126 Gregory — Progress in Interpretation of Land Forms. 



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; bnt 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 verticality of the ivalls haying 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 I 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, lie says : 



"Glacial erosion has cut almost vertically down through the 

 beds carving immense amphitheatres with basin bottoms con- 

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

 an absolutely trivial work. There is not a particle of direct 

 evidence, so far as I can see, to warrant the belief that these 

 U-shaped canons were given their peculiar form by other means 

 than the actual ploughing erosion of glaciers. ..." 



These contributions from the Cordilleras corroborat- 

 ing the conclusions of Ramsay (1862), Tyndall (1862), 

 Jukes (1862), Hector (1863), Logan (1863); Close (1870), 

 and James Geikie (1875), made little impression. The 

 views of Lyell (1833), Ball (1863), J. W. Dawson (1864), 

 Falconer (1864), Studer (1864), Murchison (1864, 1870), 

 Ruskin (1865), Rutimeyer (1869), Whymper (1871), 

 Bonney (1873), PfafT (1874), Gurlt (1874), Judd (1876), 

 prevailed, and the conclusions of Davis in 1882 72 fairly 

 expressed the prevailing belief in Europe and in 

 America : 



