125 



observes, indicates a species about half the size of E. 3fortoni, the remains 

 of which are found in the Miocene Tertiary deposit of the Mauvaises Terres 

 of White River, Dakota. 



Among the collections of fossils from the Bridger beds I have seen no 

 remains which could be ascertained to belong to this genus. Figs. 28 and 

 29, Plate VII, represent two views of an incisor tooth which looks as if it 

 might pertain to E. Mortoni. The specimen was found by Mr. Pierce, of 

 Denver, twenty miles southeast of Cheyenne City, Wyoming. 



REPTILIA. 



The Bridger Tertiary formation, in comparison with the earlier Tertiaries 

 of White River, Dakota, and of the Niobrara River, Nebraska, is remarkable 

 for the variety as well as the number of its reptilian remains. Amid the 

 multitude of fossils which have been collected in the latter localities nearly 

 all belong to mammals ; and though the remains of turtles are abundant, they 

 appear all to be referable at most to a single species for each locality. No 

 fragment of a crocodilian, lacertian, or serpent has yet been discovered either 

 in the Mauvaises Terres of White River, Dakota, nor in the sands of the 

 Niobrara River, Nebraska. From the Bridger beds there have been col- 

 lected many remains of different species of crocodiles, turtles, lacertians, and 

 serpents. 



Order Crocodilia. 



Body lizard-like in form, with four short limbs and feet, and a long, 

 powerful tail. With long jaws, provided with a siuglc row of teeth inserted 

 in distinct sockets. Skin protected by bony plates. 



CROCODILUS. 



The Bridger Tertiary formation contains numerous remains of crocodiles. 

 Many collected by Professor Hayden's party in 1870, and others obtained by 

 Drs. Corson and Carter during the same and the succeeding year, have been 

 submitted to the inspection of the writer. The specimens were found, in 

 various localities in the vicinity of Fort Bridger, as Little Sandy River, Big 

 Sandy River, Green River, Black's Fork of the same, Church Buttes, Grizzly 

 Buttes, &c. The specimens examined indicate several species, though from 

 their generally detached and imperfect condition we have not been able to 

 collocate them so as distinctly and clearly to establish the species. Some of 



