330 University of California Publications. [Geology 



Thousand Creek, Nevada, and containing remains of a form con- 

 sidered by them to represent the tragocerine or hippotragine 

 division of the antelope group, which has hitherto been known 

 only from Europe, Asia, and Africa. The horn is short and 

 straight, with a round-oval cross-section. Its surface resembles 

 that of the horns of the Bovidae, and differs from the prong-horn 

 antelope in its comparatively coarse pitted structure. 



There is in the University collections a fragmentary specimen 

 from Thousand Creek representing a small portion of a horn 

 core which corresponds very closely in form to about one-third 

 of the horn core of the type specimen Neotragocerus improvisus 

 as figured by Matthew and Cook. The cross-section of the horn 

 core is approximately circular and there is no evidence of the 

 presence of spiral ridges. The core narrows rather sharply 

 toward one end, which presumably indicates that the horn was 

 short. It appears to narrow too rapidly to represent simply the 

 tip of a tragelaphine horn. As nearly as can be judged from this 

 specimen there is good reason to think that it is either a form 

 near Neotragocerus, or is an early representative of the Aplocerus 

 or mountain goat type. 



Associated with the antelopes from Thousand Creek there are 

 a number of representatives of the Merycodus type, and with 

 these there is one specimen which resembles Merycodus, and also 

 suggests Sphenophalos. If the lowest beds of the Virgin Valley 

 formation are found to contain these forms, it might be profitable 

 to consider carefully the possibilities of American origin of some 

 of the antelopes here described. It may also be profitable to 

 consider the relationship of the existing American antelopes or 

 antelocaprines to some of the forms represented in this fauna. 



Issued December 16, 1909. 



