GEOLOGY. 573 



races succumbed and were buried beneath this grim wind- 

 ing-sheet ; a luminary dim and pale alone lighted up these 

 lifeless solitudes, and the silence of death reigned every- 

 where. 



What was the first cause of these unexpected phenomena 

 of this period, justly called the glacial, which swept over 

 the globe, formerly so heated ? It will perhaps long re- 

 main unknown, but its ravages have left everywhere in- 

 delible traces. The waves of this immense sea of ice, roll- 

 ing down the mountains, tore off the projecting portions, 

 bore them away in their movement, and scattered them 

 everywhere on their passage. In this way numerous frag- 

 ments from the loftiest peaks of Scandinavia were trans- 

 ported to the plains of Germany and Novogorod ; others, 

 violently torn away from the summits of the Alps, were 

 strewed over the slopes of Jura. 



Up to the present time geologists had supposed that these 

 fragments of rocks, these erratic blocks, as they are called, 

 which are met with far from the mountains of which, as 

 their structure shows, they once formed part, were trans- 

 ported by the violent action of the waters, and that they 

 had been carried away by the waves of deluges. Agassiz, 

 in his work on " Glaciers," has shown that this hypothesis 

 is inadmissible, and that to the great movements of the 

 seas of ice must be attributed the transport of rocks which 

 we often find far from the spot where they were formed. 



It is to this severe cold, which prevailed over a large part 

 of Europe, that we must refer the great hecatomb of those 

 myriads of elephants, mastodons, and rhinoceroses, which 

 formerly lent life to every part of France, Germany, and 



