130 ALASKA GLACIERS 



water do not in general rise very nearly to the plateau 

 plane, and we were frequently able to see that those 

 farther back are higher. Even where the channels 

 between islands are most sharply incised it is probable 

 that they are excavated in the bottoms of broader hollows. 



My general conception of the configuration at the date 

 of the lower peneplain a conception necessarily vague, 

 as well as provisional is that it included all phases of 

 the topographic cycle, being infantile to adolescent where 

 the rocks are most resistant, adolescent to mature in the 

 greater part of the Alexander Archipelago, and senile 

 where the rocks are weakest. In the granites were nar- 

 row gorges, set far apart, and reduced to low grade only 

 where draining large tracts. Between them were tabular 

 uplands with mild relief, except for occasional unreduced 

 peaks, or monadnocks. In the stronger metamorphics a 

 system of graded waterways divided the upland into 

 mountain ridges, with scattered remnants of the summit 

 plain. The master streams were largely consequent to 

 the seaward slope of the old plain, but were in part 

 diverted to lines of strike; and minor streams were ad- 

 justed to rock structure. 



LOIV Peneplains. Along the passages and channels 

 we traversed, bold coasts are the rule and forelands of 

 any character the rare exception, but at two localities we 

 saw unmistakable traces of a peneplain between mountain 

 base and the descent to deep water, and in the light of 

 their evidence it seemed proper to give a similar interpre- 

 tation to various features of obscurer character. 



Annette and Gravina islands lie next to the mainland 

 in the southern part of the Alexander Archipelago. Out- 

 side them on the west is the great Prince of Wales Island, 

 from which they are separated by a broad channel, 1,500 

 to 1,700 feet deep. Each island contains a mountain mass 

 bordered on the west by a low foreland, the foreland being 



