversely. The nuchal has 

on each side a small triangular marginal scute 

with a free border 16 millimeters in length. 

The second marginal is extremely narrow fore 

and aft (11 millimeters) but has a length on 

the free border of 27 millimeters. The third 

marginal extends back from the border 18 

millimeters; the fourth 26 millimeters; the 

seventh 62 millimeters; the eighth 59 millimeters. The number of marginals can not be 

determined in this specimen. As in other 

species of this genus there is no supracaudal 

By means of the striations on the bones the 

limits of the mesoplastrals can be accurately 

determined. They meet rather broadly on the 

midline for a distance of 36 millimeters and 

expand toward the outer margins of the 

shell. All the other sutures are largely obliterated on account of the complete coossification 

or fm~ion of the bones. 

There are distinct gulars and intergulars, all 

of about the same shape and size, as in Baena 

hatcheri Hay. These scutes all start from a 

common point at the midline. The intergulars 

meet at the midline for a distance of 29 millimeters; the humerals for 61 millimeters; the 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 295 

pectorals for 61 millimeters; the anals for 47 

millimeters. The median longitudinal sulcus 

appears to follow a tortuous course, as in several other species of the genus. 

On the bridge there are four large inframarginal scutes. These appear to lie principally 

on the plastral bones, though extending over 

·on to the peripherals. 

This species is distinguished from all others 

in the rough, nodelike ornamentation of the 

carapace, in the triangular shape of the shell, 

and in having the greatest breadth posterior 

to the inguinal notches. 

Thescelus rapiens Hay. 

Text figure 36. 

Thescelus rapiens Hay, The fossil turtles of 

North America: Carnegie Inst. Washington Pub. 75, pp. 97-98, text figs. 

91-92, 1908. 

Sinclair and Granger, Am. Mus. Nat. 

Hist. Bull., vol. 33, p. 303, 1914. 

The original description is as follows: 

This species is represented by a single 

-shell, which was collected from " Laramie" 

-deposits 1 at Ojo Alamo, San Juan County, 

N.Mex., in 1904, by Mr. Barnum Brown, of 

the American Museum of Natural History. 

·The catalogue number of the specimen is 

·6066. The shell has been damaged consid-

·erably by weathering and ·Jacks a portion 

·of the carapace in the nuchal region, some 

portions of the right costals, most of the peripherals, the front of the plastron, and the 

rear of the xiphiplastrals. 

Dimensions of vertebrals of Thescelus rapiens, in millimeters. 

No. Length. Width. 

1. -------------------- · ·········-.. ··· 50± 

2......... . ........... . ... .. . . . . . .. . . . 75 

3. --. .. ........ ... . . .. . .......... . ... 81 

4..... . ................. . ..... . .. . ... 61 

5 .. - .... --- .. - .... -.. -.. -...... -........ -- .. ----- ... .. - ............ --

82± 

92 

92 

92 

86 

On the left side there is a supernumerary costal scute. 

This has been cut off, mostly from the first costal proper 

but to some extent from the second marginal. The fourth 

marginal shown on the left side has a height of 57 millimeters, rising somewhat on the costals. 

The length of the carapace must have been 

dose to 400 millimeters; the width about 375 

millimeters. Apparently the shell was con- .siderably depressed. The front of the cara- FIGURE 35.-Plastron of Baena nodosa Gilmore, n. sp. Type, No. 8345. u. s. N. M. 

About one-fourth natural size. 

pace over the neck was excavated, but not 

:so deeply as in T. insiliens. The area occupied by the 

vertebral scutes presents a broad, shallow, longitudinal 

·channel; but in this, over the neural bones, there is a 

low ridge. The free borders of the anterior peripherals 

are rather obtuse. . 

The sutures of the shell are obllterated, but a few of 

them may be traced by the fine striations which cross 

them. So far as they can be made out, they are shown in 

the diagrammatic figures. The scutal areas are distinctly 

marked on the shell. They present various irregularities. 

'The vertebrals lfig. 06, A] are broader than long; their 

·dimensions are shown in the table below: 

tIn a letter to me dated February 26, 1916, Mr. Brown says:" Thescelus 

rapiens came from the lower conglomerate just below the old Indian trading store in Ojo Alamo," or from the Ojo Alamo sandstone.-C. W. G. 

The plastron [fig. 36, B] is large. From a low ridge 

which joins the iree border of the front lobe with that of 

the hinder lobe the bridges ascend at an angle with the 

remainder of the plastron. The axillary notch is far forward, falling about 55 millimeters behind the front of 

the carapace. The opening for the head and legs is thus 

considerably restricted. The front lobe extended evidently much beyond the front of the carapace. Its length 

can not be determined. The width ot the base is 150 

mlllimeters. The bridge is 167 millimeters wide. The 

length of the hinder lobe was approximately 100 millimeters; the width at the base is 165 millimeters. It 

narrows rather rapidly backward, so that at the femoroanal sulcus the width is 104 millimeters. 

