GLACIAL WORK IN WESTERN MOUNTAINS 725 



accompanied and assisted by William Peterson, M. J. Averett, 

 H. B. Atwood, and Arthur Church. 



The portion of the Wasatch Mountains studied lies between 

 the parallels of 40^ 15' and 41°. The maximum width of the 

 range in this latitude is about twenty miles. The total area 

 examined for glacial phenomena was about lOOO square miles. 



Within this area, the positions of fifty Pleistocene glaciers 

 exceeding a mile in length were determined. Traces of several 

 smaller glaciers and of more than a dozen neve fields were also 

 found and mapped. Of the fifty larger glaciers, seven reached 

 the shore line of Lake Bonneville, and the moraines of at least 

 three of them are clearly seen to be partially buried by the 

 fluviatile deposits near the shore, or possibly by the shore 

 deposits of the lake itself. 



The elevation of a catchment basin necessary to give rise to 

 a glacier in this region, was between 8000 and 9000 feet, and, 

 except where the basins were very favorably situated, the latter 

 figure is more nearly correct. 



The crest line of the Wasatch Mountains is near the eastern 

 border of the range. The valleys of the west slope are there- 

 fore much longer than those of the east, and the glaciers of the 

 two slopes were, in a general way, of corresponding lengths. The 

 number of ice tongues on the west was also much greater than on 

 the east. Of the fifty glaciers over one mile in length, forty-six 

 were west of the crest, and but four east of it. Of the ten glaciers 

 which reach or exceeded five miles in length, nine moved west- 

 ward and but one eastward. The Little Cottonwood glacier on 

 the west slope was twelve miles long, while the greatest length 

 reached by any glacier on the east slope was five miles. East 

 of the crest, one glacier descended to an altitude as low as 6000 

 feet, and two others descended to 7000 feet. On the west slope 

 fourteen glaciers descended to an altitude of less than 6000 feet, 

 and seven to 5000 feet. 



The greater number and size of glaciers on the west side of 

 the range as compared with the east side, were determined by (i ) 

 the larger catchment basins, and (2) the heavier snowfall. A 



