STUDIES OF THE CYCLE OF GLACIATION 
WILLIAM HERBERT HOBBS! 
University of Michigan 
I. THE CYCLE OF MOUNTAIN GLACIATION WITHIN 
MODERATE LATITUDES 
In a general discussion of glacial sculpture in mountains,” the 
writer has made use of the terms grooved or channeled upland 
and fretted upland to describe respectively the early and the late 
effects of the erosional action of mountain glaciers. The Bighorn 
Mountains in Wyoming and the Swiss Alps were chosen as type 
examples of these contrasted erosion surfaces, the characteristics 
of which are, that in the former large areas of the preglacial upland 
still remain (Figs. 1, 2, and 3), while in the latter its complete 
dissection by cirque recession and enlargement has resulted in a 
system of main and secondary rock palisades described as comb 
ridges. Between these contrasted land surfaces many gradations 
exist, though examples of the former are relatively uncommon. 
Similar to the channeled upland of the Bighorn Mountains, though 
with less of the preglacial surface retained, are portions of the 
Uinta and Wasatch mountains, of which excellent illustrations 
have been supplied by Atwood. All the best examples are 
furnished by the Rocky Mountains in the interior of the American 
continent, where the moist westerly winds have been robbed of 
their moisture in crossing the high Sierra Nevada and Cascade 
ranges. 
In a visit to the Glacier National Park, the writer was impressed 
with the fact that a type of topography is there represented which 
indicates a still later stage of sculpture by mountain glaciers than 
t [llustrations from photographs by the author. 
2““The Cycle of Mountain Glaciation,” Geogr. Jour., Vol. XXXV (1010), pp. 
147-53, Figs. r-19. Also, “‘Characteristics of Existing Glaciers,” pp. 25-40, 
RISsie Sor 
3 “Glaciation of the Uinta and Wasatch Mountains,” U.S. Geol. Survey, Prof. 
Paper 61 (1909), maps of Pl. 8A. 
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