456 ARTHUR BEVAN 



are commonly present, with the uppermost one several hundred feet 

 above the present streams (Fig. 8) . 



Glacial drifts — Glacial drift in the form of typical moraines and 

 outwash gravels is present in most of the valleys on the east and 

 northeast slopes of the range. This drift was deposited by fifteen 

 systems of alpine glaciers, many of which contained numerous large 

 tributaries. The outermost moraines commonly exist from 2 to 

 6 miles beyond the mountain front, but in a few valleys they are a 



fe«S<MN~«(S « i,' «^>. 



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Fig. 8. — Terraces along West Fork of Rock Creek, southwest of Red Lodge 



short distance within it. A few of the lateral moraines below the 

 canyon mouths are huge ridges that attain heights of 500 to i ,000 

 feet above the valley floors (Fig. 9). Drift of two distinct epochs, 

 probably corresponding to early and late Wisconsin, is clearly 

 recognized in several valleys. An impressive characteristic of the 

 recent drift is the abundance of large bowlders strewn over its 

 surface. In some valleys the later glaciers advanced beyond the 

 earlier ones, whereas in others the older lateral moraines extend a 

 mile or two beyond the younger terminal moraines, 



A considerable portion of the southwest slope was occupied by a 

 large ice sheet which left an abundance of striated and polished 



' A paper on the glaciation of the range is being prepared by the writer. 



