Mmr (ihlct(-i' JRr</l()ii. Ahls],ii. ('iislitiK/. 225 
hihiis nil i//iiru'r-swfij)t iuoHiit(iiii.s.-— In general the inouiitain 
slopes ovei- which the ice has moved are swept pretty bare of loose, 
material. On the other hand such material is always present to a 
certain extent. It is largely transported material, left there by 
the melting ice. Sometimes, as on II, where there is much loose 
material, it is clearly native and has not been removed. The 
mountain slopes all around the eastern portion of the amphitheatre 
are covered with a great amount of such material, extending for a 
considerable distance below the surface of the ice. Some of this 
is foreign material left on the slopes of the mountains 
as the ice decreased in hight. l)ut a considerable propor- 
tion has disintegrated since tlie ice covering has Ijeen re- 
moved, and is yearly moving down the mountain sides 
aided by avalanches and spring floods, comi)letely filling 
the gap slowly forming between the mountains and the ice. This 
also indicates the inertness of the ice of that portion of the glacier, 
the melting lieing in(n'e rapid than its slow flow away from its 
highest point. Kven in more rapidly moving portions of the 
glacier this same phenomenon is manifested, as along the sides of 
nunatak II, and in the upper portion of the Dirt glacier valley. 
Sizr of moniiiicH on Mair yhicu r. — This great rapidity of dis- 
integration, and its excessive rapidity in the case of the slates is 
further indicated by the great size of the moraines on Muir 
glacier, especially those on the eastern portion. These lie like 
great embankments on the surface of the ice, are often of very 
considerable width, and contain an enormous amount of material 
most oi which was supplied by the disintegrating mountain peaks 
along tlie sides of the old valley glaciers which supplied the ice 
now lying here. The whole surface of this portion of the glacier 
is thinly covered with fine dirt and sand, partially supplied by 
winds V)ut large]}' embedded in the ice. The large amount of dis- 
integrated material that must have existed in this basin and which 
the glacier has removed, together with that constantly supplied 
during its existence would seem ample to account for the material 
that the glacier has brought, and is now bringing, down to Glacier 
bay, judging b}' the present rate of disintegration. The smaller 
size of the moraines on the central and Avestern portions of the 
glacier is readily accounted foi-. The branches from the wt'stand 
northwest are adjoined Ity quartz-diorite mountains which dis- 
integrate much less rapidly than the slates, being fissured less 
