PLEISTOCENE SUBMERGENCE IN COLUMBIA VALLEY 491 



allowing "the ocean to enter the great central valley between the 

 Cascades and Rocky mountains." 



J. S. Diller published his geological reconnaissance of north- 

 western Oregon^ two years after the appearance of Russell's report. 

 In it he adopted Condon's notion of a Willamette Sound. Like 

 Russell, he announced the existence of foreign bowlders in the 

 valley and interpreted these as berg-carried in the waters of a 

 Pleistocene submergence. 



Russell, in another paper, published in 1898,^ stated his belief 

 that the Great Terrace in the Columbia Valley, between the 

 junction of the Methow and Chelan valleys, was a delta built in 

 Lake Lewis. He considered that the termination of the Great 

 Terrace, a httle below the mouth of Chelan River, was the delta 

 front. Russell noted here that "full and unquestionable evidence 

 of its [the lake's] actual existence cannot be said to have been 

 discovered." 



CRITICAL EXAMINATION OF THE DATA PRESENTED BY THE FORE- 

 GOING WRITERS 



Shoalwater Bay. — These deposits, cited by Condon, are unques- 

 tionably part of the coastal phase of the Satsop formation.^ This 

 formation is largely a river gravel in the Columbia Valley, and 

 only along the coast was it deposited in standing water. In the 

 Shoalwater Bay (Willapa Bay) exposures there is abundant evidence 

 in the presence of gravel strata containing granite, gneiss, and 

 much quartzite that a vigorous current existed throughout the 

 length of the Columbia in Oregon and Washington when these beds 

 were deposited. Though the Satsop is believed from paleonto- 

 logical evidence to be Quaternary in age, it was laid down before 

 the present Cascade Range was folded and therefore long antedates 

 the Champlain epoch. The strata along Shoalwater Bay therefore 

 do not record a Willamette Sound. 



^"A Geological Reconnaissance in Northwestern Oregon," U.S. Geol. Surv., 

 17th Ann. RepL, Part I (1895). 



2 "The Great Terrace of the Columbia," Amer. Geologist, XXII (1898), 363. 



3 J H. Bretz, "The Satsop Formation of Oregon and Washington," Jour. Geol., 

 XXV(i9i7),447. 



