quent da 



°ice. 



ous 



% 



1 



5 soiik, 



s °metiD] 



t 



r S e glad 



8 l «Clf; 



>e 



compart 



7 the 



w 



nosities i 



n-essiontt 

 (I slowest 

 icier raoti 

 iscous hok 



alion 



land, it t 



entire m 



the gem 

 summer, 



r the tlK 



t is 



lb) 

 pens 



final 



r the I 



that 



the * 

 ve r dra'»' 

 locks fil 



[0 



jntaio 



si<p 



a= 



it ^ 



often *■ 



of 1 ' 



ice 



o« 



niW 



es 



do* 11 



the" 



GLACIERS. 



3 



Upper 

 Gallery. 



of glaciers ai*e seamed by crevasses, or small and large cracks 



partly caused by the passage of the ice over the unequal floors 



of the valleys. Into these, stones from the surface frequently in Recess 41. 



fall, and mud and other fine sediments are washed into 



them by running water that, during the heats of summer, 



often forms actual brooks upon the ice. These find their 



way to the bottom of the moving masses, and the finer 



siliceous and other materials, acting like emery powder 



between the 



moving 



ice and its rocky floor, grind off 

 asperities, and smooth and polish the surface, often 

 giving to it largely rounded and mammillated contours, 

 termed by the French and Swiss roches moutonnees. The 

 stones and larger blocks fixed between the ice and the rocky 

 bottom scratch and groove these surfaces, such lines neces- 

 lnd Huxlf sarily running in the direction of the flow of the glaciers, or 

 (ue to a 71 m other words, of the trend of the valleys. The imprisoned 

 f the tern stones also, themselves become scratched and grooved in their 



onward passage. When, through changes of climate, glaciers 

 have decreased in size, they have often left lateral moraines 

 high on the sides of the mountains, and terminal moraines 

 at points far below the existing extremities. In many of 

 the valleys of Switzerland, the Himalaya, &c, roches 

 moutonnees, and moraines are found far beyond the limits of 

 existing glaciers, and all the signs of glaciers often force 

 themselves on the notice in mountain regions where they 



have 



altogether disappeared, 



probably since the newer 

 These signs are roches mouton- 



often as perfect as those that fringe the sides 



Pliocene or glacial epoch. 



nees, often covered with ice-borne boulders ("blocs perches"), 



scratched, striated, and grooved surfaces, and numerous 



moraines, 



and ends of existing Alpine glaciers. Appearances of the 

 kind adverted to are frequent in the mountains of the 

 Vosges, Ireland, the Highlands of Scotland, and Wales; 

 and specimens derived from the moraines of the Alps, the 

 Vosges, and Wales are deposited in this case. 



A 2 





