70 GLACIAL AND SIJEFACE GEOLOGY OF THE PACIFIC COAST. 



in which they ai'e found ; in other words, these superficial deposits are en- 

 tirely made up of the materials disintegrated from the rocks in the vicinity." * 



"We have, in the paragraph above quoted, only indirect evidence as to 

 the former existence of glaciers in a part of the elevated region higli up 

 on the- Yellowstone River near the parallel of 44°. The important point, 

 liowever, in regard to which the evidence is direct, is, that the detrital ma- 

 terial, with which the slopes of the ranges in that region are covered, is all 

 of local origin, as is the case in every other part of the Cordilleras of which 

 mention has been made in the preceding pages. 



Although nothing is said in the Eeport from which the quotation given 

 above was taken about the existence of former glaciers in the region of 

 the Yellowstone Park, the following may be accepted as a strong indica- 

 tion that morainic accumulations of detrital material were intended to be 

 described. In his account of his explorations along the ridge, " in the more 

 immediate valley of the Yellowstone, near the entrance of the East Fork," 

 and not for from the lower end of the Grand Caiion, Dr. Hayden remarks as 

 follows: " Wiuxt were the forces that wrenched from the parent bed masses 

 of granite, from one ton to five himdred tons weight, rounded off the angles, 

 and lodged them upon the plains 300 to 500 feet above the channels of the 

 principal streams ? Along the East Fork, for twenty miles above its mouth, 

 on the west side, there is a sort of terrace [a moraine?] about a mile in 

 width, literally covered with the granite boulders which have been swept 

 down the valley from a sliort distance above." t 



In 1872 the Yellowstone region was again visited by Dr. Ilayden's 

 exploring parties, and the Teton Range examined and reported on by 

 Mr. F. H. Bradley, t This range, in whicli there is a group of three lofty 

 and jagged summits know^n as the Tetons, lies between the parallels of 43^ 

 SO' and 4i\ running nearly north and south along the west side of the head 

 of Snake River. The height of its culminating summit, Moxnit Hayden, is 

 stated at 13,858 feet. The valley at its base is a little less than 7,000 feet 

 in elevation (mouth of Lewis Fork, 6,870 feet; Jackson's Lake, 6,806 feet). 

 The principal cafions of this range appear, from Mr. Bradley's descriptions, 

 to have been formerly occupied by extensive glaciers. Great moraines are 



* Geological Survey of Montana and Adjacent Territories, 1871, p. 55. 

 t 1. c, p. 77. 



J Deport of the U. S. Geological Survey of Montana, Idaho, etc., 1S72, pp. 190-271. This appears to be the 

 first Report of Dr. Hayden's in which the words "glacier " and " moraine " occur. 



