Davis.] 46 [May 3, 



In his remarkable essay "On the Conformation of the Alps" (Phil. 

 Mag,, xxiv, 1862, 169-173), Tyndall certainly makes " use of the imagina- 

 tion," but hardly a "scientific use." The groundless assumptions that char- 

 acterize this paper stand in striking contrast with the care displayed in the 

 author's experiments on radiant heat and spontaneous generation. The 

 power of water to cut out valleys is denied because glacial scratches remain 

 in the Alps after a " million years " exposure to the weather, and the form 

 of the mountains is ascribed mainly to glacial action. Their known 

 geological structure is altogether disregarded. Indeed the paper is beyond 

 criticism. These extravagant views are somewhat reduced two years later. 

 (Phil. Mag., xxvir, 1864, 255-271, and thus appear in Hours of Exercise in 

 the Alps, 1871, 237-251). 



J. Leconte says the fact that the Yosemite and other similar canons in the 

 Sierra Nevada " have been occupied by glaciers, makes it almost certain 

 that they have all been formed by this agency." "I must believe that all 

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

 ciers." (Ancient Glaciers of the Sierras, Amer. Jo urn. Sci., v, 1873, 339. 

 See also his Elements of Geology, New York, 1878, 51, 534.) 



O. Fisher considers glacial action important in modelling the forms of 

 even Southern England. (On the probable Glacial Origin of Certain 

 Phenomena of Denudation, Geol. Mag., in, 1866, 483-487. For his views 

 on the glacial origin of lakes, see the Reader, Apr. 25, 1865.) 



A middle class take the very popular ground that although the 

 valley is not entirely due to ice-erosion, its cross-section profile 

 will show whether it has been occupied by a glacier or not. A 

 valley cut by water only is said to have a V-form ; a glaciated 

 valley is U-shaped. But the rule is not a safe one, for while it is 

 probable that glaciers have in some cases made changes of a con- 

 siderable and visible amount in the upper valleys, especially in 

 Norway and Sweden where their work was of great strength, 

 the conditions that control a valley's form are too complicated to 

 admit of so simple a division. 



This is after the manner of Campbell's alphabetical topography. 



Ramsay's views go far enough, without being unfairly exaggerated to in- 

 clude the making of all lakes or cutting of valleys by ice. In an article that 

 appeared two months after Tyndall's, above noted, he says " no true geolo- 

 gist is likely to assert that these valleys (in the Alps) have been mainly 

 scooped out from end to end by ice, for the reason that, since the disap- 

 pearance of the ice, running water in the formation of gorges, etc., has 

 comparatively effected so little." " The large valleys were in their main 

 features approximately as deep as now before they were filled with ice. 

 The belief is as old as Charpentier." (On the Excavation of the Valleys 

 of the Alps, Phil. Mag., xxiv, 1862, 377-380.) 



