222 University of California Publications in Geology [Vol. 9 



terey there is a formation composed principally of coarse-grained 

 to conglomeratic sandstone, portions of which are azure blue in 

 color and somewhat resemble part of the San Pablo. On this char- 

 acter Jones has depended for its correlation with the San Pablo, 

 which name he has applied to the formation. Overlying his San 

 Pablo unconformably is his Merced and Purisima. This formation « 

 is about fifteen hundred feet in thickness. It is composed principally 

 of medium and coarse-grained gray sandstone. The correlation of 

 this formation with the Merced and the Purisima was made upon 

 palaeontologieal evidence. 



Dr. J. P. Smith has recently published a paper on the Miocene 

 invertebrate faunas of California. 17 In this paper the author gives 

 a faunal list which include all of the species so far known from 

 these formations, together with the life range of each species. The 

 division between the Miocene and the Pliocene was drawn between 

 the Etchegoin and the Purisima as a matter of convenience, "there 

 being no natural boundary between the two periods." The Purisima 

 was placed with the San Diego Formation and classed as lower Plio- 

 cene. The Merced Series, together with the Santa Barbara, was con- 

 sidered to be upper Pliocene. The name Merced was not used in 

 connection with any of the formations in the south because it was not 

 certain that the term Merced Series was applicable to such formations. 



Merced Series 



Aside from the Merced Series at Seven Mile Beach, there are, 

 in the vicinity of San Francisco Bay, numerous other occurrences 

 of marine sediments which have been recognized as being contem- 

 poraneous in deposition Avith those at the type locality, and to which 

 the name Merced has been applied. One of the largest of these 

 occurrences is to be found in the Santa Rosa Valley a few miles 

 north of the city of Santa Rosa. Another rather large area occurs 

 in the Pajaro River Valley near Sargent Station, Santa Clara 

 County, California. Three smaller areas are situated along the 

 coast, one at Ano Nuevo Bay, another at Pillar Point, and the third 

 at the entrance to Bolinas Bay. There are other marine sediments 

 in this general region, portions of which are the equivalent of the 

 Merced Series at Seven Mile Beach, but these formations have been 



it Proc. Calif. Acad. Sci., 4th series, vol. 3, pp. 161-182, 1912. 



