350 GEOLOGICAL SURVEY OF THE TERRITORIES. 



PROCAMELTJS. 



An extinct genus established on remains discovered by Professor Hay- 

 den in the pliocene sands of the Niobrara Eiver, Nebraska. Fragments 

 of jaws and teeth exhibit a near relationship in the anatomical charac- 

 ters of the skull to that of the existing members of the camel family. It 

 possessed a greater number of molar teeth than the camels and lamas. 

 Three species of the genus are apparently indicated by the fossil re- 

 mains. 



Proeamelus robustus. — The largest species, founded on a portion of a 

 lower jaw, pertaining to an animal about the size of the living camel. 

 Its teeth were smaller than in the latter, but this difference was fully com- 

 pensated in the greater number of these organs. 



Some additional remains of the same species were subsequently dis- 

 covered by Professor Hayden, on Little White Eiver, Dakota. 



Proeamelus oecidentalis. — A species indicated by a greater number of 

 fossil specimens than the preceding, was about two-thirds the size of 

 the former. Some remains, apparently of the same animal, subsequently 

 discovered on the Little White Eiver, Dakota, lead to the probability 

 that all referred to the species thus named may belong to the female of 

 the former one. 



Proeamelus gracilis. — A small species, not larger than the domestic 

 sheep, indicated by several fragments of jaws and teeth. 



HOMOCA1TELUS. 



An extinct genus, closely allied to the former, to which the above 

 name is given, is iudicated by several fragments of jaws with teeth, ob- 

 tained by Professor Hayden in the pliocene sands of the Niobrara River. 



Romocamelus caninus. — The species, named from the conspicuous char- 

 acter of the anterior teeth of the upper jaw, was about the size of the 

 living lama. 



MERYCODTJS. 



This extinct genus of ruminants was originally founded on a jaw frag- 

 ment discovered by Messrs. Meek and Hayden, in 1853, on Bijou Hill, 

 east of the Missouri Eiver. Subsequently Professor Hayden discovered 

 additional and more characteristic remains of the same, mainly consist- 

 ing of fragments of lower jaws with teeth, on the Niobrara Eiver, and 

 on Little White Eiver. 



Merycodus necatus. — The species was smaller than the domestic sheep. 



PCEBROTHERIUM, 



Another extinct genus of the camel family, was founded on the greater 

 portion of a skull, which was one of the first fossil specimens produced 

 from the great tertiary cemeteries of the West. The specimen was dis- 

 covered by Mr. Alexander Culbertson, in the mauvaises terres of White 

 Eiver, Dakota, and was presented in 1846 to the Academy of Natural 

 Sciences of Philadelphia. The remains of the genus appear to be exceed- 

 ingly rare, as a very few trifling fragments have been since discovered. 

 Pcebrotherium Wilsoni. — The species, approximating in size the domestic 

 sheep, is named in honor of Dr. T. B. Wilson, late of Philadelphia, and a 

 distinguished patron of natural history. 



PROTOMERYX. 



Another extinct member of the camel family, distinguished by the 

 above name, is founded on a jaw fragment obtained by Professor Hay- 



