138 CALIFORNIA ACADEMY OF SCIENCES [P«oc. 4th Se«. 



five per cent of the fauna to have become extinct entirely, for 

 all the tropical Mexican and Panama species to die out locally, 

 and for the general temperature to be lowered by about 4° F. ; 

 also long enough for a considerable amount of deformation, ter- 

 racing, and erosion to have taken place. 



San Francisco Peninsula, lat. 37° 30' N. The Pleistocene 

 deposits of Seven Mile Beach, near San Francisco, contain a 

 fauna very like that now living in the same region, with the 

 exception of Natica clausa, which is not known south of Puget 

 Sound. Further collecting would probably yield more northern 

 species. 



Elk River, Cape Blanco (southwest Oregon, lat. 42° 50' 

 N.), In the raised beach are found : Kennerleya grandis Midd., 

 Macoma middefidorfii Dall, Mya truncata L., Pecten caurinus 

 Gld., Saxidomus giganteus Desh., Spisula voyi Gabb, Veneri- 

 cardia ventricosa Gld., Amphissa corrugata Hds., Argobuc- 

 cinum oregonense Redf., Bela harpa Dall, Bela tabulata Carp., 

 Boreotrophon gracilis Perry, Boreotrophon stuarti Smith, Buc- 

 cinum strigillatnm Dall, Chrysodomus phoeniceus Dall, Chryso- 

 domus tabulatus Baird, Epitonium hindsi Carp., Natica clausa 

 B. & S., Purpura foliata Gmel., Sipho halibrectus Dall, Solari- 

 ella cidaris Adams, Trichotropis cancellata Hds., Tritonofusus 

 rectirostris Dall, Turris perversa Gabb, (all northern or Puget 

 Sound species), along with a considerable number of forms 

 now living on the Oregon coast. This fauna indicates a tem- 

 perature considerably lower than that now prevailing at Cape 

 Blanco, and thus probably belongs to the lower San Pedro. 



Arnold and Hannibal^ assign the Cape Blanco beds to the 

 upper Pliocene, but the fauna listed by them is a mixture of 

 Pliocene and Quaternary. Dall's interpretation of the geology 

 of Cape Blanco* was partly correct. 



Vancouver Island (near Victoria, lat. 48° 30' N.). Astarte 

 alaskensis Dall, Cardium comoxense Dall, Cardium decor atum 

 Grew., Leda fossa Baird, Macoma calcarea Gmel., Macoma 

 krausei Dall, Mya truncata L., Pecten islandicus Miiller, Saxi- 

 cava arctica L., Serripes groenlandicus Gmel., Natica clausa 

 B. & S., Natica pallida B. & S. 



• Marine Tertiary Stratigraphy of the North Pacific Coast of America. <Proc. 

 Amer. Phil. Soc. Vol. 52, No. 212, 1913, p. S9S. 

 •Bull. 196, U. S. Geol. Survey, (1902), p. 31. 



