nce, etc., but I suppose it is the consequence
of my paper being most tediously written. He gives me a just snub for
talking of demonstration, and he fights me in a very pleasant manner.
Now for business. I utterly disbelieve in the barriers (522/4. See note,
Letter 521.) for his lakes, and think he has left that point exactly
where it was in the time of MacCulloch (522/5. "On the Parallel Roads of
Glen Roy." "Geol. Trans." Volume IV., page 314, 1817 (with several maps
and sections).) and Dick. (522/6. "On the Parallel Roads of Lochaber."
"Trans. R. Soc. Edinb." Volume IX., page 1, 1823.) Indeed, in showing
that there is a passage at Glen Glaster at the level of the intermediate
shelf, he makes the difficulty to my mind greater. (522/7. See Letter
521, note.) When I think of the gradual manner in which the two upper
terraces die out at Glen Collarig and at the mouth of Glen Roy, the
smooth rounded form of the hills there, and the lower shelf retaining
its usual width where the immense barrier stood, I can deliberately
repeat "that more convincing proofs of the non-existence of the
imaginary Loch Roy could scarcely have been invented with full play
given to the imagination," etc.: but I do not adhere to this remark
with such strength when applied to the glacier-lake theory. Oddly, I was
never at all staggered by this theory until now, having read Mr. Milne's
argument against it. I now can hardly doubt that a great glacier did
emerge from Loch Treig, and this by the ice itself (not moraine) might
have blocked up the three outlets from Glen Roy. I do not, however, yet
believe in the glacier theory, for reasons which I will presently give.

There are three chief hostile considerations in Mr. Milne's paper.
First, the Glen [shelf?], not coinciding in height with the upper one
[outlet?], from observations giving 12 feet, 15 feet, 29 feet, 23 feet:
if the latter are correct the terrace must be quite independent, and the
case is hostile; but Mr. Milne shows that there is one in Glen Roy 14
feet below the upper one, and a second one again (which I observed)
beneath this, and then we come to the proper second shelf. Hence there
is no great improbability in an independent shelf having been found in
Glen Gluoy.

This leads me to Mr. Milne's second class of facts (obvious to every
one), namely the non-extension of the three shelves beyond Glen Roy; but
I abide by what I have written on that point, and repeat that if in Glen
Roy, wh