THE NEW ZEALAND SOUND BASINS 47 



Of course, in an area of preglacial drainage carried to late maturity 

 or early old age, especially in areas of gentle or moderate relief only, 

 we would expect comparatively little action to be manifest even during 

 the height of the ice-flood. This point should always be kept in 

 mind by anyone comparing such widely varying regions as England, 

 the Canadian plains, or Norway. 



Where the stream-flood dashes its load angrily along the torrent 

 tracks of a youthfully dissected plateau, there should we expect to 

 see the vigorous thrusts of converging canyon glaciers. Now, Alaska, 

 Norway, New Zealand, and Patagonia ( ?) are countries having 

 young profound canyons intrenched in high plateaus. New England 

 and many other places appear to have had their preglacial drainage 

 well advanced. Apart, then, from certain minor features in their 

 canyoned plateaus, we should expect to see evidence only of com- 

 paratively sluggish glaciers. This also applies to Fairchild's criti- 

 cism on p. ^T,. 



(Pp. 34, 35) Greenland has passed through its ice-flood phase 

 as well as other regions, and therefore its glaciers should now be 

 stagnant as compared with their ice-flood representatives. The main 

 work was accomplished along the centers of the preglacial drainage 

 lines, and the swarming of the ice- cap over areas of irregular hills 

 and hollows is analogous to the "backing-up" action of ordinary 

 flood waters against obstacles. During the height of the flood the 

 grades of the old drainage were altered to meet the requirements of 

 the heavy ice-cap. Now, of course, heavy as the ice-masses are, 

 they are hopelessly incompetent to the task of corrading these old 

 channels. 



Even during the maximum ice onslaughts the ice in inter-stream 

 areas could only corrade strongly if it discovered (or formed) a 

 drainage line. Otherwise it would simply override hills and aggrade 

 here and there.' 



(Pp. 37, T,S) Referring to Professor A. C. Lawson's description 

 of the Kern Valley, we venture to suggest that the previous notes 

 explain these features. 



(Pp. 39, 40) Without having seen Lake Chelan, we venture to 

 suggest that it may be analogous to certain apparently non-strongly 

 glaciated valley portions in New Zealand. Yet this is to be expected, 



