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Darwin Correspondence Project

From Edward Forbes   [7 August 1846]1


Dear Darwin

The shells which needed describing, are now described.2 Shall I send you the MS?

The Conception Nautilus I cannot satisfactorily identify with any other. I propose to call it N. D’Orbignyanus if you have no objection. It comes very near some lower & middle cretaceous species.3

I send the Mss. wanted.

I leave the Fuego Ancyloceras unnamed. Give D’Orbigny’s supposed identifn. of it. It is however not in a state sufficiently secure for my conscience to hang upon its horn.4

The Terra del fuego fragments impress me with the notion that they indicate cretaceous epoch—probably the early part.

Such also is the impression I take up (& more firmly) from those of Corderilla of Central Chili.5 I send that Mss. with the other. I am now ready to see Sowerby.6 If he is not coming tomorrow, I will be in my office all Monday.

Our survey reports are now out. I wish I could send you a copy of my paper7 but as yet have not been able to lay hands on one for myself

Ever, most sincerely | Edward Forbes

CD annotations

crossed pencil
2.3 lower & middle cretaceous] underl pencil
crossed pencil


The conjectured date is the first Friday after the announcement of the publication of E. Forbes 1846 in Memoirs of the Geological Survey (The Publishers’ Circular, 1 August 1846, listing the volume as ‘just published’ in the period 13–29 July).
Forbes described CD’s Secondary fossil shells in the appendix of South America.
Forbes eventually decided it resembled two species from the Upper Greensand (South America, pp. 127, 265).
According to South America, p. 152, Forbes agreed with Orbigny that the fossil was early Cretaceous.
Noted by CD in South America, p. 193.
George Brettingham Sowerby Jr, who illustrated the fossil shells for the plates in South America. Forbes and George Brettingham Sowerby prepared descriptions for the appendix.


Forbes, Edward. 1846. On the connexion between the distribution of the existing fauna and flora of the British Isles, and the geological changes which have affected their area, especially during the epoch of the Northern Drift. Memoirs of the Geological Survey of Great Britain, and of the Museum of Economic Geology in London 1: 336–432.

South America: Geological observations on South America. Being the third 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. 1846.


Has completed descriptions of S. American fossil shells [for South America]. Proposes to name a Nautilus after A. D. d’Orbigny.

Letter details

Letter no.
Edward Forbes
Charles Robert Darwin
Sent from
Source of text
DAR 43.1: 49
Physical description
2pp †

Please cite as

Darwin Correspondence Project, “Letter no. 989,” accessed on 23 February 2020,

Also published in The Correspondence of Charles Darwin, vol. 3