ON MOLLUSCA OF THE WEST COAST OF NORTH AMEKICA, 50? 



period the coast-range was entirely under water. The Miocene beds ar< 

 above 2000 feet in thickness, and abound in fossils generally distinct from 

 those of the eastern strata. There is nothing in California answering to the 

 Northern Drift of the countries bordering on the Atlantic. The molluscs of 

 Dr. Antisell's Survey were described by Mr. Conrad, pp. 180-196. He 

 remarks that " the fossils of the Estrella Valley and Sta. liiez Mountains are 

 qmte distinct from those of the Sta. Barbara beds, and bear a strong resem- 

 blance to the existing Pacific fauna. The Miocene period is noted, both in 

 the eastern and western beds, for the extraordinary development of Pecti- 

 nidcv, both in number, in size, and in the exemplification of typical ideas." 

 It also appears to be peculiarly rich in Arcadce, which are now almost 

 banished from that region, while they flourish further south. The large 

 Amusium canrinum and the delicate Pecten hastatus of the Vancouver district, 

 as well as the remarkable Janira dentata of the Gulf, may be regarded as a 

 legacy to existing seas from the Miocene idea ; otherwise the very few 

 Pectinids which occur in collections along the whole West Coast of North 

 Ac^erica is a fact worthy of note. Mr. Conrad has " no doubt but that the 

 Atlantic and Pacific oceans were connected at the Eocene period;" and the 

 fossils here described afford strong evidence that the connexion existed during 

 the Miocene epoch. All the species here enumerated (except Pecten deserti 

 and " Anomia suhcostata") were believed to be distinct from those collected 

 by the preceding naturalists. 



Dr. AntlselVs Californian Fosr;ih. 



Hitmite^ cntssa, Conr. [?= H. yiyatitea, Gray.] Sta. Mar- 

 garita. 



Pecten Meekii, Conr. San Raphael Hills. 



Pecten deserti, Conr. Blake's GoL, p. 15. Corrizo Creek. 



Pecten discus, Conr. Near Sta. Inez. 



Pecten mmjnolia, Conr. [Probably = P. Jeffersonius, Say, Vir- 

 ginia.] Near Sta. Inez. 



Pecten ai'tipli'catiis, Conr. San Raphael Hills. 



Palliian Edrellanum, Conr. [Janira.'\ Estrella. 



Spoi>di/Ii(s Estrellanus, Conr. [?Janira.'\ Estrella. 



Tapes niontana, Conr. San Buenaventura. 



Titpes Inezensis, Conr. Sta. Inez. 



Venus Pujaroana, Conr. Pajaro River. 



Arcopaf/ia unda, Conr. Shore of Sta. Barbara and Estrella. 

 [Closely resembles A. hiplicata ; ? = Littricoln (dta.'] 



CycJas jJennacra, Conr. Sierra Monica. ResBUibles C. pan- 

 diifa, Conr., =Lticinu compre sa, Lea. 



Cyclas Estrellana, Conr. Estrella. 



Area Ohispoann, Conr. San Luis Obispo. 



Pao^ifflrvmn Inezana, Conr. [Like P. crassatelloides.'] Sta. 

 Inez Mt8. 



Crassuteiut eoUina, Conr. Sta. Inez Mts. 



Ostrea sub/ecta, Conr. "May be the young of O. Panzana." 

 Sierra Monica. 



Ostrea Panzana, Conr. Panza, Estrella, and Gaviote Pass. 



Dosinia alta, Conr. Salinas River. 



Dosinia Innyida, Conr. Salinas River. 



Dosinia niontana, Conr. Salinas River. 



Dosinia suhohliqna, Conr. Salinas River. Also a small Venus, 

 a Xatica, and a Pecten. 



Mytilus Inezensis, Conr. Sta. Inez. 



Lutruri(( transmoiifana, Conr. Allied to L. impijria, Conr. 

 Los Angeles j also San Luis. 



81 



