A MONTH WITH THE MUIR GLACIER. 57 



parts, only on a diminished scale ; but in the upper half of 

 the bay all the shores and islands are perfectly bare of forests, 

 and the rocks retain in the most exposed situations fresh 

 grooves and stria? of glacial origin. It would be impossible 

 for rocks so exposed in such a climate to retain these for an 

 indefinite length of time. Far up on the mountains, also, 

 there are remnants of glacial debris in situations such that 

 the material could not have resisted erosive agencies for any 

 great length of time. The triangular-shaped terminal moraine 

 on the eastern side, just below the ice-front, presents some 

 interesting features bearing on the same point. This extends 

 three miles below the glacier, and in its lower portions is 

 thinly covered with vegetation. This covering becomes less 

 and less abundant as the glacier is approached, until, over the 

 last mile, scarcely any plants at all can be found. Apparently 

 this is because there has not been time for vegetation to 

 spread over the upper portion of the moraine since the ice 

 withdrew, for on the mountains close by, where the exposure 

 has been longer, there is a complete matting of grass, flower- 

 ing plants, and shrubs. Again, in this triangular moraine- 

 covered space there are live distinct transverse ridges, mark- 

 ing as many stages in the recession of the ice-front (see Fig. 

 24). These moraines of retrocession run parallel with the 

 ice-front on that side, and at about equal distances from each 

 other, each one rising from the water's edge to the foot of the 

 mountain, where they are 408 feet above tide. An inspec- 

 tion of the upper moraine-ridge shows the manner of its for- 

 mation. This transverse ridge is half a mile below the ice- 

 front, and is still underlaid in some portions with masses of 

 ice ninety feet or more in thickness, which are melting away 

 on their sides and allowing the debris covering them to slide 

 down about their bases. Kettle-holes are in all stages of for- 

 mation along this ridge. The snbglacial stream emerging 

 from the southeast corner of the glacier next the mountain 

 rushes along just in the rear of this moraine-ridge, and in 

 front of a similar deposit in process of formation on the very 

 edge of the ice where the medial moraines spoken of termi- 



