56 
THE PARALLEL ROADS OF 
peared or retreated to the mountain-heights ? 
The wasting ice must have occasioned immense 
freshets, the action of which we shall trace 
hereafter, when examining the formation of 
our drift-ponds, of our river-beds and estuaries, 
as well as the river-terraces standing far above 
the present water level. 
And now, if it be asked how much of this 
evidence for the former existence of glaciers is 
to be found in Great Britain, I answer, that 
there is not a valley in Switzerland where all 
these traces are found in greater perfection 
than in the valleys of the Scotch Highlands, 
or of the mountains of Ireland and Wales, 
or of the lake-region in England. Not a link 
is wanting to the chain. Polished surfaces, 
traversed by striae, grooves, and furrows, with 
a sheet of drift resting immediately upon them, 
extend throughout the realm, — the roches 
moutonnees raise their rounded backs from the 
ground there as in Switzerland, — transverse 
moraines bar their valleys and lateral ones bor¬ 
der them, and the boulders from the hillsides 
are scattered over the plains as thickly as 
between the Alps and the Jura, and are here 
and there perched upon the summits of isolated 
