62 
EOCENE CliOCODlLIA. 
large teeth of the lower jaw is received into a narrow excavation of the 
border of the upper jaw. 
The dermal bones are coarsely pitted, and no one of the seven pre¬ 
served is carinate. 
Measurements. 
No. 1. 
Width of the parietal bone. 
Width of the frontal at the orbits. 
Depth of the ramus at two canines. 
Depth of the ramus just behind the same. 
Width of the ramus at the symphysis, posteriorly 
Length of a cervical vertebra. 
Diameter of the 
K vertical .. 
transverse 
M. 
0.013 
0. 043 
0. 037 
0. 030 
0. 020 
0. 043 
0. 022 
0. 021 
No. 2. 
M. 
Width of the muzzle at the canine notches. 0. 074 
Width of the nares near the posterior border. . . 0. 030 
Depth of the mandibular ramus at the canines - . 0. 044 
Length of the alveoli of the inferior canines together. 0. 020 
Width of the ranius at the posterior end of the symphysis. 0. 031 
Depth of a cervical centrum in front..... 0.029 
Width of the same... 0.027 
Length of the same. 0. 041 
Length of a lumbar centrum. 0. 045 
Width of a dermal shield. 0. 045 
The size of the Alligator mississigpiensis. 
CROCODILUS, Linn. 
Remains of species of this genus are exceedingly abundant, cliieHy in 
the upper beds of the formation, associated with Garfishes. The lower 
beds contain the greater number of Mammalian remains, with a smaller per¬ 
centage of Crocodiles. The latter do not include any Gavials, and resemble 
in some degree those of the Bridger group; some of the species being prob¬ 
ably identical. 
The New Mexican sjiecies are naturally divided into those with flat 
frontal bone, with the inferior ridges little developed, and those in which 
the interorbital region is bounded below by strong orbital or olfactory 
crests. In the latter, the superior plate is narrower and thicker. 
