The Willamette Sound. 61 



In all this we are obviously studying only 

 the lower limit of this latest of Oregon's geo- 

 logical changes. Where shall we look for 

 its upper limit? In other words, how high 

 did those waters rise above the present sea 

 level? We might look for traces of its upper 

 reaches in the remains of old sea beaches- in 

 elevated places on the abrupt slopes of the 

 hills along the coast, but in such exposures 

 old beach lines are but rarely preserved 

 against the storms of a thousand winters, still 

 less against those of tens of thousands. To 

 find them and their records plainly legible we 

 must look to more sheltered localities inland. 

 It will help us a good deal in our search for 

 such shore lines of the interior to carry with 

 us a theory that will point out the possible 

 limits within which they may reasonably be 

 sought. Will the facts we have gathered from 

 Shoalwater bay and the lower Columbia war- 

 rant us in forming such a theory? Let us see. 



Stratified sediment of a hundred feet in 

 vertical thickness finer far in its upper lay- 

 ers than in those lower, and in its upper layers 



