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University of California Publications in Geology ['Voi.. 12 



development of three distinct horizons of the late Tertiary and early 

 Quaternary. The determination of the age of these deposits has been 

 especially important in its bearing on the interpretation of local 

 orogenic history and the date of the final elevation of the northwest 

 portion of the San Jacinto Mountain Range, which cannot have been 

 earlier than post-Bautista. The interesting evidence of the fossils is 

 that each of the three new horizons is representative of a faunistic 

 and geographic phase unknown elsewhere. 



Fig. Ic. Section of United States Geological Survey, Elsinore Quadrangle 

 sheet, showing San Timoteo and Eden regions and more important Univ. Calif, 

 localities (San Timoteo, single circles, see p. 319; Eden, double circles, see p. 339). 

 Granitic and metamorphic outeroppings occur about Eden Mountain, Mt. Davis, 

 Lamb Dome, and Potrero Creek. 



Among the more important materials secured are : dentitions illus- 

 trating new transition stages in the evolution of the horse series from 

 early Pliohippus to Equus; the molars of a large Pleistocene tapir, 

 and of a great Pliocene bear more closely resembling Hyaenarctos 

 sivalensis of the Indian Siwalik than any of the two or three previously 

 represented American forms ; remains of four types of ground sloth, 

 and of a number of very interesting varieties of the camel group. 



The three exposures and their faunas are as follows: 



