THE ARAPAHOE GLACIER IN 1902. < 



In the front range of the Rocky Mountains of Colorado are 

 several remnants of glaciers. One of these, the Arapahoe gla- 

 cier, 2 has an area at present of about one-half square mile. It 

 lies on the eastern slope of the continental divide, twenty-one 

 miles due west from the city of Boulder. It is inclosed by 

 nearly vertical walls five to seven hundred feet in height, form- 

 ing a deep cirque opening to the east. The valley leading east- 

 ward is that of a branch of North Boulder Creek. This valley 

 has been occupied by a glacier to a distance of at least eight 

 miles to the east. The bottom of the valley for four miles east- 

 ward from the present glacier is occupied by a series of lakes 

 resulting from the glacial action and the intervening topography 

 is marked by roche moutonees (Fig. 1). The front of the 

 glacier has retreated up this valley to its present position, and 

 its length has been thereby reduced from nine miles to one mile. 



The features of this glacier at the close of the summer of 

 1902 have a peculiar interest. The snowfall for the past three 

 winters has been deficient, and the melting in the ensuing sum- 

 mers has been excessive. The results of these climatic circum- 

 stances appear in a great contraction of the ice-covered area, 

 an unusual exposure of fresh moraines and, what is still more 

 important, an almost complete absence of snow below the neve. 

 This last condition is responsible for many fine exposures reveal- 

 ing the stratification of the ice, and for the complete uncovering 

 of crevasses, some of which stand open as much as ten feet. 



Moraines. — The bottom of the valley is far from being a 

 single trough, and the glacier is therefore by no means a single 



1 The observations on which this account is based were made in the last week of 

 August. The photographs were taken by Judge Junius Henderson, of Boulder, Colo. 

 The map is constructed from a survey made by Hugh F. Watts, of Boulder, Colo. 



2 For a general description of this glacier, its position, dimensions, shape, and 

 evidences of its true glacial character, see paper by Willis T. Lee, this Journal, 

 Vol. VIII, p. 647. 



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