456 0. C. Marsh— New Fossil Reptiles from 



This species is named for the discoverer, Mr. G. B. Grinnell, 

 of the Yale party, who found a nearly perfect skeleton on 

 Marsh's Fork, in Wyoming, The geological horizon is essen- 

 tially the same as in the three preceding species. 

 Crocodilus hrevicollis^ sp. nov. 



A number of cervical and dorsal vertebrae, found toL'oth.T. 

 and evidently belonging to the same individual, differ so 

 from any known Crocodilian remains that they may bf 

 ered specifically distinct. Among the most noticeabli' ' 

 ters exhibited, are the relative shortness of the atlas w 

 attached odontoid process; and the presence, on or near w:- 

 median line of the lower surface in all the vertebrae preservtd. 

 of a deep elongated pit, which has a tendency in its forward 

 nsion to produce bifid hypapophyses. The eleventh verte- 

 has the process thus divided. Its diapophyses are al?o 

 much elongated, and entirely above the line of the neural arch 

 suture. The articular faces are here broadly oval. 



Length of axis, with odontoid process, 20*5 lines. 



Depth of odontoid process, 9-40 ^^ 



Length of process, - - 6-30 " 



Length of eleventh vertebra, from edge of cup to end 



of ball, 16- i; 



Greatest distance between diapophyses, - - - 21" 



These specimens were found by Mr. A. H. Ewing, in the 

 Tertiary beds, at Grizzly Buttes, Wyoming. 



Olyptosaurus sylvestris, gen. et sp. nov. 



Among the most interesting Reptilian remains discovered by 

 the Yale party in the fresh water Tertiary deposits of western 

 Wyoming, were several species of Lacertidae, or land lizara=. 

 of which no fossil representative had at that time been found m 

 this country, although more recently one species has been ae- 

 scribed by Professor Leidy from the same formation. iii^=^ 

 remains were found associa,ted with the crocodiles and f^^]:' 

 already described,* and, together with them, strikingly i^",^^^;?;^ 

 the remarkable development of reptilian life during the -lerna 

 '. of the great tropical lakes of the Rocky Mountain 



The specunens discovered evidently represent a V^f'^^^^f^l 

 of lizards, quite different from any known recent or fossil to m 

 but in the present preliminary notice only the most maiK^ 

 characters are given, the more exact determination and amn _ 

 of the group being reserved for the full description. -^^6/ 

 in this genus, for which the name Ghjptosaurus f is proposea, 



* Thi< Journal, vol. i, May. 1871, p. 322. 

 f T7.vnTbc, embossed, and 'Lavpog, lizard. 



period in one of the great tropic 



