here 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
border them, and the boulders from the hill-sides 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 hills. This being the case,
let us examine a little more closely the local phenomena connected with
the ancient extension of glaciers in this region, and especially the
parallel roads of Glen Roy.

[Illustration:

G. R. Glen Roy.
M. Moeldhu Hill.
S. Spean River.
G. S. Glen Spean.
L. Loch Laggan.
T. Loch Treig.
G. Glen Gloy.
L. O. Loch Lochy.
A. Loch Arkeig.
E. Loch Eil.
N. Ben Nevis.
1,2,3. The three parallel roads.]

Among the Grampian Hills, a little to the northeast of Ben Nevis, lies
the valley of Glen Roy, a winding valley trending in a northeasterly
direction, and some ten miles in length. Across the mouth of this
valley, at right angles with it, runs the valley of Glen Spean, trending
from east to west, Glen Roy thus opening directly at its southern
extremity into Glen Spean. Around the walls of the Glen Roy valley run
three terraces, one above the other, at different heights, like so many
roads artificially cut in the sides of the valley, and indeed they go by
the name of the "parallel roads." These three terraces, though in a less
perfect state of preservation, are repeated for a short distance at
exactly the same levels on the southern wall of the valley of Glen
Spean, just opposite the opening of the Glen Roy valley; that is, they
make the whole circuit of Glen Roy, stop abruptly, on both sides, at its
southern extremity, and reappear again on the opposite wall of Glen
Spean. I should add, however, that all three do not come to this sudden
termination; for the lowest of these terraces turns eastward into the
valley of Glen Spean, following the whole curve of the eastern half of
the valley, while, of the two upper terraces, there is no trace