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PHYSICAL GEOLOGY 



them measures over 10 miles, but the great majority are less 

 than a mile in length. They vary in width from a few hundred 

 feet in the case of the great majority, to a mile or more. The 



FIG. 202. Glacier de la Brenva descending from Mont Blanc on the Italian 

 side. (R. T. Chamberlin.) 



largest ones are several hundred feet thick. Large valley gla- 

 ciers occur also in the Caucasus, Himalaya, and other mountains. 

 Feeding grounds. Deep snow fields occupy the heads of 

 mountain valleys containing glaciers. Fed by snowfall in the 

 valley, by avalanches from the inclosing slopes, and by wind- 



