1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 287 



The last stage here recognized was finally brought to a close by a 

 general elevation which, according to the fauna, took place not earlier 

 than mid-Pleistocene time. It lifted the lower San Bernardino and 

 San Jacinto ranges to their present great elevation, and raised and 

 tilted the sedimentary beds of the adjacent basins whose eroded 

 remnants today form the Badlands of the San Timoteo Canon and of 

 Bautista Creek. 



COEEELATION 



Eden. — The Pliocene has been the least known of American Ter- 

 tiary horizons. Only in recent years has a representative fauna been 

 obtained, and the line of division between it and the Miocene can as yet 

 be but loosely drawn. In a recent review Professor J. C. Merriam" 

 has grouped the most important Pliocene land-laid deposits according 

 to the topographical features of the Cenozoic Epoch as follows: (1) 

 the Eastern Coast area, represented principally by the Florida 

 Alachua; (2) the Western Plains region, including the early Republi- 

 can River deposits of northwestern Kansas, the Snake Creek of west- 

 ern Nebraska, and the later Blanco of northwestern Texas; (3) the 

 Great Basin Province, represented by the Ricardo of the Mohave 

 Desert, the Thousand Creek of Nevada, and the Rattlesnake of Oregon ; 

 (4) the Pacific Coast Province, including the Chanac-Etchegoin, and 

 the Pinole Tuff-Orinda. The known deposits of this last province are 

 now increased by the addition of the Eden (see map, fig. la). 



The fauna of the Republican River and the Alacluia is believed, 

 because of the large proportion of characteristic Miocene types, to lie 

 near the border line between the Miocene and Pliocene. The presence 

 of Miocene, together with a host of more modern forms, in the great 

 Snake Creek aggregation suggests the interesting possibility that the 

 same may represent more than one stage of Tertiary life. All of the 

 more advanced forms of this great assemblage are recognized in allied 

 species in the Thousand Creek, the Chanac-Etchegoin, the Rattle- 

 snake, and the Eden formations, in all of which the oreodonts and 

 Hypohippus forms occurring in the Republican River and the Ricardo, 

 and the more primitive of the forms occurring in the Snake Creek are 

 conspicuous by their absence. 



11 Relationship of Pliocene Mammalian Fauna from the Pacific Coast and 

 Great Basin Provinces of North America. Univ. Calif. Publ., Bull. Dept. Geol., 

 vol. 10, pp. 421-443, 1917. 



