THE CONTINENTAL GLACIERS OF THE "ICE AGE" 317 



The mutual relationships of nearly all the molded features 

 resulting from continental glaciation may be read from Fig. 344. 



The shelf ice of the ice age. Shelf ice, such as we have become 

 familiar with in Antarctica as a marginal snow-ice terrace floating 



FIG. 343. View of a drumlin, showing an opening in the till. Near Boston, Mas- 

 sachusetts (after Shaler and Davis). 



upon the sea, no doubt existed during the ice age above the Gulf 

 of Maine (see Fig. 324, p. 298), and perhaps also over the deep sea 

 to the westward of Scotland. Though the inland ice probably 

 covered the North Sea, and upon the American side of the Atlantic 



FIG. 344. Outline map of the front of the Green Bay lobe of the latest continental 

 glacier of the United States. Drumlins in solid black, moraines with diagonal 

 hachure, outwash plains and the till plain or ground moraine in white (after 

 Alden). 



the Long Island Sound, both these basins are so shallow that 

 the ice must have rested upon the bottom, for neither is of 

 sufficient depth to entirely submerge one of the higher European 

 cathedrals. 



