MR MILNE ON THE PARALLEL ROADS OF LOCHABER. 411 
are incorrect. (2.) That, assuming as true the facts stated by him, they still 
afford no evidence that glaciers existed in the Lochaber valleys. 
(1.) There are three main facts relied on by M. Acassiz. He states, First, 
That in Glen Roy, and in that part of Glen Spean, between Bridge of Roy and Loch 
Treig, there are 3 shelves visible ; Secondly, That these shelves all terminate, on 
both sides of the valley at or near the Bridge of Roy ; Third, That the bottom of 
Glen Spean, in front of Loch Treig, is not only polished with that polish charac- 
teristic of glaciers, but is, moreover, scratched transversely,—that is to say, at 
right angles to the direction of the valley, by a cause which evidently proceeded 
from Loch Treig. 
To explain these appearances, it is suggested, that ‘‘ the supposition of a 
ereat glacier descending from Ben Nevis, and shutting up the valley of the 
Spean, by resting on Moeldhu, which is opposite, combined with the influence 
of a glacier from Loch Treig, and which would bar the valley a second time at 
that height, would explain all the facts.” 
These facts, for an explanation of which this theory was invented, appear to 
me not to have been accurately observed. In the first place, the three shelves do 
not occupy, as M. Acassiz asserts, ‘‘ all the sinuosities of the lower part of Glen 
Spean, and of the whole of Glen Roy.” It is only the lowest of the three shelves, 
which occurs in Glen Spean and in the lower part of Glen Roy. The two upper- 
most shelves stop short of the mouth of Glen Roy, by about 2 miles; so that, if 
the Lake in Glen Roy was dammed back by a terminal moraine, that moraine 
could not have rested on Moeldhu, at the foot of Glen Roy; but must have been 
pushed up that valley, before the Ben Nevis glacier, 2 miles farther,—an opera- 
tion which the levels, distance, and direction of the valley would have rendered 
impossible. 
In the second place, the shelves do not, as M. AGassiz says, ‘‘ terminate at 
the same point,’’—viz., at Moeldhu, where he supposes the terminal moraine of 
the Nevis glacier to have been. The two uppermost shelves (as just stated) do 
not come within two miles of this point; and the lowermost shelf, instead of 
terminating there, runs, as formerly explained, several miles northwards, on both 
sides of the valley, towards Unachan, where they are4 miles apart. It is scarcely 
necessary to say, that a moraine in this low district, which is not connected with 
any Ben Nevis valley, and considering its required height and length, is incon- 
ceivable. 
In the third place, as to the existence of transverse scratches on the rocks in 
Glen Spean, which are said to indicate the movement of some body from Loch 
Treig, I could see no such scratches, though I twice surveyed the ground, and 
narrowly inspected the rocks, especially at the outlet from Loch Treig. Indeed, 
the supposition that any glacier flowed out of Loch Treig seems to be almost ex- 
cluded by the fact, that a shelf, perfectly horizontal, exists on both sides of the 
VOL. XVI. PART III. 5 M 
