136 PROCEEDINGS OF THE CORDIT^LERAN SECTION 



Discussion 



Professor Louderback asked to have explained the relation between the 

 northwest-southeast axes of folding and the Cascade uplift, in particular 

 whether they might not correspond to pre-Sierran deformation and Sierran 

 faulting in the Oalifurnia region. The author replied tliat lie believed they 

 were formed cuntemporaueously and as parts of the same general movement. 



EOCENE OP THE COWLITZ VALLEY, WASHINGTON 

 BY CHARLES E. WEAVER 



{Abst7'act) 



The Eocene of Washington is extensively developed in that portion of the 

 Cowlitz Valley situated in Lewis and Cowlitz counties. From the town of 

 Wiuloek southward to Castle Rock there is a series of interbedded marine, 

 brackish water and fresh water sediments having a thickness of at least 8,000 

 feet. These strata have a northwest to southeast strike, with a low dip to the 

 northeast. In the lower portion of the series numerous layers of basaltic lava 

 and tuff are intercalated. About one mile north of Vader a minor local fold 

 has been developed on the northeasterly pitching flank of the series. On the 

 basis of marine faunas, no distinction can be made between the upper and 

 lower portion of the formation. The fauna is typically Tejon. 



Presented without notes and illustrated by diagrams and maps. 



Discussion 



Doctor Branner expressed his approval of the fact that the author used the 

 engineer's methods of determining the relative positions of the outcrops studied 

 instead of relying on maps that could not be depended on. 



RELATION OF THE TERTIARY QEOLOGICAL SCALE OF THE GREAT BASIN TO 

 THAT OF THE PACIFIC COAST MARGINAL PROVINCE 



BY J. C. MERRIAM 



[Ahsti-act) 



Although we are acquainted with the nearly complete series of geological 

 formations on both sides of the Sierra Cascade Range, there are very few 

 places at which any definite connection between the two sets of deposits has 

 been recognized. A satisfactory interpretation of West American Geology 

 must include reasonably certain determination of the time relations between 

 tlie Great Basin and the marginal marine provinces. 



Correlation between the two regions is based partly on lithologic evidence, 

 partly on the study of crustal movements and on the evidence of paleontology. 

 The paleontologic materials used in these correlations up to the present time 

 have been almost exclusively plant remains. Very recently remains of land 

 vertebrates found in the marginal marine province have offered an exceptional 

 opportunity for correlation. 



