Vol. 6] Merriam: Virgin Valley and Thousand Creek. 



303 



America of Old World types of antelopes as presented by the 

 Thousand Creek fauna, Matthew and Cook 3 " have recently 

 described a peculiar antelopine or bovine horn-core, and an ante- 

 lope-like dentition, from the late Tertiary beds of Snake Creek, 

 Nebraska. As noted by Matthew and Cook, the dentition re- 

 sembles that of the twisted-horned forms and not that of the 

 type of antelope represented by the horn-core which has been 

 provisionally associated with the dentition in their description. 

 Inasmuch as the faunas of Thousand Creek and Snake Creek are 

 not widely separated in time, one unavoidably considers the pos- 

 sibility that the teeth of the twisted-horned forms of the Thous- 

 and Creek fauna are not represented among the remains thus 

 far collected at Thousand Creek, while at Snake Creek the teeth 

 of these forms have been found without accompanying horns. 

 Such an explanation seems, however, not to be within the limits 

 of probability. 



It would seem to the writer that with the evidence available 

 we are not in a position to determine the affinities of the Ameri- 

 can twisted-horned antelopes with certainty. So far as can be 

 determined they appear to be near the Antilocapridae, but they 

 are evidently generically distinct from Sphendphalos. If, as 

 seems probable, the only type of dentition known from the Thou- 

 sand Creek Beds really represents this group along with Spheno- 

 phalos, these forms are probably derived with the Antilocapridae 

 from some type like Merycodus, and are not closely related to the 

 Old World strepsicerine forms. If teeth like those obtained by 

 Matthew and Cook at Snake Creek belong to this group it may 

 represent an immigration of typical Old World forms or might 

 be derived from a Palaeomeryx-like American form. 



With the available information it is probably desirable to 

 refer Ilingoceros tentatively to a distinct family, the Ilingoceri- 

 dae, and to include Sphenophalos in the Antilocapridae. 



TRAGOCERAS(?) or ILINGOCEROS 



In a former publication 31 the writer provisionally referred 



so Matthew, W. D., and Cook, H. J., Bull. Am. Mus. Nat. Hist., vol. 26, 

 pp. 413 and 414, 1909. 



si Merriam, J. O, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 330, 

 1909. 



