GLACIAL WORK IN WESTERN MOUNTAINS 721 



13. The high-level quartzite gravels on the plains east of the 

 mountains are believed to be deposits made by streams at the 

 close of the first epoch of base-leveling recorded in the present 

 topography. 



14. The strata at the mouth of Sun River and Muddy Creek 

 canyons contain fossils of Carboniferous age. Rocks of the same 

 age prevail in the whole of the eastern face of the mountains, 

 where their thickness is several thousand feet. 



Some other scattering data were collected touching the gen- 

 eral geology of the region studied. 



BETWEEN THE ROCKIES AND THE CASCADES IN NORTHWESTERN 

 MONTANA, NORTHERN IDAHO, AND EASTERN WASHINGTON 



Messrs. George H. Garrey and Eliot Blackwelder spent most 

 of August and September in the study of glacial phenomena 

 in northwestern Montana, northern Idaho, and northeastern 

 Washington, most of the time being spent in the latter state, 

 between Chelan Falls and Newport. The moraine of the ice 

 lobe which came south through the Okanogan Valley, loops 

 southeastward from Chelan Falls to a point about six miles west 

 of Coulee City, where it bends northeastward to a point five 

 miles north of the city, on the bluff of the Grand Coulee. 

 Morainic material not aggregated into a marked terminal 

 moraine, continues northward along the entire western rim of 

 the Coulee. During glacial times the ice probably blocked the 

 Columbia at its junction with the Grand Coulee, forcing the 

 waters of the Columbia down the Coulee, as has been suggested 

 by Russell and others. That glacial drainage followed the 

 course indicated is suggested by the fact that the terraces of the 

 Columbia above the Coulee are continuous with terraces in the 

 Coulee. 



Northeast of the junction of the Grand Coulee with the 

 Columbia, the moraine of the Okanogan or Coulee City lobe 

 takes the form of a well-developed ridge which, at a point about 

 five miles north of the junction of the Columbia and the Grand 

 Coulee, the most northerly point where it was seen, was trending 



