lOO WARREN DUPRE SMITH AND EARL L. PACKARD 



separated and heterogeneous materials in their proper chronological 

 order. 



At many points along the Oregon coast, but especially well 

 developed at Cape Blanco, we find marine conglomerates, sands, and 

 shell beds lying unconformably above the Empire (Pliocene) and 

 nearly horizontal, but with a slight southerly dip. The section at 

 Cape Blanco is described and figured by Diller.^ 



There are two distinct horizons above the Empire here, the 

 lower one being presumably the Cape Blanco beds of Diller which 

 Dall has suggested may correspond to the Merced of California 

 and hence Pliocene. The upper part with recent-looking shells is 

 Pleistocene, without much doubt. These have been called the 

 Elk River beds, which Arnold and HannibaP correlate with the 

 Saanich formation of Puget Sound. These investigators do not 

 appear to make any separation of the beds overlying the Empire. 



Diller notes a lithologic difference between the Blanco and the 

 Elk River beds, chiefly in the matter of consistency. This may be 

 of little significance. Similar Pleistocene marine deposits can be 

 seen in similar position all along the Oregon coast to the Columbia 

 River. 



From a consideration of the above-mentioned deposits we are 

 led to discuss the Satsop formation of Bretz,^ in which this investi- 

 gator includes some at least of these coastal gravels. His type 

 locality for this formation is in the Chehalis Valley, Washington, 

 and the formation is especially well represented in Oregon along the 

 Sandy, a tributary of the Columbia River, near Portland. Bretz's 

 description of this formation along the Sandy is as follows : 



The formation is at least 600 feet thick along the Sandy River, with the 

 base below river-level. The material is stream-bedded gravel and sand, 

 indurated in some places to a conglomerate and sandstone. Quartzite is a 

 common constituent for 10 miles south of the Columbia, but has not been found 

 more than 15 miles from the master-stream. Quartzite and basalt are the 

 most important constituents. 



The Satsop formation of the lower Willamette Valley is maturely dissected, 

 the dissection adjusted to a base-level 200 feet or more above present flood 



'J. S. Diller, U.S. Geol. Sun., Bull. ig6, p. 31. 

 ^ R. Arnold and H. Hannibal, op. cit., LII, 508. 

 3 J H. Bretz, Jour. Geol., XXV, No. 5 (1917), 446-59. 



