PROBLEM OF WILLAMETTE SOUND
BY IRA S. ALLISON
Condon based his theory of a Willamette Sound in Willamette Valley, Oregon, upon a proposed correlation of its valley fill with a marine terrace at Shoalwater Bay (north of the mouth of Columbia River), with a Columbia River terrace near Astoria, Oregon, and with certain sediments in valleys tributary to Columbia River near The Dalles, Oregon. Discovery of erratic glacial boulders, requiring transportation by icebergs floating in deep water, later added more substantial evidence of such a sound. On the other hand, the absence of shoreline markings, the lack of marine fossils in the valleys, the lack of well-formed marginal deltas, and the presence of mammalian fossils in the valley fill have left doubt on the theory.
The present paper attempts to evaluate and to reconcile these inconsistent lines of evidence. In spite of difficulties, such a sound appears to furnish the . . .