ne's theory of barriers of detritus, though I could help
him in one way--viz., by the soundings which occur at the entrances of
the deepest fiords in T. del Fuego. I do not think he gives the smallest
satisfaction with respect to the successive and comparatively sudden
breakage of his many lakes.

Well, I enjoyed my trip to Glen Roy very much, but it was time thrown
away. I heartily wish you would go there; it should be some one who
knows glacier and iceberg action, and sea action well. I wish the Queen
would command you. I had intended being in London to-morrow, but one of
my principal plagues will, I believe, stop me; if I do I will assuredly
call on you. I have not yet read Mr. Milne on Elevation (522/11. "On
a Remarkable Oscillation of the Sea, observed at Various Places on the
Coasts of Great Britain in the First Week of July, 1843." "Trans. R.
Soc. Edinb." Volume XV., page 609, 1844.), so will keep his paper for a
day or two.

P.S.--As you cannot want this letter, I wish you would return it to me,
as it will serve as a memorandum for me. Possibly I shall write to Mr.
Chambers, though I do not know whether he will care about what I think
on the subject. This letter is too long and ill-written for Sir J.
Clark.

LETTER 523. TO LADY LYELL. [October 4th, 1847.]

I enclose a letter from Chambers, which has pleased me very much (which
please return), but I cannot feel quite so sure as he does. If the
Lochaber and Tweed roads really turn out exactly on a level, the sea
theory is proved. What a magnificent proof of equality of elevation,
which does not surprise me much; but I fear I see cause of doubt, for
as far as I remember there are numerous terraces, near Galashiels, with
small intervals of height, so that the coincidence of height might be
cooked. Chambers does not seem aware of one very striking coincidence,
viz., that I made by careful measurement my Kilfinnin terrace 1202 feet
above sea, and now Glen Gluoy is 1203 feet, according to the recent more
careful measurements. Even Agassiz (523/1. "On the Glacial Theory," by
Louis Agassiz, "Edinb. New Phil. Journ." Volume XXXIII., page 217, 1842.
The parallel terraces are dealt with by Agassiz, pages 236 et seq.)
would be puzzled to block up Glen Gluoy and Kilfinnin by the same
glacier, and then, moreover, the lake would have two outlets. With
respect to the middle terrace of Glen Roy--seen by Chambers in the Spean
(figured by Agassiz, and seen by myself but not n