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Darwin Correspondence Project

From T. G. Bonney   5 February 1882

23 Denning Road, | Hampstead, N.W.

Feb 5. 1882

My dear Sir

I am greatly obliged to you for the trouble which you have taken in writing to me on the subject of the statement in Science1   Either Dr Hahn or the writer of that paragraph, is as I suspect, a person of vivid imagination and inaccurate habits— I disbelieved it when I read it from à priori reasons, but in contradicting a statement one likes to have something better than one’s own conception of the possible or impossible in another person—2

I saw a few of Dr Hahns slides but did not look at many because I saw enough to perceive it would be a waste of time, as he clearly could not distinguish between mineral and organic structures. Such as I saw were not unfamiliar to me as a microscopic petrologist and very different to those organic structures with which occasional work with foraminifera and their slices of sedimentary rocks had acquainted me.3

As regards Eozoon, though I admit the question is not without its difficulties, I think the evidence in favour of its being an organic structure is rather strong—4 The particular direction my researches have taken have made me very familiar with olivine rock serpentine, devitrified glassy rocks, and many kinds of metamorphic sedimentary rocks, and I have very rarely seen structures at all parallel.5 The structure most nearly and commonly paralleled is the ‘nummuline layer’ of the ‘proper wall’—6 I have occasionally seen structures something like—though the resemblance is but distant—to the canal system—and of course one has sometimes rocks irregularly banded with more than one mineral

Now there seem to me two strong arguements in favour of the organic origin— One. that Carpenter Dawson &c positively assert that you have the ‘canal system’ sometimes preserved by infiltration with more than one mineral (in one case with three) I have seen nothing like this in a mineral imitative structure, and it seems to me most improbable that it can occur except in an organism—7 The other: that supposing you get to some minerals or rocks—a sort of chamber like banding— in others occasionally (but seldom) something like the nummuline layer, in others (very rarely) a rude approximation to the canal system— the chance of these three structures being found, and rather persistently, in a large mass of rock is extremely small, unless, seeing they do meet in certain organisms, the specimen has had an organic origin.—

Still I think that it is more prudent to wait for further evidence before building any theories on Eozoon as a foundation—

With many thanks for your kindness in writing | I am Dear Sir | Very faithfully yours | J. G Bonney


CD’s letter has not been found, but see the letter from T. G. Bonney to W. E. Darwin, [before 2 February 1882] and n. 2, and the letter from W. E. Darwin, 2 February [1882] and n. 2.
Otto Hahn had sent CD a copy of Die Meteorite (Chondrite) und ihre Organismen (Meteorites (chondrites) and their organisms; Hahn 1880). Hahn believed he had found various organisms in a stony (chondritic) meteorite. CD had told Hahn that if his observations were verified by several judges, he would have made ‘one of the most remarkable discoveries ever recorded’ (Correspondence vol. 28, letter to Otto Hahn, 20 December 1880). The journal Science had reported that Hahn visited CD to show him microscopic slides and claimed that CD, on viewing these, exclaimed, ‘what a wonderful discovery!’ (Science, 27 August 1881, p. 410).
Foraminifera are single-celled protists with tests or shells.
In 1864, John William Dawson identified samples taken from pre-Silurian strata in eastern Canada as fossilised Foraminifera; he named the species Eozoon canadense, the ‘Dawn animal from Canada’ (Dawson 1864). Further samples were sent to William Benjamin Carpenter, an expert on Foraminifera, who confirmed Dawson’s interpretation (Carpenter 1864). CD added information on the discovery of Eozoon canadense to Origin 4th ed., p. 371, as substantiating his claim, made in Origin, p. 307, that life existed before the Silurian period. The interpretation of the samples as pre-Silurian fossils remained controversial, however (see, for example, Carpenter 1866 and King and Rowney 1866), and by the end of the century, comparisons with similar, more recent, formations indicated that the samples were mineral in origin (see O’Brien 1970 and Schopf 2000).
Olivine is a mineral series in which iron and magnesium substitute for one another in the same crystal structure. Devitrified glassy rocks are those in which spherulites (small, rounded, crystalline structures) have formed in silica-rich glassy rocks like obsidian.
The ‘nummuline layer’ referred to the Tertiary strata where Foraminifera of the genus Nummulites were found.
Carpenter had argued that the ‘canal system’ corresponded with similar canals in recent specimens of Foraminifera such as Polystomella (a synonym of Elphidium) and Calcarina (Carpenter 1864, p. 64).


Carpenter, William Benjamin. 1864a. Additional note on the structure and affinities of Eozoön Canadense. [Read 23 November 1864.] Quarterly Journal of the Geological Society of London 21 (1865): 59–66.

Carpenter, William Benjamin. 1866. Supplemental notes on the structure and affinities of Eozoon Canadense. [Read 10 January 1866.] Quarterly Journal of the Geological Society of London 22: 219–28.

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

Dawson, John William. 1864. On the structure of certain organic remains in the Laurentian limestones of Canada. [Read 23 November 1864.] Quarterly Journal of the Geological Society of London 21 (1865): 51–9.

Hahn, Otto. 1880. Die Meteorite (Chondrite) und ihre Organismen. Tübingen: H. Laupp’schen Buchhandlung.

King, William and Rowney, Thomas Henry. 1866. On the so-called ‘Eozoonal Rock’. Quarterly Journal of the Geological Society of London 22: 185–218.

O’Brien, Charles F. 1970. Eozoön Canadense: ‘the dawn animal of Canada’. Isis 61: 206–23.

Origin 4th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 4th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1866.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Schopf, J. William. 2000. Solution to Darwin’s dilemma: discovery of the missing Precambrian record of life. Proceedings of the National Academy of Sciences of the United States of America 97: 6947–53.


Thanks for writing. Had disbelieved the story. He has seen Dr Hahn’s slides and it is clear that Hahn cannot distinguish between mineral and organic structures.

Letter details

Letter no.
Thomas George Bonney
Charles Robert Darwin
Sent from
Source of text
DAR 160: 246, 248
Physical description
ALS 7pp

Please cite as

Darwin Correspondence Project, “Letter no. 13663,” accessed on 30 November 2023,