Discusses his observations at Glen Roy. Mentions glaciers seen by Hooker in the Himalayas. Discusses problems of glacier–lake theory.
24 Oct 1861
My Dear Sir,
It would be unpardonable in me not to thank you for the valuable papers &c on Glen Roy which you have been so good as send me—
I found the locality so interesting & instructive that I hope to be able to pay
another visit to it. I saw Loch Spey from a distance standing
on the top of Tom Brahn, or rather endeavouring to stand, for
it was a gale like to blow the teeth out of one's head— Possibly the high
lying terraces or buttresses you refer to, may be explained by glacial action, for it
seems, from D
—The great sloping terraces at the mouth of Glen Spean I did not get examined, & am therefore unable to say much about, but if the ice-dam in that direction consisted of a glacier stream occupying the line of the Caledonian canal, great accumulations might be pushed into the dammed lake by short glaciers descending from the little hollows of Ben Nevis &c. & the hill streams of ditto
One of the greatest difficulties in the way of the glacier theory seems to me to arise from the supposition of the pressure of a column of water say 600 feet or so deep or more, being retained by an ice barrier. the glacier lakes of Switzerland seem to be retained chiefly by moraine matter, but in one case by ice alone— in the Himalaya near Karakorum pass also a large glacier lake—the largest I have heard of—seems to have been dammed by ice alone
I am | My Dear Sir | Yours very faithfully | Tho
C. Darwin Esq
- f1 3297.f1See letter to Charles Lyell, 20 October . Jamieson acknowledged CD's assistance in his published account of the parallel `roads' of Glen Roy (Jamieson 1863, p. 240). See also letter from T. F. Jamieson, 13 June 1861, letter to Robert Chambers, 30 April , and Correspondence vol. 9, Appendix IX.
- f2 3297.f2Jamieson made two visits to Lochaber, the first in August 1861 and the second in July 1862 (see Jamieson 1863, p. 240).
- f3 3297.f3The hill Tom Brahn (or Tombrahn) overlooks the head of upper Glen Roy (see Collected papers 1: 87 and the map in this volume, p. 248).
- f4 3297.f4Hooker 1854a, 1: 242--4; 2: 116--21. See also letter to J. D. Hooker, 28 September .
- f5 3297.f5Jamieson discussed the objections to postulating a former ice-dam in Glen Roy, and mentioned the glacier lakes of the Himalayas in his paper (Jamieson 1863, pp. 257--8).