To Charles Lyell 14 October 1
Down. | Bromley. | Kent. S.E.
My dear Lyell
I return Jamieson’s capital letter.2 I have no comments, except to say that he has removed all my difficulties & that now & for ever more I give up & abominate Glen Roy & all its belongings.— It certainly is a splendid case & wonderful monument of the old Ice Period.—3 You ought to give a woodcut.—4 How many have blundered over those horrid shelves!5
That was a capital paper by Jamieson in last G. Journal:6 I was never before fully convinced of the land glacialisation of Scotland before; though Chambers tried hard to convince me.—7
I must say I differ rather about Ramsay’s paper;8 perhaps he pushes it too far. It struck me the more from remembering some years ago marvelling what cd be the meaning of such a multitude of Lakes in Finland & other northern districts. Ramsay wrote to me & I suggested that he ought to compare mountainous Tropical regions with Northern regions.— I could not remember many lakes in any mountainous Tropical country.9 When Tyndall talks of every valley in Switzerland being formed by glacier, he seems to forget there are valleys in the Tropics;10 & it is monstrous in my opinion the accounting for glacial period in Alps by greater height of mountains, & their lessened heights, if I understand, by glacial erosion.—11 Ne sutor ultra crepidam, I think applies in this case to him.—12 I am hard at work on “Variation under Domestication”.13
Ever yours | C. Darwin
P.S. I am rather overwhelmed with letters at present, & it has just occurred to me that perhaps you will forward my note to Mr Jamieson; as it will show that I entirely yield. I do believe every word in my Glen Roy paper is false— [Enclosure]14 Ellon, Aberdeensh. 15, Aug. 1862 My Dear Sir Charles,
I have been again at Lochaber this summer, and have come away more convinced than ever of my last years views of the Glen Roy Lakes. I made a careful measurement with a good spirit level of the height of the lowest line near the mouth of Glen Roy and make it 854 feet above the mean sea level—starting from an advance mark at Bridge of Roy. Another measurement I made about six miles east—up Glen Spean—indicates a rise of about a foot in the mile fully in the line as you go east. Circumstances prevented me getting to the E. end of L. Laggan, but I hope to get there at some future time— meanwhile my recollection of that locality leads me to think that this slight elevation to Eastward will be borne out there also—
The Glen Arkaig glacier has been the main agent in blocking up Glen Gluoy & the mouth of Glen Spean but has been aided in the latter case by the neighbouring ice streams in particular by one from the longest corry on the N. flank of the Ben Nevis ridge called Corry N. Youn.15
I also discovered the most beautiful set of moraines that I believe will be found in the United Kingdom.!
Good instances of Moraines have been always a desiratum in this country but I think these will satisfy everybody that sees them. They are the work of the old Glen Treig glacier but at such a distance from the mouth of the glen as to have eluded the observation of former visitors. I noticed part of them from the shoulder of a hill last year & it was one of my objects this season to revisit them— They have a sweep of several miles, forming a sort of huge semi circle—tier within tier—in many places almost as regular as a railway embankment— the inner one is composed in many parts wholly of large blocks of syenite, often from 10 to 15 feet in length, without the intermixture of earthy matter, which makes it very striking— these have been pushed by the glacier before it in certain places off the syenitic mass up hill & left upon the gneiss on the N. side of Glen Spean— The retreat of the ice has left a smooth space like a bay within these moraines almost free of blocks—
These moraines are as fine a sight as the Glen Roy lines themselves & to a geologist— as interesting. their fine preservation is certainly a treat.
—Another object of my visit as you are aware was to ascertain the relation of the Glen Roy lakes to the great submergence— with this view I examined the lower part of Glen Nevis which as it opens out upon an arm of the sea I thought most suitable to throw light upon the question— The result was that nothing appeared to indicate that Glen Nevis had been occupied by the sea since the glacier left it— The moranic hillocks even at its mouth seem to have remained undisturbed by any marine action, with this exception, that the great 40 foot terrace of the West Coast can be distinctly traced up to the mouth of the glen and apparently extending across it up to Bannavie16 & fringing the bottom of the moranic heaps with a flat surface of shingle— This would seem to place the Glen Roy glacier lake period after the great submergence and before the era of the 40 foot old coast line of Argyleshire— This was what I expected— But I don’t know how to reconcile it with Chamber’s account of the Glen Iorsa moraine in Arran being slung over upon the old beach for I should think the Glen Nevis glacier would have protruded longer than most others in Scotland17
—Half a mile below Fort William I discovered a famous section of this old 40 foot terrace or ancient coast line— its height at the mouth of Glen Nevis is 40— or 43 feet above the mean sea-level— this section contained a bed of shells—some of which are arctic— an hour or twos search yielded me the following;
Modiola modiolus— abundant
Astarte elliptica— numerous
[ditto] compressa 4 specimens
Pecten opercularis several
Nucula. 1. app. N. nucleus–
Pilidium fulvum. a few
Anomia ephippium several
Puncturella noachina 2.
Trophon clathratus numerous
[ditto] scalariforme. 1. imperfect
Lacuna vincta. numerous
Littorina expansa several
(Lochus expansus, Brown & Smith)
[ditto] littorea 1. large specimen
[ditto] rudis 5. some of these perhaps young of L. littorea
Natica clausa 8. or 9.
Trochus cinerarius several
[ditto] tumidus 2. or 3.
