INTERPRETATION OF LAND FORMS 145 



the ice was unusually powerful, especially where, as in the low- 

 lands of Switzerland, the Miocene strata are comparatively soft.' 1 



Whittlesey (1864) 69 considered that the rock-bound 

 lakes and narrow bays near Lake Superior were partly 

 excavated by ice. LeConte (1875) 70 records some sig- 

 nificant observations in a pioneer paper on glacier 

 erosion which has not received adequate recognition. 

 He says: 



". . . I am convinced that a glacier, by its enormous pressure 

 and resistless onward movement, is constantly breaking off large 

 blocks from its bed and bounding walls. Its erosion is not only a 

 grinding and scoring, but also a crushing and breaking. It 

 makes by its erosion not only rock-meal, but also large rock- 

 chips. ... Its erosion is a constant process of alternate rough 

 hewing and planing. 



If Yosemite were unique, we might suppose that it was 

 formed by violent cataclysms; but Yosemite is not unique in 

 form and therefore probably not in origin. There are many 

 Yosemites. It is more philosophical to account for them by the 

 regular operation of known causes. I must believe that all these 

 deep perpendicular slots have been sawn out by the action of gla- 

 ciers ; the peculiar verticahty of the walls having been determined 

 by the perpendicular cleavage structure." ... A lake in Bloody 

 Canyon "is a pure rock basin scooped out by the glacier at this 

 place. . . . These ridges [separating Hope, Faith, and Charity 

 valleys] are in fact the lips of consecutive lake basins scooped 

 out by ice. 



. . . Water tends to form deep V-shaped canons, while ice pro- 

 duces broad valleys with lakes and meadows. ... I know not 

 how general these distinctions may be, but certainly the Coast 

 range of this State is characterized by rounded summits and 

 ridges, and deep V-shaped canons, while the high Sierras are 

 characterized on the contrary by sharp, spire-like, comb-like 

 summits, and broad valleys ; and this difference 1 am convinced 

 is due in part at least to the action of water on the one hand, 

 and of ice on the other." 



King (1878) 71 assigned to glacial erosion a command- 

 ing position in mountain sculpture. In regard to the 

 Uintas, he says : 



"Glacial erosion has cut almost vertically down through tho 

 beds carving immense amphitheatres with basin bottoms con- 

 taining numerous Alpine lakes. . . . Post-glacial erosion has done 



