48 E. C. ANDREWS 



since some portions of a stream bed are preserved, while others are 

 deeply corraded during flood stages. But in every instance in the 

 New Zealand fiord region where lake basins, etc., occur, we could have 

 predicted the same from the peculiar conformation of the associated 

 canyon structures. Lake Chelan should be studied with this in view. 



(P. 41) To the objections raised on this page it can only be again 

 said that ice-action in infantile, youthful, mature, and other phases 

 of plateau-dissection must not be confounded. 



(P. 42) This present condition of the Muir and other glaciers is 

 what must result on the assumption of a former eflicient ice-flood. 

 The glaciers are now in their drought stages, and lack all capacity 

 for corrasion along their old hasined channels. 



(Pp. 42-46) Fairchild, in criticising Dr. Gilbert's report, appar- 

 ently considers that physiographers claim the general deepening 

 of fiords, etc., to the extent of thousands of feet. Now, in New 

 Zealand, these rock basins, although immense, are yet only a portion 

 of the canyon lengths, and mark the points of convergence of deep 

 canyons. Along the upper canyons for many miles the floor may 

 be flat or exist as a series of terraces.^ 



Thus Wakatipu arises from convergence of the Dart and Rees 

 canyons; Milford Sound arises from convergence of the Arthur and 

 Cleddau valleys; while these valleys themselves are fairly flat, and 

 their bases are probably nearly '2,000 feet above the lake and sound 

 floors. 



With respect to the differential erosion along the fiords (i. e., pre- 

 glacial drainage channels), and on Annette Island, it must always 

 be remembered that, as a rule, in the converging narrows the streams 

 scour, while on the associated broads they aggrade. 



As for the view, held possibly by some, that the fiords are wholly 

 the product of ice-scour, all the physiographic evidence in New 

 Zenland points to the fact that the ice-action was confined to working 

 fiercely along the central drainage lines, with production of local 

 spurless chasms, rock basins (sounds and lakes), and double wall 

 slopes, alternating with comparative stagnation of glaciers at points 

 where one would expect stream-action to be expended in aggrading. 



I See also Willard D. Johnson, " The Profile of Maturity in Alpine Glacial Erosion," 

 Journal of Geology, Vol. XII, No. 7 (1904). 