There are at present large mesoplastra, the boundaries 

of which can be pretty satisfactorily determined. These 

• 
296 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

are about 35 millimeters wide at the midline, but they 

expand to about 85 millimeters at the peripherals. 

The median longitudinal sulcus runs a very irregular 

course, and across the femorals it can not be distinguished 

with certainty. The humerals occupy 70 millimeters of 

the midline; the pectorals, about 90 millimeters; the abdominals, about 35 millimeters; the femorals, about 52 

millimeters. The femoroanal sulcus runs far forward 

from its starting point on the border of the plastron. 

Probably on account of weathering the sculpture of the 

carapace is nearly obliterated, appearing only in a few 

spots. On the plastron it is more distinct. It appears 

to have resembled that of T. insiliens and consists of narrow and low ridges and tubercules. Some traces are 

observed of the ridges due to the growth of the scutes. 

A 

Family DERMATEMYIDlE Gray. 

Basilernys nobilis Hay. 

Text figure 37. 

Basilemys nobilis Hay, U. S. Nat. Mus. Proc., vol. 38, pp. 

316-317,textfigs.12, 13,1910. 

The type specimen of this species, No. 6555, 

U. S. N. M., was collected by J. H. Gardner 

and J. W. Gidley at Ojo Alamo, N. Mex., in 

1909. It was found below the upper conglomerate in the dinosaur-bearing deposits and 

"about 50 feet above the lower conglomerate"-therefore in the Ojo Alamo sandstone. 

B 

FIGURE 36.- Thescelusrapiens Hay. A, Carapace; B, plastron. Type, No. 6066, Am. Mus. Nat. Hist. About one-sixth natur~l size. (After Hay.) 

This species differs from T. insiliens in having the 

nuchal less deeply excavated, in having a median depression along the back, and in having the hinder lobe of the 

plastron more rapidly reduced in width backward. In 

T. insiliens the bridges are considerably wider than the 

base of the hinder lobe. 

It should be added that the type of T. 

insiliens mentioned above is from the Lance 

formation of Wyoming. 

At the present time T. rapiens Hay is known 

only from the type specimen. 

The specimen consists of many fragmentary 

parts of both the carapace and plastron. The 

best-preserved part is the border of the right 

side of the posterior lobe of the plastron, including a portion of the hypoplastron and a 

part of the xiphiplastron. 

Hay's original description follows: 

The right extremity of the fragment of hypoplastron 

reaches out to the suture with the eighth peripher~l. 

From this suture to that between the hypoplastron and 
VERTEBRATE FA UN AS OF T'HE O.JO ALAMO. 297 

the xiphiplastron, following the curve, is 102 millimeters. 

Near the former suture the bone is 52 millimeters thick. 

From the border of the inguinal notch a wall extends 

backward along the border of the hinder lobe. At the 

hypoxiphiplastral suture this wall arises 40 millimeters 

above the lower surface of the plastron. From the summit of the wall the bone slopes downward rapidly and 

about equally on the outside and the inside of the wall. 

·where the slope ceases on the inner side of the wall the 

xiphiplf!.stron is about 17 millimeters thick. Passing 

backward 40 millimeters the wall is somewhat higher, 

slightly steeper on the outside and overhanging on the 

inner side [fig. 37, A]. At a distance of 60 millimeters 

behind the hypoxiphiplastral suture the wall is 36 millimeters high and still more overhanging on the inner side. 

At the base of the wall here the thickness of the xi phi plastron is 21 millimeters. As the rear of the xiphiplastron is 

approached the wall becomes lower, only 25 millimeters 

where the fragment ends [fig. 37, B]. On the upper surface of the xiphiplastron there is a large oval scar which 

was occupied by the pubis. 

On the lower surface of the outer extremity of the 

hypoplastron are seen the narrow threadlike sulci which 

bound the inguinal scute. This is only 25 millimeters 

A B 

FIGURE 37.-Basilemys nobilis Hay. Type, No. 6555, U. S. N. M. A, 

Section across free border of xiphiplastron 40 millimeters behind hypoplastron; B, section across free border of xiphiplastron 115 millimeters 

behind hypoplastron. Both figures one-half natural size. (After Hay.) 

wide, and it is thrown well out on the extremity of the 

bone. In B. 'Variolosa this scute is much wider and extends medially to the free border of the hinder lobe. On 

the sloping outer face of the xiphiplastral wall, near the 

hinder end of the specimen, is seen a part of the femoraanal sulcus. 

