8 
Chapter II. 
THE ROSS ARCHIPELAGO. 
This group of islands includes practically all the land within 50 miles of the 
‘Discovery’s’ winter quarters, and is the most extensive area not directly joined to 
the mainland. The group is important because it has long been a centre of volcanic 
activity, which continues even to the present day. 
Ross Island. 
Ross Island is practically made up of the volcanic cones, Mounts Erebus and 
Terror, Cape Bird (Mount Bird, as it may be called), and another convex dome, Mount 
Terra Nova, lying between Mount Erebus and Mount Terror. This island therefore 
consists of four distinct volcanoes, and of these the greatest, Mount Erebus, is still 
active. This mass of ejected material lies between latitudes 77° 9' and 77° 49' 8., and 
longitudes 1G6° 8' and 1G9° 10' E. It forms an island having roughly the shape of 
an equilateral triangle with a side of 50 miles. 
Soundings in the waters around this island are unfortunately incomplete, but the 
few that we have would seem to show that the depth is greatest close to the shore and 
decreases gradually outwards. Whether or not this anomalous deepening is due to 
overweighting of the crust by so many huge volcanic piles close together is not clear, 
but the occurrence is suggestive. 
Mount Erebus (Fig. 4) is 12,922 feet high, and was active when seen by Sir James 
C. Ross in 1841, “ emitting flame and smoke in great profusion.” * During our two 
years’ stay in Winter Quarters at its base the snow was always white and continuous to 
the summit, and only steam was ever seen to be erupted. On three sides the mountain 
rises directly from sea -level, and has flowing convex curves, which give it a very 
massive and undenuded aspect. Three stages in its history appear to be recorded in 
its contours. Of these the first was by far the most violent, and produced a cone with 
crater about 8 miles in diameter. The walls of this still stand, and encircle it as a 
girdle about G000 feet above sea-level. In profile, on the north side this ring appears 
as a strong outstanding crag, and is separated from the mountain-side by a deep notch, 
while on the south side there is only a mere shoulder to interrupt the regular convex 
curve. The second stage is rendered evident by the existence of the lip of a later 
crater at a height of nearly 11,000 feet. Old lava-streams from it, swept bare of snow, 
can now be seen. The latest stage is recorded by the present small cone, which has 
been built up asymetrically within the second, and from this steam now issues. Dr. 
Ross, 1 Voyage in the Southern and Antarctic Regions, 1839-43,’ 1847, vol. i, p. 216. 
