MIOCENE FORMATIONS. 21 



MiKittrick district, Kern County. 



Ujai ranch and vicinity, Ventura County. 



Santa Inez Mountains, Santa Barbara County. 



San Pedro, Santa Monica Mountains, and east of Los Angeles, i^ot: Angeles County. 



FAUNA. 



The fauna of the Monterey shale is quite limited, and the fossil.s are generally 

 preserved only in the form of casts or mo'ds. Pecten pedxhuini is one of the 

 most abundant fossils, but as it is not confined to the Montere}^ its value as an 

 agent of correlation is onh^ nominal. The most characteristic species appear to be 

 Area montercyatia and a large, coarse-sculptured Lcda. 



Pecten fauna. — The Pecten- fauna of the Monterey (including such species as 

 are found both below and above it, or in its included sandstones, but which, on 

 account of hal)itat, are not found in the typical shale) is as follows: P. andetvo/tl, 

 P. crassicai'do, P. estrella/n/s, P. {Hinnites) giganteus, P. pedroanus^ and P. 

 pechKam i. 



The following species have a more or less uncertain stratigraphic status, and 

 some or all of them may extend into or through the Montere}' or its equivalents: 

 P. howersi, P. carrizoenuls^ P. cerrosenslti \&v. ■mendenhalU, P. discm, P. fucamix, 

 P. keep!, P. lompicoenMH, P. neahensis, P. nutteri, P. perrini, P. /n'opatidua, and 

 /'. stanfordenxis. 



The following species have been found in the ilonterej' shale near the type 

 localit_y or in the Santa Cruz Mountains, just to the north and across Monterey 

 Ba}' from it. 



L'ml oj Moruerey rhale {middle Miocene) fossils. 

 [Those marked ,vith an astensk (*) are supposed to be characteristic.] 



PELEcypoDA. 



* Area montereyana (")sm(int. 

 Callista angustifrons Conrud. 

 Chione mathewsonii (Tabb. 

 *Corbulasp., probably new. 

 Cytherea sp. A. 



* Diplodonta n. sp. (aff. ) serricata Reeve. 

 *Glycyineris (?) n. sp. 



* Leda n. sp. A. 



* Leda n. sp. B. 



* Lutraria traskii Conrad. 



PELECVPOD.A. — continued. 



Pecten andersoni n. sp. 

 Pecten peckhami (iabl>. 

 * Phacoides like crenulata. 

 Saxidoniu.s sp. 

 *Semele n. sp. A. 

 Siliqua sp. 

 *Tellina congesta Conrad. 



r,ASTER0P0D.\. 



Cylichna (cf. ) petrosa Conrad. 



The fauna of the Cariizo ('rsek beds, which are undoubtedly Miocene but of 

 uncertain horizon, belongs to an entirely separate biologic province from that of 

 the principal California Miocene, and for that reason has few species in common 

 with any of the other known California deposits. The following is a list of the 

 fossils so far recognized from the Carrizo Creek beds. (See also list of fo.ssils 

 from Santa Rosalia, Lower California, under Pecten cerro.iemis var. mendenhalU., 

 p. 85.) 



