CHAPTER 11. 



GEOLOGY OF THE WIKD EIYEE RANGE Am) COUNTRY 



EASTWARD. 



WIND RIVER RANGE. 



As a portion of the Rocky Mountain system, tlie Wind River Range 

 occupies an important position. Separating tlie drainages of large riv- 

 ers, and forming, as it does, tlie continental divide for some distance, it is 

 one of the key-points to the proi)er interpretation of our early geographi- 

 cal evolution. No question, perhaps, pertaining to the broad views en- 

 gendered by the accumulating knowledge of our West, is more important, 

 more fraught with interest, than that bearing upon the geological age of 

 the Rocky Mountains. Until the entire system is fully known, until the 

 results of careful explorations are available, we are forced to base our 

 hy[)otheses upon this subject on disconnected, necessarily incomplete, 

 evidence. Few of the ranges composing the central chain of the Rocky 

 Mountains afford so remunerative a field for study as that of the Wind 

 River. 



Within the range proper the geological and geonostic features are 

 simple, but the eastern base shows arrangements and disturbances that 

 would require months, rather than days, fully to be worked out. 



STRUCTURE OF THE RANGE. 



While discussing, in previous pages, the topography of our district, 

 the physical appearance of the Wind River Range has been touched 

 upon. It will be remembered that it can appropriately be divided into 

 three chains. Of these the main or western chain comprises the most 

 elevated points and forms the divide ; the second is composed of the 

 foot-hills, and the third is made up by the outlying hills along the base 

 of the second. During Fremont's first expedition he traveled along the 

 western base of the range, from its southern termination to Fremont's 

 Peak. His course lay, essentially, between the mountains proper and 

 that which has above been designated as the western subsidiary range. 

 His descrii3tion of what he terms the "central chain" is very gTaphic 

 and, so far as he has seen it, correct. As the most prominent southern 

 point of the range we must regard Stambaugh Peak. Rising to an ab- 

 solute elevation of 12,700 feet, its sharply-cut form and weU defined 

 ridges mark it as an important feature in the landscape. From there 

 northward we find that the main chain is marked by peaks of nearly 

 uniform height, reaching about 13,000 feet. Within the limits of our dis- 

 trict two points rise considerably above this general summit-niveau : 

 Snow Peak, 13,400 feet high, and Temple Peak. In cross-section this 

 western chain might appropriately be compared to a single saw-tooth. 

 Falling off comparatively gently toward the west, its eastern slope is one 

 of remarkable declivity. So high, indeed, is the angle of this slope that 

 64 



