322 LECTURE XI. 



tte glaciers, that the old thin alluvium covered them, and that, 

 consequently, the beds in which occur the mammoth and the 

 rhinoceros with the bony septum, are of a somewhat later date 

 than the slate-coal beds. 



We now make a long stride to the north, where the glacial 

 formations attained the greatest extent. 



Kjeruh" very properly directs our attention to the observations 

 of Rink, who passed several years in Greenland, where he 

 studied the ice of the interior, the so-called "icebhnk." There 

 we find a continent not less in extent than the whole Scandina- 

 vian peninsula, covered with an ice-crust 1,000 feet in thickness, 

 moving from the interior towards the west coast. This mass 

 of ice, laden with stone blocks, advances slowly but steadily 

 towards the west coast, where it breaks up into large fragments, 

 which, in the form of icebergs, often of colossal dimensions, 

 are carried by the sea currents in definite directions, even to the 

 Azores. They gradually melt, and deposit their freight at the 

 bottom of the sea. 



The same phenomenon formerly occurred in Norway, Sweden, 

 and Finland. The country lay shrouded beneath an enormous 

 ice-mass, which carried its substratum of pebbles and gravel 

 into the sea. The whole rocky mass of Norway was polished 

 and grooved, but the frozen sea, which surrounded this pre- 

 historic Greenland, stood at a lower level than at present, for 

 in many places the dragged surfaces stretch far out beneath the 

 present sea-level. Though this circumstance alone may not be 

 sufiicient to explain the refrigeration of the northern continent 

 to the same degree as that of Greenland, the greater elevation 

 of the land above the sea may have contributed to it. When- 

 ever the tracts of the glaciers show beneath the present sea- 

 level, the waters must have been lower, for the ice is melted 

 and undermined by them, as shown by the polar glaciers at 

 ebb tide. 



The sea rose, the land became warmer, the ice-shroud melted, 

 the highest ridges showed their pinnacles, the ice broke into 

 separate glaciers, which continued to fill up the valleys. Now 

 we find moraines as in our present glaciers ; medial and terminal 

 moraines ; walls, the extremities of which now stretch towards 



