40(3 



University of California Publications. [Gkology 



The best preserved specimen of Desmostylus in the University 

 of California collection (figs. 2a and 2b) is unfortunately labeled 

 only with the name of the donor, who is no longer to be found. 



Considering all of the California occurrences of Desmostylus 

 remains concerning which we have any reliable data, there seems 

 good reason to regard it as probably characteristic of the 

 Vaqueros or Temblor horizon, and presumably not occurring 

 much if any higher than the faunal zone of Turritella ocoyana, 

 which marks the upper limit of the Temblor or Vaqueros as 

 commonly recognized. 



Outside of the region of California the only occurrence of 

 Desmostylus known in America is that of a tooth obtained by 

 Professor Thomas Condon from the beach of Yaquina Bay in 

 the northern half of the Oregon coast. This specimen evidently 

 came from middle Tertiary beds which are exposed along the 

 beach, but it is not possible to make certain of the exact horizon 

 from which it was derived. As nearly as can be determined the 

 tooth came either from beds recognized as Oligocene, or from 

 some part of the Miocene. In as much as there are reasons for 

 considering that the marine Oligocene of Oregon may correspond 

 in age to the Temblor or Vaqueros of California, it is possible 

 that the horizon of Desmostylus at Yaquina Bay is close to that 

 of the definitely known occurrences in California. 



Remains referable to Desmostylus are reported by Yoshiwara 

 and Iwasaki 3 from the Tertiary of Japan. They occurred in a 

 tuffaceous sandstone lying some distance above a horizon con- 

 taining many marine shells generally considered to be of Miocene 

 age. Associated with the Desmostylus bones were teeth of a 

 shark (Carcharias japonicus), a marine shell (Solen), and im- 

 pressions of some land plants. The presence of plants suggests 

 that the deposits were formed near shore, and presumably near 

 the mouth of a river. From such information as is available 

 one might consider the Japanese Desmostylus as coming from 

 Miocene beds. 



Considering all of the evidence before us, it is clear that 

 Desmostylus was a marine animal, which may have gone into 



s Yoshiwara, S., and Iwasaki, J., Jour. Coll. Sc. Imp. Univ. Tokyo, vol. 16, 

 art. 6, 1902. 



