1916] 



Dickerson: Tejon Eocene of California 



463 



the area of the San Luis Quadrangle and he states that the area was 

 probably an insular mass during Eocene time. No Eocene is reported 

 from the San Juan district in southeastern San Luis Obispo County. 



The coal of the Stone Canon area in the southeastern corner of 

 Monterey County is Miocene in age and not Eocene. Eocene deposits 

 are lacking in this area and in the rest of the Priest Valley Quadrangle 

 to the north. So far as known, Monterey County does not contain 

 deposits of this age within its borders. 



South of the San Luis Quadrangle, great thicknesses of Eocene 

 strata which are at least in part Tejon were reported by Eldridge. 82 



Lawson 83 mapped no Tejon in the Mount Tamalpais Quadrangle. 

 No Tejon has been reported from Sonoma County. 



The Tejon occupies quite extensive areas in Napa and Solano 

 counties and the three lower zones are probably all represented. Just 

 south, in the Concord Quadrangle, the Tejon has a thickness of about 

 2000 feet. The lowermost zone, the Turbinolia zone, and the second, 

 the Rimella simplex zone, are present. The third zone, the Balano- 

 phyllia variabilis zone, may be represented by the non-fossiliferous 

 beds at the top of the Tejon in this vicinity. The Turbinolia, the 

 Rimella simplex, and the Balanophyllia variabilis zones have their 

 type localities in the area south of Mount Diablo. The uppermost, or 

 Siphonalia sutterensis zone, appears to be entirely absent in the 

 San Francisco Bay region. The reason for this will be discussed later. 



The lone phase of the upper Eocene is found along the eastern 

 side of the Great Valley from Oroville to Fresno River but the other 

 zones are missing here. On the western side of the Great Valley, 

 Tejon is found at frequent intervals from Mount Diablo to the 

 Tehachapi Mountains. At least three zones of the Tejon are present in 

 the Temblor Mountains in the Coalinga District and possibly the 

 uppermost may be represented by a portion of the white shales in the 

 oil fields of Coalinga. At the type locality of the Tejon in the 

 Tehachapi Mountains only the Rimella simplex zone is present. 



Along the coast from Mendocino County to southern San Luis 

 Obispo County, no Tejon has been reported, but the non-fossiliferous 

 Butano formation of the Santa Cruz Quadrangle may belong to this 

 group. West and south of the type locality of the Tejon, however, 



82 Eldridge, G. H., and Arnold, R., The Santa Clara Valley, Puente Hill, 

 and Los Angeles Oil District, Southern California, Bull. No. 308, U. S. Geo- 

 logical Survey, pp. 5-7, 1907. 



Lawson, A. C, San Francisco Folio, No. 193, U. S. Geological Survey, 



1914. 