Buccinum undatum. a few broken
Bela trevelliana. 1. specimen
Bela. undetermined sp. 7.
Rissoa striata. 2.
Chiton. fragment of a large species
Echinus. some plates & spines
The prevalence of Littorinæ & Lacuna are good evidence of a coast or shore line— the shells seemed to have been mostly all dead ones, several of them are pierced by a boring mollusk—. all the species range into shallow water except the Puncturella, Pilidium, & Nucula, which are in small numbers and had been drifted— we often get such thrown up on our coast here—
The prevailing littorina was as you see the Arctic variety of L. littoralis— and all the naticus were N. clausa.
This would seem to shew that the arctic shells lingered in our seas till a later period than has been hitherto supposed.
In 1860 I found at Otter ferry at Loch Fyne just a little above high water mark a sandy clay with shells which I am inclined to think may also belong to this 40 feet old coast line as the group was so similar to those at Fort William— & I half suspect the shelly bed in the Kyles of Bute may also belong to it & also those got at Loch Lomond wh. would embrace many of Jordanhill’s arctic clyde species—18 The species I got at Otter were.
Tellina proxima— not of large size—several
Astarte compressa— 1. complete
Cardium. small species
Saxicava arctica.. 1. valve of large variety
Mya truncata several
Pildium fulvum. 3.
Littorina littoralis. 2. or 3.
[ditto] rudis. 1. or 2
[ditto] littorea. 1. or 2. small
Trochus cinerarius. 1. small
Marganta undulata. 1. damaged
Trophon clathratus. 1.
Lacuna vincta. 2.
Echinus. a few plates & spines.
I think it is evident that the Glen Nevis glacier must have extended down further than this section at Fort William when that of Glen Treig or Glen Arkaig were so much developed. so this shell bed must be later than that period— the glaciers from Ben Lomond I think wd. have also prevented the accumulation of any shelly beds along Loch Lomond & wd. have destroyed previous ones— ditto probably at Kyles of Bute—
But if the elevation has increased a foot in the mile from W to E. as I have hinted this 40 feet terrace of the West coast would correspond to beds of greater elevation on the east— so that it is probably older than the 25. to 30 foot raised beaches at Falkirk. Forth, &c.
—The undetermined species of Bela or Mangelia which I got in this Fort William section seems different from any British species in Forbes & Hanley—19 neither can I find any agreeing with it in Searles Woods Crag Mollusca.20
—I enclose a drawing of it— It a good deal resembles the Fusus proprinquus in miniature. but with the canal less produced. I wd. take it very kind if you could give me any hint of what it is.
I am very ill off for books on Arctic shells with good figures— Wood’s Crag Mollusca is almost my sole refuge. I have searched the Catalogues of the Geol. Soc. library21 but cannot find Gould’s Report on the Invertebrata of Massachusetts. 22 nor. Moller23 nor Middendorf24 nor Loven.25 nor any other. I think the Council shd. get some of these for the use of members
—There will be a parcel of books sent to me from the library in a few days— if you could lend me a look of Gould’s Report if you have it, it would be a great favour & could be sent in my parcel by Mr. Jones.26
I enclose a little map shewing the disposition of the Glen Treig Moraines & the direction of the glacial striæ in Glen Arkaig &c. & position of shelly section of old coast line near Fort William.
The sloping terraces which Darwin had a difficulty about in the lower part of Glen Spean I believe to have been accumulated in a lower lake retained by the protrusion of the Glen Nevis glacier after that of Glen Arkaig had shrunk out of the mouth of Glen Spean— His buttresses or terraces above the highest line near the outfalls I believe to be of the nature of side moraines or moraine matter accumulated in lateral pools between the ice & the hill at a period antecedent to the lakes—27 It would oblige me if you would shew him this communication if you think he would be interested in it.
Please excuse the haste in which I have had to write the above & believe me to be | with the greatest respect & esteem | Your very obed. servt. | Thos. F. Jamieson.
Sir. Charles Lyell. FRS
P.S. Mr R. Chambers had some word of perhaps going to Lochaber in Sept. if you should see him you might tell him of these moraines as I have no doubt he wd. like to see them if he goes.28
[DIAG HERE] Shell smooth, white, rather thin, of about six turns, outer lip thin; spin tapering, apex rather obtuse; volutions slightly convex— traces of spiral striæ on the base of the shell & some irregular slight plications on the 3rd. & 4.th turns.
[DIAG HERE] Moraines marked by green curving lines— arrows mark direction of glacial scores + position of section of coast line. tract of syenite. Lake.29
Further comments on Jamieson’s theory of the formation of the roads of Glen Roy; paper by Jamieson dealing with glaciation in Scotland ["On the ice-worn rocks of Scotland", Q. J. Geol. Soc. Lond. 18 (1862): 164–84].
Comments on paper by A. C. Ramsay on the glacial formation of lakes ["On the glacial origin of certain lakes", Q. J. Geol. Soc. Lond. 18 (1862): 185–204].
Criticises remarks by John Tyndall on glacial formation of Swiss valleys.
- Letter no.
- Darwin, C. R.
- Lyell, Charles
- Sent from
- Source of text
- American Philosophical Society (267), Edinburgh University Library (Gen. 112/2840–3)
- Physical description
- 5pp encl 9pp sketch
Please cite as
Darwin Correspondence Project, “Letter no. 3761,” accessed on 25 February 2017, http://www.darwinproject.ac.uk/DCP-LETT-3761