15 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Seb. 



mation to rest upon their upper or Olequah formation. Their 

 evidence for two divisions here seems to have been based in 

 part upon the evidence of fossil floras. An examination of 

 the faunas obtained at various intervals from the base of sec- 

 tion at Olequah to near the top at Winlock shows very little 

 difference in their composition. It is true that near the middle 

 of the section brackish and fresh water beds appear, but the 

 marine faunas below and above are very similar. A compari- 

 son of the faunas occurring in the Eocene strata of the Cowlitz 

 River area with those which have been listed and described 

 from the tj'^pe Tejon in southern California leads the writer to 

 the same conclusions as have been stated by Dr. Dickerson, 

 namely, that the Tejon of the Cowlitz River area is the equiva- 

 lent of the middle zone in California as represented in the 

 Mount Diablo region. 



CONDITIONS OF DEPOSITION 



The Eocene of western Washington is widely distributed. 

 It extends well up into the western portions of the Cascade 

 Mountains and may even possibly connect beneath a thick cov- 

 ering of Miocene lavas with the Eocene deposits on the east- 

 ern slopes of the mountains. The Eocene deposits involved 

 within the western slopes of the Cascades are almost entirely 

 of brackish or fresh water origin. No marine strata are known 

 to be interbedded. In the Puget Sound Basin, brackish water 

 deposits predominate, but in southwestern Washington great 

 thicknesses of marine deposits are interbedded. During the 

 upper Eocene the larger part of southwestern Washington and 

 a portion of the Puget Sound Basin appear to have been an 

 embayment of the ocean. The present site of the western slopes 

 of the Cascade Mountains seems to have been in part occupied 

 by large estuaries. During Tejon time diastrophic movements 

 were differentially acting upon the entire western portion of 

 the state, causing fluctuations in the depth of water in the 

 embayments and estuaries and a shifting of the shorelines. 

 These oscillations are recorded in the interbedded character of 

 the marine and brackish water sediments. The eastern shore- 

 line of the southwestern Washington embayment appears to 

 have existed at times along the present site of the Northern 



