BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 23, pp. 517-536, PL. 33 OCTOBER 22, 1912 



SOME TEETIARY AND QUATERNARY GEOLOGY OF WEST- 

 ERN MONTANA, NORTHERN IDAHO, AND 

 EASTERN WASHINGTON ^ 



BY OSCAR H. HERSHEY 



(Presented in abstract before the Society Apnl 1, 1911) 



CONTENTS 



Page 



Glaciation in Deer Creek Valley, Montana 517 



Glaciation in the Coeur d'Alene district, Idaho 518 



Kellogg system of river terraces 519 



In general 519 



Modern alluvium 519 



Thirty-foot terrace 519 



Sixty-foot terrace 520 



Two-hundred-foot terrace 521 



Six-hundred-foot terrace 522 



Eleven-hundred-and-fif ty-f oot terrace 523 



Terraces east of Kellogg region 524 



Terraces west of Kellogg region 525 



Early glaciation in northern Idaho 530 



Origin and age of Coeur d'Alene Lake 531 



Valleys of Clearwater country, Idaho 532 



Plains and valleys of eastern Washington 533 



Summary 535 



Glaciation in Deer Creek Valley, Montana 



The valley of Deer Creek is a deep, heavily timbered gulch heading at 

 about 7,000 feet of altitude in the Bitter Root Range and extending 

 about 7 miles to the Saint Regis River near Deborgia, Missoula County, 

 Montana. Streams of ice flowing from the Chief, Diamond, Crj^stal, 

 and other cirques, two of which contain typical moraine-dammed glacial 

 lakelets, coalesced in the main valley into a glacier that during an earlier 

 stage extended almost to the mouth. It ground the Belt quartzites and 

 preglacial gravels into a ground moraine of light-colored clay, with 



1 Manuscript received by the Secretary of tlie Society December 6, 1911. 



(517) 



