286 SCOTT'S LAST EXPEDITION 



of Eastern Australia now rise on the present coast (the old 

 divide) and flow inland to the central lowlands. The features 

 characteristic of this portion of the crust are therefore: an ele- 

 vated coastal region sloping gradually to the west and sharply 

 truncated by ' faults ' on the east. 



Let us now journey southward to Antarctica and take a 

 bird's-eye view of the coast of the Ross Sea and of the great 

 mountain range which leads from the Ross Sea and McMurdo 

 Sound almost to the Pole. We notice at once that this range 

 extends almost due north and south, as was the case in Australia, 

 that it practically constitutes the shore line, that it has a steep 

 eastern slope often dropping ten thousand feet in a few miles 

 and that it descends gradually on the west to a uniform land 

 mass of a plateau type. 



It seems evident that these points of resemblance are not 

 accidental. The great earth movements which affected Australia 

 in middle and late Tertiary times also affected Antarctica. A re- 

 adjustment of equilibrium raised the west and depressed the east 

 in both continents. The central portion of Australia, consisting 

 of ancient rocks which have been planed down to a uniform level 

 by the normal agents of erosion by rivers, wind, &c. is an 

 example of a peneplain. 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 gla- 

 ciers seems to indicate that the ice cap is not very thick, probably 

 one or two thousand feet only. The peneplain is however ele- 

 vated 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 



