BY K. C. ANDREWS. 815 



selves. In youthful dissection one finds the greatest discordances 

 in these channel rock-slopes; while in extreme old age the grades 

 are almost perfectly harmonious : in other words, in areas of 

 little or no relief gravitative thrust is reduced to a minimum. 



Believing firmly in Gilbert's principle, the writer has ventured 

 to announce the existence of certain land-contours the world over 

 on the assumption of such principle. Contours in glaciated 

 regions have been specially selected for consideration because of 

 the various conflicting views entertained as to their origin. 



A. Glacial pheiiomena. 



(a) Fiord regions. — Alaska, New Zealand, Norway, 

 Patagonia. 



The following deductions are based partly on the belief that in 

 these regions fierce but short-lived glacial floods acted along pro- 

 found stream-formed canons, and, in part, also, on the belief that 

 glacial action is analogous to that of water streams. This con- 

 clusion is based on a comparison of glaciated and non-glaciated 

 western New Zealand. The contours expected in glaciated areas 

 on such analogy would be much as follows : — 



i. Canons of profound depth with comparatively wide and flat 

 floors. 



ii. Rectilinear walls in part. Compare Fig. 3 illustrating 

 roadside gutter-development during floods whereby deep straight 

 trenches are excavated. 



iii. Floors of canons interrupted frequently by terraces possess- 

 ing, approximately, amphitheatrically shaped heads. Compare 

 Figs. 4 and 7. 



iv. Canons terminating frequently in magnificent cirques. See 

 Figs. 2 and 3. 



V. Cirques or, at times, precipices under smoothed cols. 



vi. Basins at feet of cirques with reversed grades lower down- 

 stream. Compare with Fig. 2. 



vii. Canon floor-grades interrupted bj' basins at various points: 



(a) At marked canon-convergences, especially where the main 

 valley is but slightly larger in cross-sectional area than either of 

 ts feeders. ^f ; '■ (j. ^ / 



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