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Darwin Correspondence Project

To William Crawford Williamson   31 January [1848]

Down Farnborough Kent

Jan 31st

My dear Sir

I am extremely much obliged to you for your kind present of your work,1 which I got two days ago from the Geolog. Society. I have read it half through, & have been greatly interested by it. It is a most curious & admirable subject, & one on which I am very glad to acquire some little information. You mention the frondescent incrustation at Ascension: do you care to have specimen for microscopical examination: I have described it in detail in my volume on Volcanic Islands.—2

Permit me to suggest to you a most careful examination of the beds, under-clay shale &c associated with the Coal.3 Geology presents scarcely any more perplexing & certainly no more interesting problem than the formation of the coal. It has occurred to me that careful microscopical examination might reveal infusoria, & show whether the intervening beds were deposited under the sea, or brackish, or freshwater:—this question settled, wd be a great point gained.4

Once more I thank you for your volume, to the finishing of which I look forward with pleasure.

Believe me | dear Sir | Yours very faithfully | C. Darwin


Williamson 1847. The paper had been read on 4 November 1845 but was subsequently considerably enlarged. The copy sent to CD was a separate advance printing, dated 1847 (Darwin Library–Down). The final version was published in the Memoirs of the Literary and Philosophical Society of Manchester, 2d ser. 8 (1848): 1–128.
Volcanic islands, pp. 50–4.
For Williamson’s earlier work on the origin of coal see Williamson 1842.
CD had earlier expressed the hope that Christian Gottfried Ehrenberg would examine coal for Infusoria (see letter to J. D. Hooker, [12 May 1847]).


Volcanic islands: Geological observations on the volcanic islands, visited during the voyage of HMS Beagle, together with some brief notices on the geology of Australia and the Cape of Good Hope. Being the second part of the geology of the voyage of the Beagle, under the command of Capt. FitzRoy RN, during the years 1832 to 1836. By Charles Darwin. London: Smith, Elder & Co. 1844.

Williamson, William Crawford. 1842. On the origin of coal. Report of the 12th meeting of the British Association for the Advancement of Science held at Manchester. Transactions of the sections, pp. 48–9.

Williamson, William Crawford. 1847. On some of the microscopical objects found in the mud of the Levant, and other deposits; with remarks on the mode of formation of calcareous and infusorial siliceous rocks. Privately printed. Manchester. Reprinted in Memoirs of the Literary and Philosophical Society of Manchester 2d ser. 8 (1848): 1– 128. [Vols. 3,4]


Thanks WCW for his article ["Microscopical objects found in mud of Levant", Mem. Lit. & Philos. Soc. Manchester 2d ser. 8 (1848):1–128]. Comments on it; offers to send Ascension Island specimens. Urges WCW to re-examine coal-beds for Infusoria to determine whether intervening beds were deposited by sea-, brackish, or fresh water.

Letter details

Letter no.
Charles Robert Darwin
William Crawford Williamson
Sent from
Source of text
Kobunso (Mr Sorimachi, bookseller, Tokyo)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1149,” accessed on 18 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 4