ON MOLLUSCA OF THE WEST COAST OF NORTH AMERICA. 589 



'Appendix to the Preliminary Geological Report,' 8vo, Washington, 1855. 

 They are divided into, I. " Eocene,"' and II. " Miocene and Kecent Eornia- 

 tions." 



I. Eocene (all from Canada de las TJvas *). 



Cardium linteum, Conr., n.s. Allied to C. Nicolleti, Conr. 



Dosinia nUa, Conr., n.s. 



Meretrix Uvnsann, Conr., n.s. 



Meretiix Califnrniana, Conr., n.s. Allied to M.PouIsom, Conr. 



Crasnafelln Ucasnna, Conr., n.s. 



CrassaUdlii alta, Conr., n.s. In small fragments, but abundant, 

 as at Claiborne, Al. 



3It//iliis hi/uwrif^, Conr., n.s. 



Cardita planicosta, Lam., = Ycnericardia ascia, Rogers. First 

 discovered in Maryland in 1829, by Conr. ; occurs abundantly 

 in Md., Va., Al., and is quite as characteristic of the Ameri- 

 can as of the European Eocene period. 



Kntica ?a'tites, Conr., 1833. 



Na'ica ?</ibbosa, Lea, 1833, or N. semilunata, Lea ; also found at 

 Claiborne, Al. 



Katica ah-cafn, Conr., n.s. 



TurritcUn Unimna. Conr., n. s. Allied to T. ohrida, Conr.,:=7'. 

 lineafft, Lea, from Claiborne, Al. 



Volutatithes [?Volutilithes\ Calif 07'niana, Conr., n.a. Resembles 

 V. Sni/ana, Conr. 



?Bus\/c(»i B'akei, Conr., n.s. 



Clavntula CaW'ornica, Conr., n.s. Allied to C. pronda, Conr., of 

 Claiborne Eocene. 



Miocene and Recent Formations (from various localities). 



m. 15. IG. Cardimn molesium, Conr., n.s. San Diego. [May be Hemicar- 

 di>i»i hiangidfdicm, jun.] 

 „ 19. 17. Niicula decisa, Conr., n.s. Resembles N. divaricata of the Ore- 

 gon Miocene. [Closely allied to N. castrensis, &c., but too im- 

 perfect to determine.] San Diego, 

 m. 16. 18. Corbida Diefjoana, Conr., n.s. San Diego. 

 „ 20. 19. Meretrix imiomeris, Conr., n.s. Monterey Co. 

 „ 27. 20. 3Ieretrix decisa, Conr., n.s. Ocoya Creek. 



„ 22. 21. 3Ierefrix Tidarna, Conr., n.s., [in list, "Tidarana" in text]. 



From a boulder in Tulare Valley. [Comp. Tapes gracilis, Gld.] 



„ 28. 22. Tellina Dicgoana, Conr., n.s., San Diego. 



14 1ft i I ^''^^'"^' cf>i>gestn. Conr., n.s. [Appears a Heterodonax^ allied to 



& 21 ( ~'^" 1 liimaculata, Lam.] Abmidant at Monterey, Carmello, and San 



*' ' ( Diego. 



„ 17. 24. Tellina Pedraana, Conr., n.s. [?= T. gemma^ Gld.] Recent 



formation. San Pedro. 

 „ 29. 25. Aral microdonta, Conr., n.s. Resembles A. arata, Say, of the 

 Maryland Miocene. Miocene, ? Tulare Valley. 



• The existence of Eocene strata on the Pacific slope is ascertained by a single boulder 

 of very hard sandstone, which, though very small, furnished fifteen species. Of these, 

 thi'ee con-espond with forms from Claiborne, Alabama ; and the " finger-post of the 

 Eocene" appears in its usual abundance. Mr. Conrad characterizes the specimens as 

 " beautifully perfect ;" wliicli would not have been supposed from his descriptions and 

 figures. They " seem to indicate a connexion of the Atlantic and Pacific Oceans during 

 the Eocene period ;" and tlie author expects that "when the rock shall have been disco- 

 vered and mvobtigated in si/u, livsh forms will be obtained, with which we are ah'cady 

 familiar iu eastern localities." 



75 



