28 
MESOZOIC VERTEBRATA. 
, The specimen was originally stated to, me to have been found “near 
the summit of Pike’s Peak,” Colorado. I remarked on this, that “the 
specimen has tlie appearance of having been derived from the Cretaceous 
beds, probably of the Niobrara epoch (No. 3), which are extensively ex¬ 
posed along the eastern base of that mountain.” More full information leads 
to the belief that it was obtained from some point in New Mexico. 
REPTILIA. 
CROCODILIA. 
The only Mesozoic Reptilia discovered by the expedition of 1874 were 
obtained from tlie so-called Triassic red beds of the western side of the 
Sierra Madre, on the Gallinas Creek, as already stated in the geological 
description. They are in a fragmentary condition, but of great interest, as 
being the first fossils discovered in that formation in the Rocky Mountains. 
With the Reptilian remains are the rhomboganoid scales of small Fishes, 
which are abundant in the coprolites of the Crocodiles. The Reptiles repre¬ 
sent three orders of Crocodiles^ Binosauria, and apparently of Sauropterygia. 
The Dinosaurian order is represented by a part of the crown of a tooth of a 
species of large size, of the general character of Lcdaps. Both faces are 
convex, the one more so than the other, and the long axis of the crown is 
curved toward the less convex side. Both cutting-edges are sharply and 
closely crenate-denticulate, as in Lcelaps, Megalosaurus^ &c.; otherwise, the 
enamel is perfectly smooth. There was not enough of this animal discovered 
to enable me to identify it. The suspected Sauropterygian species is repre¬ 
sented by a single vertebra, with the centrum slightly depressed, with circu¬ 
lar section, and about as long as wide. Tlie neurapophysis appears to have 
been united by suture, although this point is not so clear as desirable, and 
the bases of the diapophyses are very stout, extending the entire length 
of the upper half of the lateral surface of the centrum. Of the articular 
faces, one is much more concave than the other. Length of centrum, 
O^.OS; width, 0™.057 ; depth, 0”.055. The Crocodilian remains consist of 
a portion of a jaw-bone with alveoli for four teeth, of a broken vertebra, 
and a number of dermal scuta and fragments of other bones. At another 
