Ɛpsilon

To Charles Lyell   [24 January 1847]

Down

Sunday

My dear Lyell

I do not understand Mr Gould;1 the reef under water, I suppose is the “flat” of dead rock, often partically covered with water, separating the living margin of reef, from the islets, which Dr. Gould calls the Barrier.— I often refer to & have described it.— Tahiti is much less perfectly encircled than any other island of that group, but I consider it is encircled from Cooks chart,2 which has been copied into all the French Voyagers, who had some means of knowing whether it was incorrect.—

According to Cook (p 152 of my Book)3 the reef lies from 12 to 1 & 12 mile from shore (with profound water close outside) & with 10 to 30 fathoms within.—

On the side generally visited by shipping the reef is much broken. The Americans perhaps do not know of the submerged & probably dead part of the reef,4 encircling part of the island described in Nautical Magazine in 1836.;5 —& this is the part of the coast of Tahiti, where in Cooks chart, the Barrier is least perfect.— I did not colour it without consideration.—6

Hooker has been here a week & has been working at his Paper on Coal Plants7 & we have had much interesting conversation. He has been reading with more attention, he says, than he did before all Bunbury’s paper,8 & several times he has been expressing his admiration at them.

Ever yours | C. Darwin

1
Augustus Addison Gould, a personal friend and correspondent of Lyell.
2
James Cook’s chart of Tahiti is reproduced in Skelton 1955, Chart V. CD’s copy of the account of Cook’s voyages (Hawkesworth 1773) is in the Cambridge University Library.
3
Coral reefs, pp. 152–3.
4
Gould was at the time describing the shells collected by Joseph Pitty Couthouy, who had accompanied the United States Exploring Expedition to the Pacific, 1838–42. Couthouy had criticised a lecture in which Lyell had represented Tahiti as enclosed by a continuous reef (Couthouy 1844, p. 139).
5
W. Forbes 1836.
6
On Plate III of Coral reefs the Tahiti reef is coloured pale blue, indicating a barrier reef. CD’s information was probably required by Lyell for the seventh edition of his Principles of geology (C. Lyell 1847), in which Lyell discussed alternate bands of elevation and subsidence of the Pacific ocean floor as demonstrated by the various kinds of coral reef. Tahiti is discussed on pp. 755, 757. Lyell had earlier questioned CD on this point, see Correspondence vol. 2, letters from Charles Lyell, 13 February 1837 and 6 and 8 September 1838, and letters to Charles Lyell, [14] September [1838] and [19 February 1840].
7
Joseph Dalton Hooker had been invited to stay at Down House for a period starting from 16 January 1847 (Correspondence vol. 3, letter to J. D. Hooker, [December 1846 – January 1847]). CD’s reference is to J. D. Hooker 1848a.
8
Bunbury 1846a, 1846b, 1847. Charles James Fox Bunbury was Mary Lyell’s brother-in-law.

Manuscript Alterations and Comments

1.1 “flat”] ‘f’ over ‘d’
1.3 refer] before del carat
1.3 & have described 1.4] interl
2.2 outside)] ‘)’ over comma
2.2 30] before omitted point
3.2 submerged] after del interl ‘encircling’
3.3 encircling part of the island] interl

Please cite as “DCP-LETT-1056,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-1056