From B. prreclara, described above, this species differs 

in at least one important respect, the inner slope of the 

wall around the border of the hinder lobe of the plastron. 

* * * It differs from B. sinuosa in about the same 

way, for in the latter the upper surface of the xiphiplastron 

slopes rapidly downward toward the central portion of the 

lobe. The writer has not at hand information regarding 

the same region in B. variolosa, but it probably does not 

differ in any important respect from that of B. sinuosa. 

Hay considers the type specimen to represent an individual of "nearly the size of the 

type of Basilemys variolosa (Cope), the type of 

the genus, the plastron of which was about 

670 millimeters long." 

ln the concluding paragraph of the citation 

given above, Hay points out wherein the 

present form differs from all other species of 

the genus, though it is at once apparent that 

its distinctness from the single Judith River 

species, Basilemys variolosa (Cope), has not 

been satisfactoriiy demonstrated. That it 

may pertain to a distinct species is quite possible, though it is perhaps significant that a 

fragmentary specimen of Basilemys sp. (No. 

8024, U. S. N. M.) from the Two Medicine 

formation, which is in part equivalent to the 

Judith River, most closely resembles B. 

nobilis Hay. The lateral ridge on the hinder 

lobe of the plastron in this specimen, while not 

quite so prominent as in B. nobilis, nevertheless forms a distinct wall, as in that species, 

and constitutes a character which distinguishes both of these specimens from all other 

described forms with the possible exception of 

B. variolosa. 

Adocus? lineolatus Cope. 

Plate LXXVIII, figure 4. 

Adocus? lineolatus Cope, U. S. Geol. and Geog. Smvey 

Terr. Bull. [1st ser.], No.2, p, 30, 1874; The Vertebrata of the Cretaceous formations of the West: 

U.S. Geol. Survey Terr. Rept., vol. 2, p. 263, pl. 6, 

figs. 11, 12, 1875. 

Hay, Bibliography and catalogue of the fossil Vertebrata of North America: U. S. Geol. Smvey Bull. 

179, p. 437, 1902; The fossil turtles of North America: 

Carnegie Inst. Washington Pub. 75, pp. 24.7, 248, 

figs. 308, 309, 1908. 

Bowen, The stratigraphy of the Montana group: U.S. 

Geol. Survey Prof. Paper 90, pp. 122, 123, 1915. 

In the collection made by Mr. Bauer from the 

San Juan Basin is a fragmentary turtle (No. 

8348, U. S. N. M.), consisting of the seventh 

peripheral from the left side, associated with a 

few other fragments, collected in the Fruitland 

formation, "1 mile south of Fruitland" (locality 4, section A, Pl. LXIV). Fortunately it 

can be accurately compared with the type of 

Adocus vigoratus Hay, from the same region, 

which also has the left seventh peripheral. 

The finer sculpture of the Bauer specimen, 

which has four to five rows of pits in a line 5 

millimeters long, separates it at once from A. 

vigoratus, which has only three rows in a 5-

millimeter line. This difference in sculpture 

is clearly shown in Plate LXXVIII, figures 3 

and 4. This finer sculpture resembles closely 

that of Adocus? lineolatus Cope, to which, for 

the present at least, this specimen is referred. 

The type of A. lineolatus was obtained on 

Bijou Creek, 40 miles east of Denver, Colo., in 

beds believed to be of Arapahoe age. 
298 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Knowlton 1 has stated: 

Fragments that have been identified as pertaining to 

this species have been found by Lambe in Belly River 

beds of Red Deer River, Alberta, by Barnum Brown in the 

Lance formation on Hell Creek, Mont., and by others in 

the ''Cera tops beds" [Lance formation] of Converse 

County, Wyo. 

According to Hay, "Fragments of costals 

scarcely, if at all, to be distinguished from them 

[A. lineolatus] are found in the collection made 

in the Judith River region for Prof. Cope by 

C. H. Sternberg, in 1870." 

Hatcher 2 has expressed the opinion that the 

reference of Lambe's specimen "may be incorrect." Hay 3 says: 

It is unsafe to identify as belonging to Adocus? lineolatus 

specimens from the Judith River and Laramie beds before 

A B 

It is quite probable that more than one 

species is represented by these fragments, but 

until better material is found I can do no better 

than refer them to the described species, inadequate though that may be. 

Adocus vigoratus Hay. 

Plate LXXVII, figure 2; Plate LXXVIII, figure 3; text 

· figure 38. 

Adocus vigoratus Hay, U. S. Nat. Mus. Proc., vol. 38, pp. 

317-318, pl. 11, fig. 3, text figs. 14-18, 1910. 

