PLATEAU AND MOUNTAINS 287 
undoubtedly given rise to a permanent refrigerating system of 
winds which has made Antarctic coasts much more inclement than 
they would have been with a less elevated interior. 
There is practically no trace of pre-glacial topography such 
as might be shown by a moulding of the inland ice cap. We may 
picture the rock surface like that of upland Norway, as a gently 
rolling plateau. As the ice mantle covered Antarctica, occupying 
the more pronounced swellings first, and then spreading in lobes 
of ice down the broad depressions, we may imagine that a very 
little difference in the contour might determine the position of 
the great outlet glaciers where the ice cap drained away to the 
sea. In other words, the glacier valleys do not appear to owe 
much to pre-glacial topography. 
Let us now survey the marginal mountain range and the ice 
plateau more closely. ‘The plateau seems to rise to 11,000 feet 
near the South geographic Pole, and decreases gradually to the 
north, being about 7000 feet at the South magnetic Pole. The 
mountain ranges have peaks, such as Markham and Lister, rising 
to 15,000 and 13,000 feet respectively, but the average height 
is perhaps about 9000 or 10,000 feet, while for considerable 
stretches near Granite Harbour they are only 6000 or 8000 feet 
high. Every 20 or 30 miles this fairly continuous range is broken 
by a huge ‘ outlet’ glacier. Many of these are now well known, . 
such as the Beardmore, which is over 100 miles long and 30 
miles wide, the Ferrar, Mackay, David, &c. They form the 
only routes from the coast to the interior, and were it not for 
the ice falls where the glacier covers some irregularity in its rock 
floor, or the more dangerous crevassed areas, where it sweeps 
round a corner, or receives the thrust of a large tributary, they 
would not be difficult to traverse with sledges. The grade is not 
very steep, and they are to some extent sheltered from the bliz- 
zard drift which is the great obstacle to Barrier and plateau 
journeys. Their detailed topography is however very different 
from that of an area subjected to ‘normal’ erosion. 
The regions more especially investigated in the two sledge 
journeys of the Western Geological Parties in 1911 and 1912 
were the following: 
(a) The Ferrar and Taylor outlet glaciers (77° 40’). 
(b) The Koettlitz ice delta and its hinterland (78° 20’). 
(c) Granite Harbour and the Mackay outlet glacier (77°). 
