ICE AND GLACIERS. 131 



distinguished from those which water has rolled down, 

 by their enormous magnitude, by the perfect retention 

 of all their edges which are not at all rounded off, and 

 finally by their being deposited on tlie glacier in exactly 

 the same order in which the rocks of which they formed 

 part stand in the mountain ridge ; while the stones 

 which currents of water carry along are completely 

 mixed together. 



From these indications, geologists have been able to 

 prove that the glaciers of Chamouni, of Monte Eosa, 

 of the St. Grotthard, and the Bernese Alps, formerly 

 penetrated through the valley of the Arve, the Rhone, 

 the Aare, and the Ehine to the more level part of 

 Switzerland and the Jura, where they have deposited 

 their boulders at a height of more than a thousand feet 

 above the present level of the Lake of Neufchatel. 

 Similar traces of ancient glaciers are found upon the 

 mountains of the British Islands, and upon the Scan- 

 dinavian Peninsula. 



The drift-ice too of the Arctic Sea is glacier ice ; it 

 is pushed down into the sea by the glaciers of Grreenland, 

 becomes detached from the rest of the glacier, and floats 

 away. In Switzerland we find a similar formation of 

 drift-ice, though on a far smaller scale, in the little 

 Marjelen See, into which part of the ice of the great 

 Aletsch Glacier pushes down. Blocks of stone which lie 

 in drift-ice may make long voyages over the sea. The vast 

 number of blocks of granite which are scattered on the 

 North G-erman plains, and whose granite belongs to the 

 Scandinavian mountains, has been transported by drift- 

 ice at the time when the European glaciers had such an 

 enormous extent. 



I must unfortunately content myself with these few 

 references to the ancient history of glaciers, and re- 

 vert now to the processes at present at work in them. 



7 



