THE ICE AGE 



period which preceded it animals which now live in the 

 tropics roamed in the Arctic circle, and figs and magnolias 

 grew in Greenland. 



The last word we shall have to say on the climatic 

 conditions of this period is that the Ice Age had its 

 sub-periods and divisions like all other epochs and in 

 them the ice sometimes retreated, and consequently in 

 parts of the earth where there had been snow and ice, 

 and where there were to be ice and snow again, the 

 wintry conditions retreated (for centuries, perhaps, at a 

 time), and the valleys and plains basked during these 

 intervals in sun and rain and warmth. These epochs are 

 called " inter-glacial epochs." 



The life of the regions not much affected by the 

 rigours of snow and ice is gradually being ascertained 

 by geologists now. One of its most marked features 

 was the retreat of the northern and Asiatic animals 

 before the advancing ice towards the warmer tropics and 

 Equator ; these animals journeyed back northward again 

 whenever the retreating ice would let them. The great 

 Proboscideans, the Mastodon and the Mammoth were 

 members of this group, and so were the bear, the bison, 

 the musk ox. With these mingled towards the south 

 several types (which were gradually becoming extinct in 

 North America) such as the horse, tapir, llama, and the 

 sabre-tooth cat. A second prominent feature was a 

 southern group in the western hemisphere, consisting of 

 gigantic sloths, armadillos, and water-hogs ; and now for 

 the first time the interest of animal life shifts to South 

 America. 



s 273 



