198 University of California Publications in Geology [Vol. 7 



"Lower Neocene (Monterey). — The rocks of this age usually 

 embrace a heavy body of sandstones, conglomerates, and shales 

 at the base, in which the form Ostrea titan is often found; over- 

 lying these in some places is a body of gypsiferous clays that, 

 in the region of Point Sal, for example, attains a thickness of 

 nearly 2000 feet ; above all is the salient feature of this series, 

 a great body of more or less siliceous shales, everywhere of con- 

 siderable thickness and locally embracing at least 2000 or 3000 

 feet. This succession is not, however, strictly adhered to at all 

 points. The formation is distributed the entire length of the 

 Coast Range from Cape Mendocino to beyond Los Angeles. It 

 borders the coast and occurs in the interior, forming a conspic 

 uous terrane along the great valley of California drained by the 

 San Joaquin and Sacramento rivers." 



A few of his local descriptions will be referred to. "Mon- 

 terey shale" was described from the Santa Cruz district. "For 

 the Coast Range, in general it has already been stated that the 

 lower portion of the Monterey frequently consists of sandstones. 

 The sands here referred to" (in local description) "may be the 

 equivalent of these ; or, on the other hand, it may be that they 

 are simply a shore deposit of uncertain age laid down prior to 

 the deposit of the Monterey shale, and derived in large measure 

 from the adjoining granite or brought into their position by 

 coastwise currents" (pp. 383, 384). 



The Monterey was also reported and briefly described from 

 the Salinas Valley region. San Luis Obispo district, the Santa 

 Maria district. Los Alamos .district, the southern coastal strip 

 of Santa Barbara County, the Chino district (Puente Hills), 

 and the Asphalto district (McKittrick). In many of these local- 

 ities it is said to lie unconformably below the "San Pablo (Middle 

 Neocene)." Sandstones are often reported as intercalated in 

 the shales, or at the base of the shales and either definitely or 

 doubtfully referred to the Monterey. 



Point Arena District. — As Eldridge's is the only published 

 account of the Point Arena district, it is presented here in more 

 detail than the other districts mentioned. 



"This district embraces a small area of Monterey shale lying 

 along the coast about 110 miles north of San Francisco. The 



