THE VARIATIONS OF GLACIERS 259 



and showed by a map the changes which have taken place there. 

 They found that the ice-front had retreated to a distance of from 

 3 to 3I miles from its former position, and almost the whole inlet 

 was covered with floating ice very closely packed together. The 

 ice-front now passes from the base of Mount Case northwesterly 

 to the two small nunataks opposite, which have become united 

 into one by the lowering of the ice. It then passes southwesterly 

 to the corner of the large nunatak which separates Morse Glacier 

 from the Muir. An area of 4I square miles has thus been taken 

 from the glacier and added to the inlet. An area of 9 square miles 

 of the inlet is closely covered with floating ice. The amount of ice 

 which has been broken off from the glacier — if we assume an average 

 thickness of 700 feet, which is probably not far wrong — amounts to 

 about 91,000 million cubic feet. This is about fourteen times the 

 amount formerly discharged annually into the inlet.' 



The ice forms a terrace along the eastern side of the mountains, 

 and Dirt Glacier ends as an independent tide-water glacier. Morse 

 Glacier, which had already become an alpine glacier, separated from 

 the Muir, no longer has its valley closed up by the latter's ice.^ 



The new ice-front is composed of two parts. The eastern part 

 from Mount Case to the nunatak consists of ice which is practically 

 stationary, whereas the western part receives all the active flow of 

 the glacier. This portion does not differ materially in breadth from 

 the old ice-front, and receives practically all the ice which was for- 

 merly discharged into the inlet. It stands up as a vertical wall prob- 

 ably about 200 feet above the water. In 1890 the surface of the ice 

 where the glacier now ends was 500-600 feet above sea-level, so 

 that this surface has been lowered 300-400 feet. The fact that the 

 ice stands up as a vertical wall makes it probable that the water is 

 fairly deep at this point, though probably not as deep as at the old 

 ice-front. If this is so, the velocity of the ice near the present end is 

 probably a little greater than near the old end, as the section is some- 

 what less. This causes a tendency to advance, but the position of 

 the end will probably remain almost stationary for some time; for 

 if it advances materially beyond its present position, it will find no 



' "Studies of Muir Glacier," National Geographic Magazine, Vol. IV (1892), p. 51. 

 * C. L. Andrews, "Muir Glacier," ibid.. Vol. XIV (1893), pp. 441-45. 



