1919] Kcur: Geology of a Part of the Santa Y nez Tiiver District 9 



boulders ranging' in size np to a foot and a lialf in diameter. They 

 consist of chert, trap, porphyries, granites, and rhyolites, and are 

 cemented by a medium-grained, dark-gray sandstone. The Cretaceous 

 strata lying above this conglomerate consist mainly of medium-grained, 

 dark-green sandstone which weathers reddish. Immediately overlying 

 the heavy conglomerate, the sandstone contains angular fragments of 

 limy shale of a composition similar to the impure limestone in the 

 Knoxville below the conglomerate. Thin layers of dark-green shale 

 are interbedded with the sandstone, though the latter is predominant 

 throughout this upper member. 



TERTIARY SYSTEM 



Eocene Series 

 Tejoii Formation 



In a publication by Eldridge and Arnold* relating to neighboring 

 districts, the name Topatopa formation has been used to designate 

 the Eocene strata lying above the Cretaceous and below the Sespe 

 formation and continuous with the Eocene in the Santa Ynez district. 

 Wherever exposed it has yielded typical Tejon and Meganos ( Eocene j 

 fossils and is therefore correlated with these formations, which are 

 widespread over California, so that the name Topatopa becomes 

 superfluous. At the time the field work for this report was done, the 

 Meganos formation'^ had not been recognized. Later, in checking over 

 the fauna, characteristic species of both the Tejon and the Meganos 

 were found. As these formations have not been mapped separately, 

 the Eocene as it occurs in this region will be considered as a whole and 

 called the Tejon. 



In the Santa Ynez River district, the Tejon forms the greater part 

 of the Santa Ynez Mountains, and occupies a broad area immediately 

 north of the Santa Ynez River east of Loma Alta. Its relation to 

 the Cretaceous in this region is not clear, as in no place are the two 

 in contact except on the south slope of Little Pine Mountain, where 

 beds of doubtful Tejon age rest unconformably upon the Cretaceous. 



A typical section of the Tejon as seen on the west side of Oso Creek 

 consists of about 2800 feet of shales and sandstones with minor 



•4 Eldridge, Geo. H. and Arnold, Ralph, The Santa Clara Valley, Puente Hills, 

 and Los Angeles oil districts, southern California, U. S. Geol. Surv. Bull. 309, 

 19'07. 



5 Clark, Bruce L., Meganos group, a newly recognized division in the Eocene 

 of California, Geol. Sec. Am. Bull., vol. 29, pp. 281-296, June, 1918. 



