68 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST. 



of this range exhibit well-marked evidences of glacial action. The summits 

 of the main peaks are everywhere Avorn in a manner which shows unmis- 

 takable signs of ice-erosion, and glacial boulders and detrital matter cover 

 the lesser depressions and slopes. In the region of Medicine Peak (height 

 12,231 feet), glaciers occupied all the upper valleys. The lowest elevation 

 reached by these is not expressly stated by Mr. Hague. Near the parallel 

 of 41° the range has its maximum width of twenty-five miles, and there 

 two well-defined ridges are developed, the culminating points of which 

 are Clark's Peak (13,167 feet) and Medicine Peak (12,231 feet). Between 

 these is a high plateau, nearly 10,000 feet above the sea-level, which is said 

 to be gently undulating, and without any marked topographical features. 

 It may, therefore, be inferred that the glaciers did not extend down as 

 low as this. 



In the Park Range, also, of which the highest summits reach an altitude 

 of a little over 12,000 feet (Mount Zirkel, 12,426 feet, Ethel Peak, 11,976 

 feet), the traces of former glacial action are abundant " through most of the 

 higher mountain regions." Mr. Hague notices a fact, which has also fre- 

 quently impressed itself on the attention of the writer, namely, the great 

 size of the terminal moraines as compared with the length of the glacier 

 itself In speaking of the Park Range, he remarks : '' These valleys are 

 never more than three or four miles in length, and at their mouth, consid- 

 ering the limited size of the ancient glaciers, are found immense terminal 

 moraines, which have undergone but little erosion in post-glacial times. It 

 is as if the entire former contents of the canon had been carried down and 

 dumped at the entrance, and had never been disturbed." 



In following the Rocky Mountain ranges to the north of the parallel of 

 42°, in order to make out the character and extent of the former glaciated 

 areas, great difficulties are encountered, as already mentioned, from the want 

 of any satisfactory detailed investigations in that region. The work of the 

 four United States Surveys * has almost exclusively been confined to the 

 southern and southern central portion of the Cordilleras, considerable areas 

 of which have been gone over by two or even three different organizations. 

 An exception to this, however, is foiuid in the case of the Yellowstone Park and 

 vicinity, whose picturesque scenery and most interesting geological features 



* The U. S. Geographical and Geological Survey, under Dr. F. V. Hayden ; the Fortieth Parallel Survey, 

 under Clarence King ; the Wheeler Survey, under the special auspices of the U. S. Engineer Department ; and, 

 finally, the so-called Powell Survey, the publications of which have been chiefly ethnographic in character. 