The original description is given below: 

The fragmentary remains which are described under the 

above-given name were collected September 3, 1909, by 

Messrs. Gardner and Gidley, at Ojo Alamo, San Juan 

County, New Mexico. The bones were secured below the 

upper bed of conglomerate [Ojo Alamo sandstone], in those 

c 

\ 

\ 

·-------------- _______ ) 

D 

FIGURE 38.-Adocus vigoratus Hay. Type, No. 6554, U. S. N. M. A, First neural; B, first left peripheral; C, section across first left peripheral, 

the upper surface toward right; D, left seventh peripheral; E, section across free border of base of hinder lobe. All figures about one-half 

natural size. (After Hay.) · 

far better materials of the species have been collected from 

the type locality. It is improbable that the same species 

continued from the Judith River epoch to the Arapahoe 

epoch. 

The specimen now before me shows a type of 

sculpture which at once distinguishes it from 

Adocus vigoratus I-Iay, found in the same region, 

a sculpture which agrees in all particulars with 

the description and figures of the type of 

Adocus? lineolatus Cope, so that disregarding all 

preconceived opinions as to what its geologic 

range should be, I conclude that turtles having 

a similar surface ornamentation of the shell 

lived in the Judith River, Ojo Alamo, Belly 

River, Arapahoe, and Lance epochs. 

1 Knowlton, F. H., Remarks on the fossil turtles accredited to the 

Judith River formation: Washington Acad. Sci. Proc., vol. 13, p. 57, 

1911. 

2Stanton, T. W., and Hatcher, J. B., Geology and paleontology of 

the Judith River beds: U.S. Geol. Survey Bull. 257, p. 76, 1905. 

a Hay, 0. P., The fossil turtles of North America: Carnegie Inst· 

Washington Pub. 75, p. 248, 1908. · 

beds which furnished remains of dinosaurs. The specimen bears the number 6554 of the catalogue of the U. S. 

National Museum. 

The individual was one of considerable size, the length 

of the carapace having been probably 500 millimeters. 

One neural [fig. 38, A] present is probably the most anterior 

one. It is narrowed in front, notched behind, and crossed 

by the sulcus that passed probably between the first and 

the second vertebral scutes. The length is 68 millimeters 

along . the midline; the width is 40 millimeters. The 

anterior end was about 6 millimeters thick; the posterior, 

10 millimeters. Figure 38, B, represents the form of the 

first left peripheral, while figure 38, C, presents a section 

from the free border to the border that articulated with 

the first costal. The bone is about 53 millimeters wide 

along the anterior border and 67 millimeters high. Its 

greatest thickness is 19 millimeters, and this is the same 

where the bone joined the nuchal and where it joined the 

second peripheral. The free border is obtuse. On the 

upper surface are seen part of the first vertebral scute, 

a part of the first costal scute, and parts of the first and 

the second marginal scutes. The ascending plate of one 

of the bridge peripherals is penetrated by the extremity of 

a rib. 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 299 

Figure 38, D, presents a view of the left seventh peripheral. Its length near the free border is 73 millimeters; 

its height is 96 millimeters. The free border is subacute. 

The border is greatly thickened, to form a shoulder to 

receive the inguinal buttress of the plastron. This buttress did not rise to the lower borders of the costals. On 

the upper part of the inner face of the bone is a shallow 

groove· in which lay the end of the rib of the fifth costal 

plate. Farther down this rib enters the bone and descends 

a distance of 44 millimeters from the upper border. 

Of the plastron there are present a fragment of the right 

xiphiplastron and the portion of the hypoplastron that 

sends up the right inguinal buttress. Figure 38, E, 

represents a section taken just behind this buttress. 

It shows the thickness of the bone and the form of the 

free border at the base of the hinder lobe. The underside 

of the fragment shows the outer end of the abdominofemoral sulcus. The xiphiplastron is quite thin, the thickness just behind the femoroanal sulcus being only 6 millimeters. The free edge is acute. The sulcus just named is 

directed fo~rd as it moves toward the midline. 

The outer surfaces of all the bones, those of the plastron 

as well as those of the carapace, are ornamented with 

shallow pits arranged in more or less regular rows. The 

rows are directed obliquely to the sutural borders 

of most of the bones [Pl. LXXVII, fig. 2; Pl. 

LXXVIII, fig. 3]. There are three rows of pits in 

a line 5 millimeters long. The ridges between the 

pits are rounded on their summits and the cross 

ridges are feeble. 

This species is evidently different from all of 

those described from the eastern region of the 

United States. From A. lineolatus, the type of 

Family PLASTOMENIDlE Hay. 

Plastomenus sp. 

Plate LXXVIII, figure 1. 

