150 NEWER PLIOCENE PERIOD. [Ch. XI. 



might produce in this region, if the peaks or < needles,' as they 

 are called, of Mont Blanc were shaken as rudely as many parts 

 of the Andes have been in our own times. The glaciers 01 

 Chamouni would immediately be covered under a prodigious 

 load of rocky masses thrown down upon them. Let us, then, 

 imagine one of the deep narrow gorges in the course of the 

 Arve, between Chamouni and Cluse, to be stopped up by the 

 sliding down of a hill-side (as the Rossberg fell in 1806 *), 

 and a lake would fill the valley of Chamouni, and the lower 

 parts of the glaciers would all be laid under water. The 

 streams which flow out of arches, at the termination of each 

 glacier, prove that at the bottom of those icy masses there are 

 vaulted cavities through which the waters flow. Into these 

 hollows the water of the lake would enter, and might thus 

 float up the ice in detached icebergs, for the glaciers are much 

 fissured, and the rents would be greatly increased during a 

 period of earthquakes. Icebergs thus formed might, we con- 

 ceive, resemble those seen by Captain Scoresby far from land 

 in the Polar seas, which supported fragments of rock and soil, 

 conjectured to be above fifty thousand tons in weight f. Let 

 a subsequent convulsion, then, break suddenly the barrier of 

 the lake, and the flood would instantly carry down the icebergs, 

 together with their burden, to the low country at the base of 

 the Alps. 



We have stated in the first volume that blocks conveyed on 

 floating icebergs must be deposited in different parts of the 

 bottom of the ocean, in whatever latitudes those icebergs are 

 dissolved J . 



European alluviums in great part tertiary. If those writers 

 who speak of an ' alluvial epoch ' intend merely to say that a 

 great part of the European alluviums are tertiary ', we fully coin- 

 cide in that opinion, for the map of Europe, given in our 

 second volume, will show that almost every part of the existing 

 continent of Europe has emerged from beneath the waters 



* See above, vol. ii. 1st Ed., p. 229 ; 2d Ed. p. 235. 

 t See above, vol. i. p. 299, 1st Ed.j p. 342, 2d Ed. J Vol. i. ibid. 



