A single Glacier now advancing. 153 



smooth convex surface and feather edge characteristics of stag- 

 nant ice at the front of a retreating glacier. 



Taken altogether, the ice floMdng northward from the St Elias 

 mountains is insignificant in amount when compared with that 

 flowing southward. The Seward glacier alone probably contains 

 a greater volume than all of those flowing into the White river 

 basin combined. The great difference in climatic conditions, on 

 which the formation of glaciers depend, is indicated by the 

 difference in altitude of the lower limit of the neve snow on the 

 north and south. According to Russell's observations about 

 Yakutat bay and my own on Prince William sound, that limit 

 on the seaward side of the mountains is at an altitude of about 

 2,000 feet, while on the north the altitude of the lowest neve 

 observed was 6,300 feet. This rise in the snow line toward the 

 north, over 4,000 feet in a distance of about eighty miles, is an 

 important fact in the consideration of the causes of giaciation, 

 either local or general. 



The Nizzenah river rises from one lobe of Russell glacier and 

 in the upper part of its course is fed by a number of glaciers 

 coming in from the high mountains on either side of Scolai pass. 

 One of these, the Frederika, possesses a peculiar interest in that 

 it appears to be the only well marked case among Alaskan 

 glaciers of active advance at the present time. Flowing south- 

 ward in a lateral valley which joins that of the Nizzenah at right 

 angles, its front is parallel with the river and about three-quar- 

 ters of a mile distant, the intervening space being a smooth 

 gravel plain. The glacier terminates in a nearly vertical ice cliff 

 stretching across the lateral- valley a mile in length and about 

 250 feet high. Its surface is free from moraine, but is extremely 

 rough and broken, wholly unlike the surface of stagnant ice at 

 the end of a retreating glacier. At the foot of the cliff there is 

 a small accumulation of gravel and ice fragments, apparently 

 being j^ushed along by the advancing mass. 



Since the same climatic changes must affect all the glaciers of 

 the region alike, the cause of this anomalous advance must be 

 sought in some peculiar local condition affecting this glacier 

 alone. A simple explanation is suggested, though it must be 

 regarded merely as a suggestion since no means of verification 

 are at hand. Ten miles to the westward of the Frederika another 

 and much larger glacier flows into the valley of the Nizzenah. 

 This is formed by the union of three separate streams, and of 