The genus Plastomenus is represented in the 

Bauer collection by the complete hypoplastral 

bone (No. 8350, U. S. N. M.) from the left side 

shown in Plate LTI~VIII, figure 1. I am unable at this. time to identify the bone with any 

described species, and on account of its very 

large size am inclined to the opinion that it 

represents a new form but do not feel justified 

in establishing a new species on such meager 

material. Its chief importance here is in being 

the first recognizable specimen of the genus 

Plastomenus found in the San Juan basin. 

The specimen was collected by Mr. Bauer" 5 

miles northwest of Pina Veta China," in the 

Farmington sandstone member of the Kirtland 

shale (locality 33, section C, Pl. LXIV). 

which came from Colorado, the present species FIGURE 39.-Nuchal bone of Aspiileretes vorax Hay. Type, No. 6140, Am. 

Mus. Nat. Hist. About two .. fifths natural size. (After Hay.) differs in having a coarser sculpture, three rows 

of pits in a 5-millimeter line, instead of four or five. 

Compsemys sp. 

Plate LXXVIII, figure 2. 

A number of broken fragments (No. 8349, 

U. S. N. M.) of the upper shell of a small 

turtle were found by Mr. Reeside "on the 

north side of Barrel Spring Arroyo, half a 

mile west of the wagon road from Ojo Alamo, 

in the Ojo Alamo sandstone, 10 feet above the 

lower conglomerate" (locality 63, section F; 

Pl. LXIV). These bones are covered with 

small, rounded pustules that form an ornamentation very close to that of Gompsemys vafer 

Hay, but as other species of this genus have 

a somewhat similar sculpture it would not be 

safe to attempt a specific determination on 

materials so scanty. 

The discovery of these specimens is of importance, however, as recording for the first 

time the presence of the genus Compsemys in 

the Ojo Alamo sandstone. 

30830°--17----20 

Family TBIONYCHIDlE Hay. 

Aspideretes vorax Hay. 

Plate LXXVII, figure 3; text figure 39. 

Aspideretes vorax Hay, 'l'he fossil turtles of North America: 

Carnegie Inst. Washington Pub. 75, pp. 496-497, 

text fig. 651, 1908. 

The original description follows: 

This species was collected from the Laramie deposits 1 

near Ojo Alamo, San Juan County, N. Mex., in 1904, by 

Mr. Barnum Brown. ·The type is in the American Museum 

of Natural History and has the catalogue number 6140. 

The species is represented, as far as known, by only the 

nuchal bone; but this is complete. The length of the bone 

from side to side is 200 millimeters in a straight line, 

215 millimeters over the curve. The lateral convexity is 

considerable and appears to have been somewhat greater 

than that of either A. austerus or A. fontanus, both from 

1 In response to my inquiry as to the exact geologic position of the type 

specimens of Aspideretes vorax, A. fontanus, and A. austerus Barnum 

Brown, in a letter of February 26, 1916, writes as follows: "The three 

species of Aspideretes came from clays interbedded in the sandstone of 

the upper part of the Ojo Alamo formation.'' It should be added that 

this determination is based on Bauer's columnar section, which Brown 

had before him.-C. W. G. 
300 SHORTER CONTRIBUTIONS · TO GENERAL GEOLOGY, 1916 • 

. the same locality as this species. The width at the midline is 45 millimeters; the greatest width 55 millimeters. 

The greatest thickness is 15 millimeters. There is a moderate median sinus in the anterior border. This border is 

not clipped off at a nearly right angle with the upper surface, as in the two other species mentioned above, but is 

beveled down on the upper surface of the bone to a sharp 

edge. This beveled surface is not sculptured. The 

hinder border of the bone presents a median excavation, 

"75 feet below the Ojo Alamo sandstone, in 

dinosaur beds." Mr. Gidley tells me that the 

position as stated _above was an estimate of the 

distance, and he is of the opinion that the 

specimen came from above the lower conglomerate and therefore from the Ojo Alamo 

sandstone. 

for the preneural bone. The latter bone was evidently Aspideretes austems Hay. 

unusually broad, the excavatiQn having a width of at Plate LXXVII, figure 1; text figures 40 and 41. 

least 55 millimeters. The preneural border is thicker than 

that of A. fontanus, the thickness being 7 millimeters. Aspideretes austerus Hay, The fossil turtles of North AmerThe sculpture of the bone is obscured by a layer of hard ica: Carnegie Inst. Washington Pub. 75, pp. 495-

matrix; but so far as can be determined it was inter- 496, text figs. 649-650, 1908. 

mediate between A.jontanus and A. auste:rus, approaching d · · f 1 more closely the latter. · The original _ escnption IS as ol ows: 

Certain fragments of costals present probably belong to The fragmentary specimen on which the present species 

this species but possibly to A; fontanus. One of these, _is based was collected in 1904 by Mr. Barnum Brown, from 

,.---........... ---~_ .. ' 

t 

I 

\ 

\ 

' t 

\ I 

I' •-- -~t I I 

' I ' t I I 

l \ . ! ~. _,., : \ __ ... -- ·-~", ~-- --.,~''"".._.._ __ ... -:- ,- \ 

I 

FIGURE 40.-Parts of nuchal and first costalsof Aspideretes austerus Hay. Type, No. 6068, Am. Mus. Nat. Hist. About two-fifths natural size. 

