44 



outlines and lack of glacial rounding. The sand banks 

 off the coast indicate that the ice extended even on and 

 into the ocean for some distance from the coast. 



Rivers and streams are abundant in this region, and, 

 although in general short and draining relatively small 

 areas, they are of large volume during the summer months 

 because of the excessive precipitation and the melting of 

 the snow in the mountains. Several of the rivers, notably 

 the Stikine, Taku, Chilkat, and Alsek, rise in the interior 

 plateau country beyond the Coast range and are evidently 

 antecedent to it in character. The Stikine river is navig- 

 able up to Telegraph Creek, British Columbia, 170 miles 

 (273 km.) from the coast. Most of the rivers enter salt 

 water at the head of a fiord, but many streams from tribu- 

 tary 'hanging valleys terminate as waterfalls, plunging 

 1,000 feet, (300 m.) more or less, down the walls of the 

 master valley and adding greatly to the charm of the 

 landscape. Many of these waterfalls are the outlets of 

 lakes hidden behind the bed-rock lip of the hanging valley, 

 and such streams may well serve later on for the commercial 

 development of power for different purposes. 



Southeastern Alaska is essentially an upland area of 

 high relief, deeply dissected by valleys and canyons. The 

 uplands slope in general toward the Pacific, and exhibit in 

 places a tendency toward uniformity of their summit 

 levels, which there have the appearance of an uplifted, 

 warped, and much incised base level of erosion. They 

 have been so interpreted, but there are certain objections 

 to this simple hypothesis of an elevated peneplain which 

 have not been entirely removed and will have to be met 

 before it can be finally accepted. It is possible that both 

 the observed tendency toward planation in the uplands 

 and also in the forelands noted above, owe their present 

 character to ice action. It is significant in this connection 

 that the upper limit of ice action coincides with the upland 

 base level. If the ice sheet remained long enough at 

 approximately the same level its surface might well have 

 functioned, like a large water surface, as a datum plane 

 toward which the exposed land masses tended to be 

 bevelled. Sufficient evidence has not yet been gathered 

 to determine definitely the role, which such ice-cap beveling 

 may have played in the formation of the observed upland 

 surface. 



The structure of Southeastern Alaska is exceedingly 

 complex, and has been studied at relatively few points. 



