THE GLACIAL THEORY. 



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glacier, composed of gravel stones cemented by ice, by 

 which the influence of the heat has been lessened, and whilst 

 the surrounding glacier has melted in a greater or less degree, 

 has preserved those portions in which they occurred. We 

 also learn that large cavities or hollows exist beneath most 

 glaciers, by which numerous torrents find ready exit from 

 the superincumbent glacial beds, and more elevated regions. 



PART III. 



On the theory of glacial action ; luiih especial reference to the extended 

 system of Mons. Agassiz. 



Present increase in the extent of glaciers. 



" The lovv^er glacier of the Aar has increased a distance of nearly a mile 

 since 1811; the 'glaciers of Grindelwald increase "visibly in size; the 

 glacier of Zermatt has increased in size on its left flank ; the upper glacier 

 of the Aar decreases whilst the lower glacier of the same locality increases 

 in extent." Agassiz. 



" The number and extent of glaciers is \Qry considerable ; from Mont 

 Blanc to the borders of the Tyrol, there are reckoned about 400 glaciers, 

 some only three miles in length, whilst the greatest number range from 

 10 to 15 miles." Pen. Cyclop. Art. " Glaciers.^' 



Moraines formed by glaciers which have retrograded. 



" A great moraine occurs in the valley of Kander ; termed the moraine 

 of Kandersteg." Guyot. 



**The huts composing the small -village of Gieta in the valley of Mount 

 Joie in Savoy, are built between three ancient moraines, which were 

 formed by the glacier of Trelatete at that point ; this same glacier in 

 1821, was 7,000 feet distant from those moraines." Venetz. 



'* The glacier of Salenaz in the valley of Ferrat in Valais, has left on 

 the right hand side, an enormous moraine, which is now 8,000 feet 

 distant from the extremity of the glacier." Venetz. 



*'The httle \dllage of x\n-der-Eggen is situated upon one of these 

 ancient moraines, the last of a series, distant 7,000 feet from the glacier." 

 Venetz. 



" The glacier of Sirwolten has deposited on the left side, below the 

 hospital of the Simplon, three moraines, which are now more than a 

 league distant from the glacier." Venetz. 



** The villages of Ried, Bodmen, and Halten, in Haut Valais, are built 



