490 / HARLEN BRETZ 



existence of marine Pleistocene deposits along Shoalwater Bay, 

 Washington, lo to 15 miles north of the mouth of Columbia River, 

 and fossiliferous beds below about 330 feet A.T. at the mouth of 

 Des Chutes River, an Oregon tributary entering the Columbia 

 immediately east of the Cascade Range. If the sediments in these 

 two localities, more than 150 miles distant from each other, were 

 deposited in the same body of water, then Willamette Valley of 

 western Oregon, intermediate in position, must have been largely 

 submerged. To this water body Condon gave the name of 

 Willamette Sound. He correlated it with the Champlain sub- 

 mergence on the Atlantic Coast. 



Static waters in the Columbia Valley east of the Cascade Range " 

 were postulated by T, W. S3rmons in a Senate document,^ pub- 

 lished in 1882, dealing chiefly with navigation of the Columbia. 

 Symons saw many rounded bowlders on the basalt plateau along 

 the Columbia in central Washington, he saw considerable tracts 

 of the basalt covered with sedimentary deposits, and he found 

 large, though fragmentary, gravel terraces in the Columbia Valley. 

 All of these he ascribed to a glacial lake which he named Lake 

 Lewis. He thought this lake extended southward as far as Walla 

 Walla and Wallula. He gave no altitudes, cited no evidence for 

 the Champlain age which he assumed for the submergence, and 

 suggested no cause for the ponding. 



I. C. Russell made a geological reconnaissance in central 

 Washington in 1892, and in his report^ revised Symons' data some- 

 what but adopted his conception of a glacial lake. His revision 

 consisted in eliminating the sedimentary formation exposed in 

 White Bluffs along the Columbia. This he considered to be a 

 portion of the John Day Series of Tertiary age. He also added the 

 valuable item that there were many foreign granite bowlders in 

 the Columbia and Yakima valleys which had been carried in bergs 

 to their present positions. Russell thought that a glacier might 

 have dammed Columbia River at The Dalles, just below the mouth 

 of Des Chutes River, but he admitted the possibility of subsidence 



'"The Upper Columbia River and the Great Plain of the Columbia," Senate 

 Document No. 186, Forty-seventh Congress, ist sess., Washington, 1882. 



^^ "A Geological Reconnaissance in Central Washington," U.S. Geol. Surv.^ 

 Bull. 108 (1893). 



