THE GLACIAL PERIOD. 71 



During what is known as the Glacial Period, a time when 

 the climate of the Arctic regions seems to have prevailed over 

 the greater part of the earth, enormous glaciers, whose mo- 

 raines still exist, stretched from Patagonia across Brazil to 

 Pernambuco, and as far as the equator. Traces of large 



Fig. 16. SHEEP ROCKS. 



glaciers have been found also in Nicaragua, and, indeed, 

 great part of both hemispheres was covered not merely with 

 glaciers, but with an ice-cap, such as is now confined to Polar 

 latitudes. During that wintry time England, too, had her 

 snow mountains, and was for the most part covered with 

 ice. Certainly her valleys were occupied by glaciers, one 

 of which extended from Lincolnshire to within a few miles 

 of London, and, gathering up specimens of the various 