(After Hay.) 

apparently the right sixth, is 35 millimeters wide at the 

neural border, 30 millimeters wide more distally, and has a 

thickness of 8 millimeters. 

This species differs frpm A. jontanus in having the free 

anterior border of the nuchal beveled, the bone thicker at 

the preneural border, and a coarser sculpture. From 

A. auste:rus it differs in having a nuchal with greater anteroposterior width, the bone not so thick, and with the free 

anterior border beveled off instead of being clipped off at 

a right angle with the upper surface. 

A specimen in the United States National 

Museum (No. 6550) has been questionably 

identified by Hay as pertaining to the abovenamed species. It consists of a portion of the 

nuchal and other parts of the carapace and 

plastral bones. In Plate LXXVII, figure 3, 

are shown portions of two costal plates, 

selected to show the character of the ornamentation. 

This specimen was collected in 1909 by 

Messrs. Gardner and Gidley in San Juan Basin 

Laramie deposits [see footnote, p. 295] at Ojo Alamo, San 

Juan County, N.Mex. The catalogue number of the spec 

imen is 6068. The remains, belonging apparently to a 

single individual, consist of the nuchal except the central 

portion, part of both first costals, the greater part of a right 

posterior costal, probably the sixth, various fragments of 

costals, a piece furnishing parts of two neurals, and a considerable portion of the right hypoplastron. 

The species is characterized by the very thick bones and 

the coarse sculpture of both the carapace and plastron. 

On account of the missing middle region of the nuchal, 

the exact lateral extent of this bone can not be determined. 

It was, however, not far from 230 millimeters, being thus 

somewhat less than that of A. fontanus, just described. 

The greatest width is 45 millimeters, a fourth less than that 

of A. fontanus. The greatest thickness of the bone is 21 

millimeters. The free anterior border is not beveled but 

is cut off at nearly right angles with the upper surface, like 

that of the species just mentioned. The thickness of this 

border varies from 10 millimeters toward the midline to 

15 millimeters near the outer end. 

The first costal is about 72 millimeters wide near the 

neural border, and it increases to 80 millimeters near the 

distal end. The free border 'is cut off at a nearly right 
VERTEBRATE FAUNAS OF THE OJO ALAMO. 301 

angle to the upper surface. The thickness of this border 

is 10 millimeters or more. The hinder border of this bone 

is 10 millimeters thick. 

The posterior, probably the sixth, costal is 25 millimeters 

wide llO millimeters from the distal end, but it widens 

rapidly to 55 millimeters. The free border is like that of 

the first costal. There must have been a considerable 

notch between this costal and the one next 

behind. In thickness this costal ranges 

between 9 millimeters near the proximal 

end and 10 millimeters at the distal end. 

The sculpture of the carapace is best displayed toward the free borders. It consists of abruptly sunken pits, of which 

there are usually five in a line 20 millimeters lorig. Closer to the free borders the 

pits are smaller. Nowhere does there appear any tendency for the formation of 

straight rows of pits, such as are seen on 

the costals of Amyda cariosa, of the New 

Mexico Wasatch. On the portions of the 

The fragment of a costal plate (No. 8351) 

shown in Plate LXXVII, figure 1, is identified 

provisionally as pertaining to the present species. It agrees with the type specimen in being 

thick and heavy and especially in the character 

of the surface ornamentation, which is made 

carapace near the midline the pits are less FIGURE 41.-Right hypoplastron of Aspideretes austerus Hay. Type, No. 6068, Am. 

conspicuous. They appear to be as large, Mus. Nat. Hist. About two-fifths natural size. (After Hay.) 

but the walls appear worn down. 

The hypoplastron [fig. 41] is thick and heavy. At the 

suture with the hypoplastron, not far from the midline, the 

thickness is 13 millimeters. One border of the notch for 

the process of the xiphiplastron remains. This bone was 

articulated with the hypoplastron by a jagged suture, and 

it must have extended anteriorly near the midline. The 

outer end of the hypoplastr?n, near the bases of the lateral 

, ... ,;----- I 

I 

I 

I 

I 

I 

\ 

\ 

...,,------

' .. _--.,'\,,,--

!L ... -.. ( ./ ' : l 

, .... 

up of abruptly sunken pits without definite arrangement in rows. It was collected by Mr. 

