144 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Sek. 



est beds may belong to the age of the Etchegoin-Jacalitos fauna 

 of middle California. 



The Wildcat fauna belongs to the Puget Sound province, 

 which then extended southward to Cape Mendocino, as it does 

 now, and indicates a temperature of about 50° F. min. It lacks 

 all the southern, warm- water, types, such as giant Area, 

 Dosinia, Chione gnidia group, Janira, Pecten healeyi, Pecten 

 oweni, Lyropecten. It was the southern limit of the northern 

 forms: Macoma calcarea, Pecten caurinus, Pecten dilleri, 

 Natica clausa, Buccinum, Haliotis and Volutopsius. It is 

 especially characterized by the large number of giant Chryso- 

 domus, and by the first appearance of the oriental Haliotis in 

 the California waters. 



Cape Mendocino played the part, which now falls to Pt. Con- 

 ception, as the dividing line between the warm-water and the 

 cold-water faunas. This was the time of greatest differentiation 

 of climatic zones on the Californian coast. The cold-water zone 

 extended down to Cape Mendocino, and the warm-temperate 

 zone pressed northward nearly to the same place. There was 

 thus some telescoping of the isotherms, with the middle Cali- 

 fornian province obliterated. This fact has made difficult the 

 correlation of the Pliocene of northern California with that of 

 the southern part of the state, and has resulted in faunas of the 

 same age having been assigned to very different parts of the 

 geologic column. 



Merced (San Francisco Peninsula, south of San Francisco, 

 lat. 37° 30' N.). 



Collections by W. M. Gabb, G. H. Ashley, B. Martin, H. 

 Hannibal, and many others have yielded : Area trilineata Con., 

 Cardium meekanum Gabb, Cardium qiiadrigenarium Con., 

 Chione securis Shum., Marcia gibbosa Gabb, Mya japonica Jay, 

 Pandora grandis Dall, Paphia staleyi Gabb, Phacoides annu- 

 latus Rv., Saxidomus giganteus Desh., Schizothoerus pajaro- 

 anus Con., Spisula albaria Con., Zirphcea gabbi Tryon, Chryso- 

 domus stantoni Am., Chrysodomus (tabulatus) var. colmaensis 

 Martin, Crepidula princeps Con., Nassa moraniana Martin, 

 Natica clausa B. & S., Pisania fortis Carp., Dendraster inter- 

 Jineatus Stimp. 



This fauna is more northern in character than the underlying 

 Purisima, agreeing more nearly in character with the older and 



