60 GLACIOLOGY 



The outline of Mount Crummer, and the outlook from the Backstairs Glacier, 

 in the direction of Mount Melbourne, are shown on the sketches on Plate XIII. 



The David Glacier. This glacier is another of the outlet or spillway type. 

 At Cape Philippi it is about 8 miles in width. It also appears to be about 

 25 miles in length. Heavy ice-falls could be seen far inland up this glacier as 

 viewed from the sea ice. Its surface is so rugged as to be almost impassable. 

 It is evidently an Important outlet for the snow-fields of the plateau. Its great 

 pressure ridges, shearing jjlanes, and numerous crevasses testify to its activity. 



Snotv-Jields and Ice-fields of the Magnetic Pole Plateau. Plate XIII. Fig. 3 

 shows the general appearance of the snow-fields at the back of Mounts Larsen and 

 Gerlache. 



A study of this photograph makes it clear that the summits of Larsen and 

 Nansen would be easily overridden by an ice sheet were the snow surface about 

 2000 feet higher than it is at present. 



The surface of the plateau was found to undulate in broad billows about 40 to 

 50 feet deep, and many hundreds of yards from crest to crest. A crevasse was 

 observed as far inland as 55 miles from the coast, and ice-falls, formed above of 

 hard marbled snow, were observed at a total distance of 70 miles inland. The 

 whole snow-field must, therefore, be in a state of slow movement, at least as far 

 inland as this. Strong undulations in the snow surface, still about 50 feet deep 

 from trough to crest, continued inland for fully 90 miles back from the shore, 

 and 70 miles back from the inner edge of the plateau horst. From this last 

 distance of 90 miles inland the undulations lessen, and could not be recognised near 

 the summit of the plateau. This attains an altitude of 7350 feet at a distance from 

 the coast at the Reeves Glacier of 180 miles. No trace of any material approaching 

 to ice could be seen on the inland side of the ice-falls, the latter being situated 70 

 miles inland. 



A sketch of the general outline of the ranges bounding the Reeves Glacier from 

 Mount Nansen north-westwards through Mount Baxter and Mount Mackintosh is 

 shown on Fig. 1 5 and on Fig. 4 of Plate XIII. 



The plateau character of the Inland ranges is very obvious in the sketches ; some 

 of the rocks — particularly those of Mount Mackintosh — appeared to be very black, 

 which suggests that they may be formed of basic material. They are lai'gely 

 formed of Beacon Sandstone. It will be noticed from the section on Plate XIV. that 

 the summit of the Magnetic Pole Plateau is very flat, not varying in height by more 

 than 50 feet over a distance of 30 to 40 miles. In a distance of 35 miles a fall of 

 about 90 feet was recorded by us in a general direction towards the north-west from 

 the summit of the plateau to the farthest point reached north-west. Our direction of 

 march at the time was about N. 30° W., and it was in this direction that the slight 

 fall was recorded. It does not, of course, follow that this was the direction of 

 greatest fall. That we actually passed over the summit of the plateau before reach- 



