VI MOUNTAINS 231. 
occupied by another which filled the basin 
of the Lago Maggiore ; a third occupied the 
valley of the Dora Baltea, and has left a 
moraine at Ivrea some twenty miles long, and 
which rises no less than 1500 feet above the 
present level of the river. The Scotch and 
Scandinavian valleys were similarly filled 
by rivers of ice, which indeed at one time 
covered the whole country with an immense 
sheet, as Greenland is at present. Hnor- 
mous blocks of stone, the Pierre a Niton 
at Geneva and the Pierre 4 Bot above 
Neuchatel, for imstance, were carried by 
these glaciers for miles and miles; and many 
of the stones in the Norfolk cliffs were 
brought by ice from Norway (perhaps, how- 
ever, by Icebergs), across what is now the 
German Ocean. Again wherever the rocks 
are hard enough to have withstood the 
weather, we find them polished and ground, 
just as, and even more so than, those at the 
ends and sides of existing glaciers. 
The most magnificent glacier tracks in the 
Alps are, in Ruskin’s opinion, those on the 
rocks of the great angle opposite Martigny ; 
