THE NEW ZEALAND SOUND BASINS 31 



from forms which we know to be developed by streams in non- 

 glaciated areas. ^ 



Here, then, is strongly suggested a glacial origin for these forms. 

 In the succeeding pages an explanation of these geographic features 

 is attempted. 



Fig. 6. — The northern wall of Milford Sound. Note the alignment (and double 

 slope) of walls at Stirling Falls; also the "hanging" valley to the, extreme left. 



THEORETIC CONSIDERATIONS 



It is here proposed to explain the peculiar topography of the 

 southwestern New Zealand sounds, lakes, and canyons as the result 

 of great ice-floods working along lines of preglacial drainage, devel- 

 oped to late youth or early maturity in lofty plateaus having rapid 

 fall to baselevel (generally sea-surface), and to show that the present 

 glaciers must necessarily, from analogy with ordinary stream-action, 

 be practically stagnant. . . 



The similarity between ice- and stream-action need not be at all 



I Similarly for the like features of the once strongly glaciated fiord regions of 

 Alaska, Norway, and Patagonia. 



