I9I3] STRATIGRAPHY OF PACIFIC COAST OF AMERICA. 575 



far as known any recent species of mollusca while the number grad- 

 ually increases to about 6 per cent, of the fauna in the Monterey. 

 The proportion of species extending from the Monterey into the 

 Middle Pliocene is somewhat greater — perhaps 25 per cent. Two 

 or three long-lived species known in the Eocene range through the 

 entire Sooke-Monterey succession. With two notable exceptions, 

 the Sooke and Twin River formations, this entire succession is 

 decidedly subtropical in facies. There is a conspicuous element 

 of distinctly Eocene-Oligocene genera throughout, such as Crassitel- 

 Htes, Aturia, Molopophorus, Exilia, Perissola.v, Priscofnsus, Strep- 

 sidura, and giant Turritellas, associated with an exceptionally large 

 number of species of Turris, Patella, Barbatia, Macrocallista, Eudo- 

 lium, giant Limas, and other usually tropical genera unknown or of 

 exceptional occurrence in the later deposits of the district. 



This Oligocene facies of the fauna is very obvious in the Sooke 

 and Astoria, but less marked in the Vaqueros owing to the additional 

 presence of Lyropecten and giant Ostreas, typical Miocene types 

 which, however, must have had their beginning in earlier strata to 

 have become so widespread and important an element of the Mio- 

 cene fauna. The Monterey is faunally closely allied to these other 

 beds by numerous identical species, but as far as our present knowl- 

 edge goes, might be placed equally well in the latest Oligocene or 

 the earliest Miocene on the basis of the general faunal facies. 



The Sooke Formation. 

 Occupying several disconnected areas along the south coast of 

 Vancouver Island from Becher Bay westward to Sombrio River 

 near Port San Juan and perhaps farther, is a formation originally 

 described as probably upper Miocene owing to the boreal type of 

 fauna. This Merriam-* has termed the Sooke beds. With the ex- 

 ception of the type area between Muir and Coal Creeks several 

 miles west of Sooke where drillings have shown the sediments to 

 be more than 1,500 feet thick, the beds comprise only a few feet 

 of basal conglomerate usually less than the height of the sea cliffs 

 in thickness. These lie directly on the bedrock complex, the Van- 



-4 Bull. Dept. Geol. Univ. Cal., II., 1896, p. 101-8. 



PROC. AMER. PHIL. SOC, LH. 212 S, PRINTED NOV. "J, I9I3. 



