GEOLOGY OF THE SOUTHERN COAST RANGES 563 
them, and when covered by porous beds vast deposits of bitumen 
have been formed. 
San Pablo formation (Middle Neocene).—Overlying the Mon- 
terey series unconformably is a series of soft sandstones, diato- 
Nonconformity between the San Pablo formation and the Monterey series. 
Ocean cliffs near Pismo. 
maceous beds, and some flinty shales. It forms the eastern 
extension of the San Luis range between San Luis Obispo 
and the ocean, as well as a considerable area in the upper 
Salinas Valley. In the latter region it is filled with fossils which 
indicate the Middle Neocene, but to be more exact, whether the 
uppermost Miocene or the lowest Pliocene is as yet undeter- 
mined. Dr. Merriam has in a recent publication’ described a 
series of strata on the southern shore of San Pablo Bay contain- 
ing a similar fauna which he believes represents a distinct and 
*Bull. Dept. of Geol., University of California, Vol. II, No. 4. 
