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Darwin Correspondence Project

To W. H. Fitton1   23 June 1842

[Capel Curig, N. Wales]

23 June 1842

“Yesterday (and the previous days) I had some most interesting work in examining the marks left by extinct glaciers—2 I assure you no extinct volcano could hardly leave more evident traces of its activity and vast powers. I found one with the lateral moraine quite perfect which Dr. Buckland did not see— Pray, if you have any communication with Dr. Buckland give him my warmest thanks for having guided me, through the published abstract of his Memoir,3 to scenes, and made me understand them, which have given me more delight, than I almost remember to have experienced since I first saw an extinct crater   The valley about here, and the Inn at which I now am writing must once have been covered by at least 800 or 1000 feet in thic⁠⟨⁠kness⁠⟩⁠ of solid Ice!— Eleven years ago, I spent a whole day in the valley,4 where yesterday every thing but the Ice of the Glacier was palpably clea⁠⟨⁠r⁠⟩⁠ to me, and I then saw nothing but plain water and bare roc⁠⟨⁠k.⁠⟩⁠

These glaciers have been grand agencies: I am the more pleased with what I have seen in N. Wales, as it convinces me, that my views, of the distribution of the boulders on the S. american plains, has been effected by floating Ice are correct.5

I am also, more convinced that the valleys of Glen Roy and the neighbouring parts of Scotland have been occupied by arms of the sea,6 and very likely (for on that point I cannot of course doubt Agassiz & Buckland) by glaciers also.”

C. Darwin


The text of the extract is published in E. C. Agassiz 1885, 1: 342–3, where the recipient is mistakenly identified as ‘Dr Tritten’. A copy was enclosed in a letter to Louis Agassiz from William Buckland, dated 22 July 1842. According to Buckland, it ‘was communicated to me by Dr. [Fitton], during the late meeting [of the British Association] at Manchester, in time to be quoted by me versus Murchison, when he was proclaiming the exclusive agency of floating icebergs in drifting erratic blocks and making scratched and polished surfaces’ (E. C. Agassiz 1885, 1: 342).
CD explored glacial sites in North Wales 18–28 June 1842 (‘Journal’; Correspondence vol. 2, Appendix II). Notes made during the trip are in DAR 27.1, together with a draft of his article on ‘Notes on the effects produced by the ancient glaciers of Caernarvonshire’ (Collected papers 1: 163–71).
CD refers to his geological tour with Adam Sedgwick in August 1831.
See ‘On the distribution of the erratic boulders and on the contemporaneous unstratified deposits of South America’ (Collected papers 1: 145–63).


Agassiz, Elizabeth Cary. 1885. Louis Agassiz: his life and correspondence. 2 vols. London: Macmillan and Company.

‘Ancient glaciers of Caernarvonshire’: Notes on the effects produced by the ancient glaciers of Caernarvonshire, and on the boulders transported by floating ice. By Charles Darwin. Philosophical Magazine 3d ser. 21 (1842): 180–8. [Shorter publications, pp. 140–7.]

Buckland, William. 1841. On the glacia-diluvial phænomena in Snowdonia and the adjacent parts of North Wales. [Read 15 December 1841.] Proceedings of the Geological Society of London 3 (1838–42): 579–88.

Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

‘Parallel roads of Glen Roy’: Observations on the parallel roads of Glen Roy, and of other parts of Lochaber in Scotland, with an attempt to prove that they are of marine origin. By Charles Darwin. [Read 7 February 1839.] Philosophical Transactions of the Royal Society of London 129: 39–81. [Shorter publications, pp. 50–88.]


[Excerpt copied from a letter CD wrote to WHF.]

CD’s gratefulness to William Buckland for his guidance on the glaciated terrain of N. Wales. "I am also convinced that the valleys of Glen Roy … have been occupied by arms of the Sea, & very likely, (for on that point I cannot of course doubt Agassiz & Buckland) by glaciers also."

Letter details

Letter no.
Charles Robert Darwin
William Henry Fitton
Sent from
Source of text
Houghton Library, Harvard University (Louis Agassiz correspondence and other papers, MS Am 1419: 239)
Physical description
C 1p

Please cite as

Darwin Correspondence Project, “Letter no. 632,” accessed on 27 May 2024,

Also published in The Correspondence of Charles Darwin, vol. 2