ON MOLLUSCA OP THE WEST COAST OF NORTH AMERICA. 589 



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

 They are divided into, I. " Eocene," and 11. " Miocene and Eecent Porina- 

 tions." 



I. Eocene (aU from Caiiada de las TJvas *). 



Cardium linteum, Oonr., n.s. Allied tp C Nieolleti, Oonr. - 



Dosinia alia, Conr., n.s. 



Meretrix Uvasana, Conr., n.s. 



Meretrix Californiana, Oonr., n.s. Allied to M.Pouhoni, Conr. 



Orassatella Uuasana, Conr., n.s. 



Crassatella alfii, Conr., n.s. In small fragments, hut abundant, 

 as at Claiborne, Al. 



Mi/Hlus humora-i, Conr., n.s. 



Cardita planicmtri, Lam., = Venericardia asoia, Rogers. First 

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

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

 can as of the European Eocene period. 



Natica ?a:tites, Conr., 1833. 



Natica fgibbosa, Lea, 1833, or N. semilunaia, Lea ; also found f.t 

 Claiborne, Al. 



Natica alveata, Conr., n.s. 



Tunitella Uoasana, Oonr., n. s. Allied to T. obnda, Conr.,= T. 

 lineata, Lea, from Claiborne, Al. 



Volutatithes [fVolutilithes] Californiana, Conr., n.s. llesembles 

 V. Sayana, Conr. 



?Busycon Blalei, Conr., n.s. a 



Clavatula Caliiornica, Conr., n.s. Allied to C. pronda, Conr., of 

 Claiborne Eocene. 



Miocene and Recent Formations (from various localities). 



Cardium mo-hstum, Conr., n.s. San Diego. [May be Hemicar- 

 dinm hiangidattim, jun.] 

 „ 19. 17. Nucula 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. 

 III. 16. 18. Corbula Diegoana, Conr., n.s. San Diego. 

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

 „ 27. 20. Meretrix decisa, Conr., n.s. Ocoya Creek. 



„ 22. 21. Meretrix Tularena, Conr., n.s., [in list, "Tularana" in textl 



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



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



14 18 I I '^^^^™"' eongesta. Conr., n.s. [Appears a JSeterodonax, allied to 



& 21 ( ^^' 1 iiniaculata, Lam.] Abundant at Monterey, Carmello, and San 



" ' ( Diego. 



„ 17. 24. Tellina Pedroana, Conr., n.s. [.''= T. gemma, Gld.] Recent 



formation. San Pedro. 

 „ 29. 25. Area microdonta, Oonr., 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, famished fifteen species. Of these, 

 three correspond 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 ;" whicli 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 the author expects that "when the rock shall have been disco- 

 vered and investigated in situ, fresh forms will be obtained, with which we are ah-eady 

 familiar in eastern localities." 



75 



