492 / HARLEN BRETZ 



Des Chutes terrace. — Condon gave no list of fossils from the 

 terrace deposit. He simply said the material was stratified clays, 

 sands, and gravels containing tusks, teeth, and bones "of the land 

 animals of that period, marking at once the height at which these 

 waters stood." No one has since studied the fauna from this 

 locality. There are many Tertiary formations, with vertebrate 

 faunas, in Oregon and Washington in the great lava plain east of 

 the Cascades. The terrace may be the outcropping edge of a 

 formation of this kind, and not a remnant of a post- valley filling. 

 The feature, so far as known, gives no positive evidence for the 

 existence of Willamette Sound. 



The Dalles, Oregon. — Condon mentioned sediments deposited 

 in ravines cut in The Dalles beds at this place and ascribed them 

 to Willamette Sound. 



Swan Island, Portland. — Quoting Condon: "Currents of such 

 a vast body of water [Willamette Sound] .... the agency com- 

 petent to the heaping up of that long sandy ridge, loo feet high, 

 through which the river has cut at Swan Island, north of Portland." 

 This ridge is a terrace remnant; left by erosion, not deposition; 

 and is a portion of a great delta of the Columbia built in Willamette 

 Valley. Static waters stood no higher than its surface (300 

 feet A.T.) when the delta was built. If related to Willamette 

 Sound it is probably a record of the subsiding stages. It will be 

 discussed more fully later in this paper. 



White Bluffs (Ringgold formation) , Washington. — Merriam and 

 Buwalda recently have shown^ that the sedimentary formation 

 exposed in White Bluffs is of very late Cenozoic age, probably 

 Pleistocene. They favor the view that it is a flood-plain deposit, 

 and not lacustral. Its summit plane is considerably below the 

 upper limit of drifted erratics, and on this point it cannot be ruled 

 out of the list of phenomena bearing on the Columbia submergence 

 that we are discussing. But it rises 300 feet higher than the broad 

 gravel terraces on the opposite side of the river, and these are very 

 probably deposits of the river immediately following the Champlain 

 submergence. Merriam and Buwalda found no bowlders of any 



' "Age of Strata Referred to the Ellensburg Formation in the White Bluffs of the 

 Columbia River," University of California, Dept. Geol. Bull., X (191 7), 255. 