Bauer 28 miles south of San Juan River (see 

locality 51, section D, Pl. LXIV), "about 250 

feet above the Pictured Cliffs sandstone," in 

the Fruitland formation. 

_ .... 

\ 

\ 

\ 

' \ 

\ 

\ 

\ 

.... ...,• 

Aspideretes fontanus Hay. 

Text figure 42. 

Aspideretes fontanus Hay, The fossil turtles 

of North America: Carnegie Inst. 

Washington Pub. 75, pp. 494-495, 

text fig. 648, 1908. 

The original description follows: 

From the Laramie beds [see footnote, p. 295] 

at Ojo Alamo, San Juan County, N. Mex., 

Mr. Barnum Brown, of the American Museum of Natural History, in 1904 brought 

materials belonging apparently to three 

species of the genus Aspideretes. Of these 

the present is represented by nearly the 

whole of the right half of the nuchal and a FIGURE 42.-Parts of nuchal and first right costal of Aspideretesjontanus Hay. Type, No considerable part of the right first costal. 

6070, A.a. Mus. Nat. Hist. About two-fifths natural size. (After Hay.) The number of the specimen is 6070. 

processes, is 16 millimeters thick. Evidently nearly the 

whole lower surface of the plastron was covered by the 

sculptured layer. The pits are smaller than those of the 

carapace, there being about seven pits in a line 20 millimeters long. Many of them coalesce to form winding 

furrows. 

This species differs from A. fontanus in having a narrower nuchal, much thicker bones, and a considerably 

coarser sculpture. It is referred to Aspideretes provisionally. 

At no point does this piece of nuchal come to the midline; hence we can not determine the exact extent of the 

bone laterally. It was, however, not far from 260 millimeters. The animal was therefore one of considerable 

size. The inner hinder angle of the bone presents a part 

of the sutural border for the preneural, and from this to 

the outer end of the nuchal is 125 millimeters. The width 

of the bone where it came in contact with the preneural 

is 60 millimeters. The anterior border is not beveled but 

is cut off nearly at right angles with the upper surface. 
302 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

The greatest thickness, through the ridge on the lower surface, is 16 millimeters. Where it made contact with the 

preneural the thickness is only 4 millimeters. 

The portion of the costal, the proximal half, almost 

certainly belongs to the same individual. At its proximal 

end it presents the sutural borders for the preneural and 

the first neural. Evidently the preneural was somewhat 

wider than the neural. Its length was at least 40 millimeters. The border of the costal for union with the neural is 7 millimeters thick. About the middle of the length 

of the hinder border of the costal the thickness is 7 millimeters. 

The upper surface of the bone is incrusted with a layer 

of iron oxide, but so far as can be discovered the sculpture 

was :finer than in the other two species found in that 

region, A. austerus and A. vorax. The few pits observed 

appear to be about 2.5 millimeters in diameter. 

The respects in which this species differs from those 

just named are mentioned under their respective descriptions. 

Class PISCES. 

Two genera of fishes have been provisionally 

identified from the deposits in San Juan Basin. 

On account of the close similarity between 

them and the fish remains found in the Judith 

River, Belly River, Two Medicine, and Lance 

formations, they are of little value for correlation, although they give some indication of the 

character of the fish that inhabited the waters 

at the time these deposits were laid down. 

Myledaphus sp. 

Plate LXXVII, figure 4. 

Myledaphus bipartitus Cope, Acad. Nat. Sci. Philadelphia 

Proc., 1876, p. 260. 

This genus of pavement-toothed fish is represented by a considerable number of detached 

teeth (No. 8356, U. S. N. M.) found by Mr. 

Bauer's party "30 miles south of Farmington 

.and 4 miles east of the reservation line," in 

the lower part of the Kirtland shale (locality 

SO, section E, Pl. LXIV). Teeth of this pattern are found in the Lance, Judith River, and 

Belly River deposits. The teeth found by the 

Bauer party can not be distinguished from 

teeth .from the Judith River described by Cope 

as Myledaphus bipartitus, but it would be quite 

impossible to identify species from teeth of 

such simple pattern. 

Lepisosteus sp. 

Plate LXXVII, figure 5. 

The genus Lepisosteus was founded on 

lozenge-shaped scales. Similar scales occur in 

the Lance, Two Medicine, Judith River, and 

Belly River formations, and the present specimens probably represent more than one species, but the material is too inadequate to 

identify species. These scales have been found 

in the San Juan Basin in the localities named 

below: 

''One mile south of camp No. 6, 30 miles 

south of Farmington, 1 mile east of reservation; 10 feet above highest coal" (locality 76, 

section E, Pl. LXIV) . . Fruitland formation. 

"About 30 miles south of Farmington and 

4 miles east of Teservation (locality 80, section 

E). Kirtland shale. 

