MIOCENE FORMATIONS. 



17 



The following species have been found in tlie San Lorenzo formation at the 

 type locality, or witliin a radius of four or live miles from it: 



List of San Lorenzn formation (Oligocene) fossils. 

 [Those miirkerl with an asterisk (*| hiive been found !it the type locality.] 



BKACHIOl'ODA. PELECYI'ODA — COIltinUeil 



Terebratula cf. nitens Conrad. 



PELECYPODA. 



Area sp. A. 



*Callista angustifrons Conrad. 



Calli.sta sp. A. 



Cardium (cf. ) breweri Gabb. 



Cardium (La;vicardium?) n. sp. 



Corbula sp. A. 



Cytherea (cf. ) vespertina Conrad. 



Cytherea sp. A. 



Leda, 3 sp., A, B, and ('. 



Macoma nasuta Conrad. 



*Maconia, 2 sp., A and B. 



Modiolus (aff. ) rectus Conrad. 



* Modiolus n. sp.? 



Neai'i-a (aff. ) pectinata Cpr. 



*Nucula n. sp. A. 



Nucula n. sp. A var. 



Ostrea (cf . ) idriaensis Gabb. 



Panopea (cf. ) generosa Gould. 



Pecten peckhami Gabb. 



Pecten sancta?cruzensis n. sp. 



Phacoides acutilineatus Conrad. 



Phacoides (Myrtea?) n. sp. 



Soleniya ventricosa Conrad yo.?. 



Solen n. sp. (aff. ) eurtns Conrad. 



*Xelliua (cf.) arctata Conrad. 



*Tellina (cf. ) oregonensis Conrad. 



Thracia (aff.) trapezoides Conrad. 



Thyasira n. sp. 



Venus (cf. ) lentieularis Gabb. 

 Yoldia impressa Conrad. 



(;.\STEI!OPOD.\. 



Acfeeon sp. A. 



Astyris n. sp. A. 



Bela clathrata Gabb. 



Crepidula prjerupta Conrad?. 



*Cylichna (aff.) petrosa Conr. or horni Gabb. 



*Dentalium near substriatum Conr. or cooperi 



(-iabb. 

 *Dentalium n. sp. A. 

 Doliuni? n. sp.?. 

 Fusus (cf. ) niatbewsonii Gabb. 

 *Fusus (cf. ) oregonensis Conrad. 

 Fusus (aff.) thracius Conrad. 

 * Fusus, 3 n. sp. , A, B, and C. 

 Fusus or Perissolax sp. A. 

 (nalerus excentricus Gabb.?. 

 Galerus (aff.) niaminillaris Brod. 

 *Lunatia (cf. ) shumardiana Gabb. 

 Natica sp. A. 

 Neverita saxea Conrad. 

 *Pleurotonia (aff.) raricostata Gabb. 

 Plenrotoma, 2 sp., A and 1!. 

 Scala (Opalia) sp. .\. 

 Sigaretus scopulosus Conrad. 

 Solarium (aff.) amoenum Conrad. 

 *Solarium n. sp. .\. 



CEPHALOPODA. 



Aturia ziczae Sowerby (?). 



MIOCENE. 



Three divisions are commonly recognized in the Miocene of California, the 

 lower (Vaqueros). middle (^lonterey). and upper (San Pablo). At certain localities 

 the relations existing between these three divisions are very clear, while at others 

 they are obscure, and at still others it appears as if the lower two are interbeclded 

 with etich other to a greater or less extent. In the vicinity of Mount Dial)lo, Doctor 

 Merriam is able to dili'erentiate a fourth division lying between the Monterey 

 shale and the San Pablo, which he calls the Contra Costa County Miocene, and 

 which is characterized, according to him," by (lijpeiixiti' (?) l>r( ii\riainis, Trochifa 

 costellufa^ several new species of Madlolus, etc. This hist horizon has not as j'et 

 been recognized outside of the Mount Diablo Range. 



a Merriam, J. C, Bull. Dept. Geol. Univ. Cal., vol. :'.. .\o. Id, IWM, i>. 37s. 

 17260— No. 47—06 2 



