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]).

Manuscript Alterations and Comments

1.3 it.] above del ‘me.’
1.4 the] over ‘&’
2.3 the] interl

Please cite as “DCP-LETT-1149,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-1149