Prof. Siruder on Boivlders. 329 



rally received explanation of Saussure and Escher, that it is by 

 the pressure of snow on the heights falling down, to be unten- 

 able, still we are justified in asking for analogies, in the coun- 

 tries where the state of things, which they assume, actually ex- 

 ists. If it requires a fall of temperature of only 6° at the highest 

 in order to secure the forming of glaciers at the foot of the higher 

 snow mountain ranges, why do so many Alpine valleys, whose 

 annual temperature falls below the requisite degree remain desti- 

 tute of them ? Why is not the Altai entirely encircled with ice, 

 where the temperature of the surrounding lowland scarcely rises 

 above 1° ? W hy hear we not of such colossal glaciers and im- 

 mense plains in Scandinavia and Greenland covered several thou- 

 sand feet entirely with ice ? Why are not Chamouni, Latschthal, 

 Bagne, fcc, filled with glaciers ? Manifestly the origination of 

 glaciers is not dependant solely on the relations of temperature ; 

 there appears also to be required in order to its being filled with 

 glaciers, a depth and breadth of the valley fixed in relation to the 

 height of the adjacent snow mountain range, which ought not to 

 be passed over. This simple remark must at once have forced 

 itself upon geologists, so well acquainted with the Alps as those 

 who have attempted to establish the new theory ,• and, apparently 

 in order to meet this objection, Hr. v. Charpentier thought it ne- 

 cessary to make the lowering of the mean temperature cotempo- 

 raneous with a considerable elevation of the mountain range, in 

 which however, it has not become clear to me, how it is consis- 

 tent that the land should be powerfully swollen by internal heat, 

 and at the same time while this higher heat is streaming out, cover 

 itself with ice ? Granting, meanwhile, the possibility of such a 

 state of things, inasmuch as no rise of annual temperature is 

 reported of Scandinavia at the present time in the process of ele- 

 vation, we are obliged again to inquire, here too, after analogies, 

 and the Himalaya at once offers itself to us as a mountain range, 

 which might well be likened to elevated Alps. This lies, to be 

 sure, 15° farther south than the Alps, but its summits con- 

 siderably exceed the height, (about 20,000 feet,) which H. v. 

 C. rec[uires for the loftiest Alpine top in the diluvial era, and in 

 still stronger contrast does the elevation of its valley-bottoms 

 and plateaux surpass that (5 or 6000 feet) to which the valley- 

 bottom of Switzerland ought according to the theory to have 

 been raised at that time. The state of things of the one m.oun- 



Vol. XXXVI, No. 2— April-July, 1839. 42 



