406 O. C. Marsh—Reptilia of the Baptanodon Beds. 
A single vertebra, apparently of this genus, was obtained by 
the writer, in 1873, in eastern Oregon, and with it a Zrigonia, 
both found in the Blue mountains. The locality was not visited 
by the writer, and he has no conclusive evidence that the 
horizon, apparently Jurassic, is the same as that in the Como 
region where the type of Baptanodon was found. 
FIGURE 2.—Cervical vertebra of Baptanodon natans, Marsh. One-third natural 
size. A, side view; B, front view; C, section; D, top view; a, 
anterior articular face; , neural canal; 7, r’, faces for rib. 
In 1885, a new outcrop of the Baptanodon beds was found 
in the Freeze Out mountains in Wyoming, and here several 
skeletons of Baptanodon were obtained, all in concretions of 
limestone, as in the original locality. One concretion from 
this new locality enclosed the skeleton of a small Plesiosaur 
of much interest, being the first Jurassic form observed in this 
country. This specimen was named by the writer Parasaurus 
striatus, the specific term denoting a characteristic feature 
of the vertebre, which are all strongly grooved, as indicated 
in the one shown in figure 3, below.* This generic name also 
proved to be preoccupied, and was replaced by Pantosaurus,t 
the name of the species now being Pantosaurus striatus. 
oe B C 
: 
lg eS 
SS —a 
Bb 
Figure 3.—Posterior cervical vertebra of Pantosaurus striatus, Marsh. One- 
half natural size. A, side view; B, front view; C, bottom view; 
a, anterior face; n, neural canal; p, posterior face; 7, face for rib. 
The skull in this genus was provided with teeth. The neck 
was long and slender. The vertebrae preserved resemble most 
nearly in form and size those of Plestosaurus plicatus, Phillips. 
Yale University Museum, October 16, 1895. 
* This Journal, vol. xlii, p. 338, 1891. + Report Geological Congress,1891, p. 159. 
