(jflaciers both melt and flmv away. 35 



evidence to .show that the glacier is at present retreating, and 

 that its retreat is quite rapid, viz : The absence of forests in the 

 upper part of Glacier bay, the existence of fresh strife and of 

 glacial debris in situations where the material could not have 

 resisted erosive agencies for any great length of time, the small 

 amount of debris fallen from the mountains on the eastern side 

 of the inlet^ the small amount of vegetation on the shore near 

 the glacier, the transverse ridges on the shore, the mass of de- 

 tached melting ice in front of the glacier, and, finalW, the account 

 of Vancouver, which makes it probable that a large j^art of Glacier 

 bay was filled with solid ice a hundred years ago*. 



To these evidences I may add the following observations : On 

 the sides of the mountains bordering the glacier, and esijeciall}' 

 in the gullies on the northern slopes, there are masses of ice ex- 

 tending a hundred feet or more above the present level of the 

 glacier. This ice has been protected from very rapid melting bv 

 the delu'is which covers it. It must have been a connected jjart 

 of the glacier not many years ago. On the northeastern side of 

 Tree mountain there is a spur which projects into the ice of Main 

 valley. On its upper side and near its end the ice is only some 

 10 or 20 feet below its top ; on the lower side the ice is much 

 lower, ilcross this spur in a direction parallel to the valle}^ were 

 some small stream Ijecls, beginning abruptly at the upper side, 

 whose source must have been the melting ice when it was level 

 with the top of the spur. The whole spur was covered with 

 bowlders, sand, and some fine detritus. The stream JDcds were 

 marked only by the disposition of the sand. The fine detritus 

 must assuredly have been washed away by the rain and melting 

 snow if the spur had been uncovered many years. The ice 

 between G and the nunatak to the west is at a higher level than 

 the western or northwestern tributaries and slopes both toward 

 the north and the south. As this region has no independent 

 source of supply, it must have obtained its ice from the north- 

 western or western tributaries, which therefore must have been 

 at a higher level than they are now. If this subsidence had been 

 due entirely to melting, the surfaces of these two tributaries woiild 

 not have sunk more rapidly than that of the ice connecting them. 

 We are therefore forced to conclude not only that the ice is melt- 

 ing away, but also that it is flowing away. This process has 



*Ice Age in North America, 18S9, pp. 51-.17. 



n— Nat. ffF.oo. Mag., vor,. TV, isn2. 



