^913-] STRATIGRAPHY OF PACIFIC COAST OF AMERICA. 565 



upon indurated shales, sandstones, and conglomerates of supposed 

 Cretaceous age^^ and a great complex of metamorphic sandstone, 

 shale, radiolarian chert, glaucophane schist, and greenstones cut 

 by peridotite serpentine, a series closely resembling the Franciscan 

 of southern Oregon and the California Coast Ranges. 



In the Cascade Mountains of Oregon and southern Washington 

 the contacts between the tertiary and older rocks are usually ob- 

 scured by outpourings of lava but farther north RusselP^ has 

 described Alesozoic and older sediments associated with granite, 

 greenstones and serpentine. 



On Vancouver Island the Vancouver Series underlies the Oligo- 

 cene ; it is composed of slates, limestones, and greenstone-diorites of 

 supposed Carboniferous and perhaps also Triassic age, cut by bio- 

 tite granite. This has been described by George M. Dawson. ^^ 

 Farther north in the Straits of Georgia Chico rocks have a wide 

 distribution. 



Eocene Deposits — The Tejon Series. 



Eocene deposits form a large proportion and from an economic 

 standpoint the most important part of the Tertiary sediments of 

 western Oregon and Washington. These belong so far as known ex- 

 clusively to the Tejon Series. Everywhere that a contact has been 

 observed the Tejon lies directly on the pre-tertiary rocks, so it 

 appears that the Martinez formation (early Eocene) of California 

 is not represented on the north Pacific coast. In addition to being 

 the most widespread formation the Tejon is the most extensively 

 developed. Prevailing low dips render it impossible to study it 

 conveniently in any one section, but from data obtained in the coal 

 field of Pierce County, Washington, and several other partial sec- 

 tions it is probable that 15,000 feet is not too great an estimate of 

 the thickness of the series in western Washington, while in Oregon 

 at least 13.000 feet of. beds stratigraphically higher are present. This 



11 Arnold, R, Bull. Geol. Soc. Am., XVIIL, 1906, p. 459. 



12 "A Preliminary Paper on the Geology of the Cascade Mountains in 

 Northern Washington," 20th Ann. Rept. U. S. Geol. Sur. (II), 1900, p. 83-210. 



13 2d Ann. Rept. Geol. Sur. Can., 1887, p. 10B-13B. 



