212 



University of California Publications. 



| Geology 



ment of the fauna. There are differences between the faunas of 

 some of the localities, but the vertical difference in position of 

 these beds is not great, and the variation may be due to factors 

 other than vertical range. 



While the work of collecting was in progress, the question fre- 

 quently arose as to whether any of the mammalian remains 

 obtained at Thousand Creek were derived from Pleistocene 

 deposits. As has been stated above, in those cases where the 

 deposits could be examined, there seemed good reason for con- 

 sidering them as all belonging to one formation, while the 

 palaeontologic evidence indicates that this formation is older than 

 Pleistocene. At one or two localities where loose bones were col- 

 lected on the broad terraces north of the mouth of Thousand 

 Creek, and along the southwestern border of Thousand Creek 

 Basin, remains of horses were obtained which are not distinctly 

 separable from the genus Equus. The presence of remains re- 

 ferred to Equus has suggested that these particular specimens 

 may be derived from Pleistocene deposits resting upon the older 

 beds. Similar remains are, however, found at other localities 

 where the suggestion of Pleistocene age is not so strong. There 

 does not as yet seem to be reason for considering that two faunas 

 are mingled in these deposits. If such mingling occurs the 

 amount of material derived from deposits younger than the 

 Thousand Creek Beds must be very small. 



The collections obtained from localities 1096, 1097, 1100, and 

 1101 are not widely separated geographically, and are from 

 nearly the same horizon, so that they may be taken as a fair 

 representation of the fauna of the Thousand Creek Beds. The 

 species from these localites include the following forms : 



Thousand Creek Fauna, Localities 1096, 1097, 1100, 1101. 



Branta, sp. 



Canis(l) davisi, n. sp. 



Z7m«s(?), sp. 



Felis, sp. a. 



Lepus vetus Kellogg. 



Plioliippus(^) , sp. 



Equus ('?), sp. 

 Teleoceras(l) , sp. 