"North side of Barrel Spring Arroyo, about 

1 mile south of Ojo Alamo store, 1,000 feet 

west of wagon road; 11 feet above base of 

lower conglomerate of Sinclair and Granger" 

(locality 6_7, section F). Ojo Alamo sandstone. 

"About 30 miles south of San Juan River 

and 5!- miles east of the reservation line, on 

trail up Hunter Arroyo" (locality 72, section 

E). Kirtland shale. 

"One mile north of west of Ojo Alamo store; 

25 feet below the upper conglomerate of Sinclair and Granger [locality ·62, section F]. 

There is no lower conglomerate at this point; 

it is apparently consolidated with the upper." 

Upper part of Kirtland shale. 

''North side of Barrel Spring Arroyo, half a 

mile west of wagon road from Ojo Alamo; 10 

feet above lower conglomerate" (locality 63, 

section F). Ojo Alamo sandstone. 
PLATES LXXII-LXXVIII. 

303 
... 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXII 

A. SKULL OF KRITOSAURUS NAVAJOVIUS BROWN. 

Type. No. 5799, Am. Mus. Nat. H ist. About one-sixth natural size. A comparison with B shows that the nasal 

bones have not been properly restored. (After Brown.) 

B. SKULL OF KRITOSAURUS NOTABILIS (LAMBE). 

In the museum of the Geological Survey of Canada, Ottawa. Originally described as the type of Gryposaurus 

notabilis. About one-sixth natural size. (After Lam~e.) 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXIII 

• 
PLATE LXXIII. 

FIGURE 1. Left dentary of carnivorous dinosaur, possibly pertaining to the genus Deinodon. No. 8346, U. S. N. M. 

About one-third natural size. 

FIGURE 2. Right scapula of Kritosaurus? sp. No. 8354, U.S.N. M. About one-fourth natural size. 

FIGURE 3. Lower tooth of Kritosaurus navajo'vius Brown. Type. No. 5799, Am. Mus. Nat. Hist. Internal view. 

Enlarged 1! diameters. (After Brown.) 

FIGURE 4. Tooth of carnivorous dinosaur. No. 8355, U.S.N. M. a, Lateral view; b, end view. Enlarged 2 diameters. 

This tooth resembles closely one figured and described by Leidy as pertaining to Deinodon horridus. 

FIGURE 5. Right dentary of Kritosaurus na'vajovius Brown. Viewed from the internal side. Type. No. 5799, Am. 

Mus. Nat. Hist. About one-fifth natural size. (After Brown.) 

305 

U.S. GEOLOGICAL SURVEY 

PROFESSIONAL PAPER 98 PLATE LXXIV 

CARAPACE OF NEURANKYLUS BAUER!. 

Type. No. 8344, U.S. N. M. Dorsal view. One-third natural size. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXV 

PLASTRON OF NEURANKYLUS BAUERI. 

Type. No. 8344, U. S. N. M. Ventral view. One-third natural size. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXVI 

A. CARAPACE OF BAENA NODOSA. 

Type. No. 8345, U. S. N. M. Dorsal view. One-fourth natural size. 

B. PLASTRON OF THE SAME SPECIMEN. 

Ventral view. One-fourth natural size. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXVII 

2 

1 

4 5 
PLATE LXXVII. 

FIGURE 1. Aspideretes austerus Hay. Distal end of costal plate. No. 8351, U. S. N. M. Natural size. Shows the 

abruptly sunken pits which form the characteristic ornamentation of the carapace. 

FIGURE 2. Adocus vigoratus Hay. Type. No. 6554, U.S.N. M. A part of a peripheral above the bridge to show the 

orname:p.tation. The upper border of the bone is toward the left. Natural size. (After Hay.) 

FIGURES 3, sa. Aspideretes vorax Hay. Costal plates to show the ornamentation. No. 6550, U.S.N. M. Natural size. 

FIGURE 4. Myledaphus sp. Tooth. No. 8356, U.S.N. M. Enlarged 2 diameters. 

FIGURE 5. Lepisosteus sp. Scale from the side of the body. No. '8357, U.S.N. M. Enlarged 2 diameters. 

307 
PLATE LXXVIII. 

FIGURE 1. Plastomenus sp. Left hypoplastral bone. No. 8350, U.S. N. M. About three-fourths natural size. 

FIGURE 2. Compsemys sp. Portion of a costal scute. No. 8349, U.S.N. M. Enlarged 2 diameters. 

FIGURE 3. Adocus vigoratus Hay. Seventh peripheral, left side. No. 6554, U.S.N. M. Natural size. 

FIGURE 4. Adocus? lineolatus Cope. Seventh peripheral, left side. No. 8348. U.S.N. M. Natural size. 

308 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LXXVIII 

2