1916] Merriam: Mammalian Remains from the Tejon Hills 117 



any of the four Cenozoic faunas of the Mohave Desert. It is pos- 

 sible that they are present in both the Barstow and Ricardo, but 

 have not been recognized. Abundant material is, however, available 

 from both Barstow and Ricardo with no recognized remains of 

 rhinoceroses, while both of the exceedingly scanty collections from the 

 Tejon Hills have included fragments of rhinoceros teeth. The 

 rhinoceros group possibly avoided the peculiar habitat of the Mohave 

 Desert, and may have existed in the California province west of the 

 main divide during the period in which Miocene and Pliocene forma- 

 tions were being deposited in the Mohave area. 



The Merycodus and camel remains of the Chanac fauna are not 

 sufficiently characteristic to give us a determination of the rela- 

 tionship of the Tejon Hills assemblage to that of the Barstow and 

 Ricardo. The single Merycodus tooth is very close in its form and 

 dimensions to teeth from the Ricardo, and may represent the same 

 species. The Merycodus horn fragments are not to be distinguished 

 from types represented in both the Barstow and Ricardo faunas. 



The available evidence furnished by the Chanac mammalian fauna 

 indicates that it represents a stage older than the Pliohippus pro- 

 versus zone of the Upper Etchegoin in the North Coalinga region, and 

 later than the Barstow, the youngest recognized Upper Miocene of 

 the Pacific Coast and the Great Basin provinces. The Chanac is evi- 

 dently of an early Pliocene or latest Miocene phase. It is presumably 

 nearest to the faunas of the lower portion of the Jacalitos-Etchegoin 

 of the North Coalinga region and to the Ricardo stage of the Mohave 

 area. 



DESCRIPTION OP CHANAC MAMMALIAN FAUNA 



EHINOCEROTID AND MASTODONTINE EEMAINS 



In the earlier discussion of the Tejon Hills fauna a fragment of a 

 large tooth, 4 at first assumed to represent a proboscidean, was tenta- 

 tively considered as a member of the Rhinocerotidae, as the structure 

 of the outer wall closely resembled that of rhinoceros tooth forms. 

 In the collection obtained in 1915 a portion of a large rhinoceros 

 lower cheek-tooth furnishes satisfactory evidence of the presence of 

 this group in the Chanac fauna. This tooth fragment, no. 22368, 

 represents a large animal of uncertain systematic position. The pres- 

 ence of a rhinoceros in the Tejon Hills fauna is a matter of consider- 



* Merriam, J. C, op. cit., fig. 6, 1915. 



