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POPULAR SCIENCE REVIEW. 
The ocean is the great evaporating dish, the continent the 
condenser ; hence the larger glaciers of the southern pole, where 
the ice-wall of the land ice, which in Greenland stops some 
miles inland, here comes down into the sea itself (PL III.), 
ploughing up the sea bed, and spreading out its terminal moraine 
in the ocean. 
What length of time has elapsed since the Glacial epoch 
occurred we cannot pretend to say ; Mr. Belt estimates the date 
to have been 20,000 years since, Mr. Croll 200,000 years ago. 
We may therefore, I think, rest content -with the geological 
evidences of a modification of the climate afforded by the re- 
Fig. 3. 
A marine area almost surrounded by land. To contrast with Fig. 4, the South 
Pole having a land surface entirely surrounded by ocean. 
mains of glaciers and icebergs and the zoological evidence of a 
former change in the distribution of the mammalia telling the 
same story. 
I believe the musk-sheep and the mammoth were both prse- 
and post-glacial animals, and that the mammoth survived till 
after the climate became milder, but that he was a scarce animal 
from that time. The musk-sheep lives on still in Arctic North 
America.* The sabre-toothed lion ( Machairoclus ) is so rare 
* See the beautiful!' specimen lately presented to the British Museum by 
Capt. Feilden, the naturalist on board H.M.S. Discovery , and now on exhi- 
bition in the Zoological Gallery. 
