VOLCANIC ACTIVITY 



down to the shore, where the ice either breaks off to 

 form a cliff or, as at Glacier Tongue, spreads out sea- 

 wards in the form of a narrow blue pier about five 

 miles in length. Near Cape Royds, however, there 

 are long smooth ridges of brown glacial gravels and 

 moraines, mostly bare of snow. These are inter- 

 spersed with masses of black volcanic rock, and extend 

 to an altitude of about 1000 ft. Above this and up 

 to about 5000 ft. above the sea, all is snow and ice, 

 except for an occasional outcrop of dark lava or a 

 black parasitic cone sharply silhouetted against the 

 light background of snow or sky. At a level of about 

 6000 ft. and just north of the second or main crater, 

 rises a huge black fang of rock, the relic of the oldest 

 and lowest crater. Immediately south of this the principal 

 cone sweeps upwards in that graceful double curve, con- 

 cave below, convex above, so characteristic of volcanoes. 

 Rugged buttresses of dark volcanic rock, with steep 

 snow slopes between, jut out at intervals and support 

 the rim of this second crater, which reaches an altitude 

 of fully 11,400 ft. From the north edge of this crater 

 the ground ascends, at first gradually, then somewhat 

 abruptly, to the third crater, further south. It is 

 above this last crater that there continually floats a 

 huge steam cloud. At the time of Ross' expedition 

 this cloud was reddened with the glow of molten lava, 

 and lava streams descending from the crater are also 

 described. On the Discovery expedition we saw a 

 glow once or twice during the winter months, but we 

 were then situated about twenty-eight miles from the 

 summit, so that possibly there were at times faint 

 glows which we did not see, and, besides, it was neces- 

 sary to go two or three hundred yards from the ship 

 before the mountain, which was hidden by the local 

 foot-hills, appeared in view. In our winter quarters 



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