4i8 
SCOTT'S LAST EXPEDITION 
is an example of a peneflain. It was formed in middle 
Tertiary times, and bears all the evidence of ' old age ' 
in a land surface. As we have seen, it has been elevated 
and now the rivers are cutting it down again, forming 
canyons all round its coastal edges, and the ' cycle of 
erosion ' has commenced anew. In Antarctica the land 
below the central ice plateau would appear to be a similar 
peneplain. The comparatively slight depth of the outlet 
glaciers seems to indicate that the ice cap is not very thick, 
probably one or two thousand feet only. The peneplain 
is, however, elevated to eight thousand feet instead of 
one to three thousand as in Australia. 
It is, however, with the margin of the ice cap that 
these few pages are concerned. Just as in Australia 
beautiful canyons and falls have resulted from the attack 
of the weather on the margins of the plateau, so in 
Antarctica the ice rivers and agents of frost erosion have 
carved out their own characteristic topography. 
We know from the fossils that warmer conditions 
existed in Mesozoic times in Antarctica, probably in early 
Tertiary times. Moreover, the elevation of the land so 
many thousand feet has undoubtedly given rise to a per- 
manent 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 f re-glacial topography 
such as might be shown by a moulding of the inland ice 
cap. We may picture the rock surface like that of up- 
land Norway, as a gently rolling plateau. As the ice 
mantle covered Antarctica, occupying the more pro- 
