68 CALIFORNIA ACADKMV OF Kl'IENCES. 



Amcrienn species, Lncinn ntnitUiucntn, Ci/lichiia itlbu, and Puden cnurinns. There 

 lire luaiiy such cases of the simihirity of species, ami in a few instances identical 

 species have been found which are common fo the two regions. The following species 

 are fonnd in Hr. Hnuins' list of upper Tertiary fossils from Ojai, near ToUin, which 

 are also fouml in the Saii Pcflro deposits: 



List of Fossils fkom O.iai, wiikii aiuc Founh in xnK San Piinuo Dicposits. 



Cardiiim eolifomiente [^ C. rorliin] Krilht xuhorhieuhirh J'anopia rjtniro»a 



Crrfiiduln nriilriiln Macomii mixiilfi Tnnux nullnlli 



Among the species now fonnd living in Japan, and on the west American 

 coast, anil also fonnd in the San Pedro deposits, are the following:' 



List ok Livinq Species Common to Japan and the West Coast of North America, 

 WHICH akk Found in the San PiCDito Deposits. 



Cardium rorhio Macoma naniila SurKjuinolaria nuUalU 



Crfpiduln ijrandin Macoma srcta Siphonnlia kelli'tlii 



Cryplorhiton itUUtri Mylilus rdutis Trcmis nuttalli 



Drnlntium h'xaijonum Natica clauita Tapes slaminea 



Drillia iiiTmu PecO-n herlcfus TcUina bodegcnuh 



Lrplothyra carpenter! Purpura crixpala Trilonium ( ^= Prifne ) oregonrnniit 



Macoma rdulU Panopea generosa Trophon orphi'iix (= T . atuarli (^.) ) 



Macoma inquinala Pododeamua macroschisma 



The living fannas of the Japanese and west American coasts, thongh having 

 many species in common, are not as closely related as are the upper Tertiary and 

 Pleistocene faunas of the same regions. This has been brought about in two ways. 

 First, the more or less close connection between the two regions, which existed in 

 late Tertiary and early Pleistocene times, has been l)roken; and second, southern 

 species from the warm China seas have migrated northward and mingled with the 

 Japanese early Pleistocene species, while Panama species have come northward 

 during the upper San Pedro time and changed the aspect of the fauna of the west coast 

 of North America. Those species which Japan and the west coast of North America 

 have in common are either circumboreal or are forms which have changed little since 

 the habitats of the two faunas were similar and connected; those species which differ 

 but slightly have in many cases made this change since the connection was broken; 

 and many of the forms which occur in each fauna, and which have no counterpart in 

 the other, have come into these faunas in comparatively recent times. 



An interesting example of the migration which took place between Japan and 

 western North America is offered by the genus Halioth. This genus is of Asiatic 

 origin, but it migrated to the northern American coast during late Pliocene or early 

 Pleistocene times. This is shown by the absence of this species from any of the pre- 

 Pleistoceue formations along this coast. Only two fossil Halioiidai have been found 

 on this coast, one being taken from the upper San Pedro (Pleistocene) gravel of 



> TbU lint Is compiled from tb* followliii! papers : 

 Molluaks of Weitern North America. By P. P. C&rpenler. Smllheonlan Miscellaneous Collectioas, No. 252, 1872. 

 CaUlogae of Csllforals Fossils. B; J. O. Cooper. Ttb Aon. Kept. Cal. SUte Mineralogist, 1888. 



