TJie Dyiny Glacier. 37 



lower than the surface of the ice when at its greatest flood. It 

 is now without supply, and is rapidly melting awa5^ 



Another element of the diminution of the glacier, and one 

 which would appeal much to most persons, is the retreat of the 

 ice-front. In the four years between Professor Wright's visit, in 

 1886, and my own, in 1890, the ice-front receded more than 1,000 

 yards (see further, page 41). 



Extent and Date of the last great Advance. 



On the northeastern side of Tree mountain the lower slopes 

 are covered with moraine debris and with very slight vegetation. 

 At a height of about 2,000 feet above tide large trees (spruce) are 

 found growing, some of which are quite a foot in diameter and 

 must be over a hundred years old. Above this limit the moun- 

 tain is free of erratics. On the opposite side of INIain valley 

 there is a very noticeable line about the same height, marked by 

 a variation in the shrubbery, although there are no trees on these 

 mountains. This, then, is the highest point reached by the glacier 

 in this part. The rounding and scratches show that nunatak G, 

 1,855 feet above tide, was covered, as were also the islands in 

 Glacier bay, one of which (Willoughby) is 1,000 or 1,500 feet 

 high. The height of scratches and erratics in the neighborhood 

 of the glacier's mouth we did not determine, but the height given 

 by Professor Wright (2,500 feet) seems to me a little too high. 

 At F (3,000 feet) no erratics were found, and as the ground 

 here is well adapted to retain them we must conclude that the 

 glacier did not rise to this height. I am inclined to think the 

 scratches observed by Professor AVright at a height of 3,700 feet * 

 are due to local causes. 



The advance of the ice from Muir and other glaciers of Glacier 

 bay must have been near its maximum at the time of Vancouver's 

 visit, 100 5^ears ago, for it seems probable from his narrative that 

 the ice extended below Willoughby island, and the large trees 

 on the islands in the lower part of Glacier bay show that it did 

 not extend that far. That the height given, 2,000 or 2,500 feet 

 was that of the last great advance seems pretty certain from the 

 freshness of the scratches up to that limit. Moreover, if at the 



* This would make the ice at this point several hundred feet higher 

 than at Tree mountain, which is extremely improbable. Probably only 

 a small error would be made if we take 2,000 feet as the maximum height 

 of the ice near its present ending. 



