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Darwin Correspondence Project

To J. S. Henslow1   24 July – 7 November 1834


July 24th.—1834

My dear Henslow

A box has just arrived, in which are two of your most kind & affectionate letters; you do not know how happy they have made me.— One is dated Dec 12th. 1833 the other Jan: 15th of the same year!—2 By what fatality it did not arrive sooner, I cannot conjecture: I regret it much; for it contains the information, I most wanted about manner of packing &c &c: roots, with specimens of plants &c &c: This I suppose was written after the reception of my first cargo of specimens.— Not having heard from you untill March of this year; I really began to think my collections were so poor, that you were puzzled what to say: the case is now quite on the opposite tack; for you are guilty of exciting all my vain feelings to a most comfortable pitch; if hard work will atone for these thoughts I vow it shall not be spared.—

It is rather late, but I will allude to some remarks in the Jan: letter: you advise me to send home duplicates of my notes; I have been aware of the advantage of doing so; but then at sea to this day, I am invariably sick, excepting on the finest days; at which times with pelagic animals around me, I could never bring myself to the task; on shore, the most prudent person, could hardly expect such a sacrifice of time.—

My notes are becoming bulky; I have about 600 small quarto pages full; about half of this is Geology, the other imperfect descriptions of animals: with the latter I make it a rule only to describe those parts, or facts, which cannot be seen, in specimens in spirits. I keep my private Journal distinct from the above.—3 (N B this letter is a most untidy one, but my mind is untidy with joy; it is your fault, so you must take the consequence). With respect to the land Planariæ:4 unquestionably they are not Molluscous animals: I read your letters last night, this morning I took a little walk; by a curious coincidence I found a new white species of Planaria & a (new to me) Vaginulus (3d species which I have found in S. America) of Cuv: I suppose this is the animal Leonard Jenyns alludes to.— The true Onchidium of Cuv:5 I likewise know.— Amongst the marine Mollusques I have seen a good many genera & at Rio found one quite new one.— With respect to the December letter, I am very glad to hear, the four casks arrived safe; since which time you will have received another cargo, with the bird skins, about which you did not understand me.— Have any of the B. Ayrean seeds produced plants?—

From the Falklands, I acknowledged a box & letter from you; with the letter were a few seeds from Patagonia.— At present, I have specimens enough to make a heavy cargo, but shall wait as much longer as possible, because opportunities are not now so good as before.— I have just got scent of some fossil bones of a Mammoth!, what they may be, I do not know, but if gold or galloping will get them, they shall be mine. You tell me, you like hearing how I am going on & what doing; & you well may imagine how much I enjoy speaking to anyone upon sub-jects, which I am always thinking about, but never have any one to talk to with.—

After leaving the Falklands, we proceeded to the R. S. Cruz; followed up the river till within 20 miles of the Cordilleras: Unfortunately want of pro- visions compelled us to return. This expedition was most important to me, as it was a transverse section of the great Patagonian formation.— I conjecture (an accurate examination of fossils may possibly determine the point) that the main bed is somewhere about the Meiocene period, (using Mr Lyell’s expression)6 I judge from what I have seen of the present shells of Patagonia.— This bed contains an enormous field of Lava.— This is of some interest, as being a rude approximation to the age of the Volcanic part of the great range of the Andes.— Long before this it existed as a Slate & Porphyritic line of hills.— I have collected tolerable quantity of information respecting the period, (even numbers) & forms of elevations of these plains. I think these will be interesting to Mr Lyell.— I had deferred reading his third volume till my return, you may guess how much pleasure it gave me; some of his wood-cuts came so exactly into play, that I have only to refer to them, instead of redrawing similar ones.— I had my Barometer with me; I only wish I had used it more in these plains.—

The valley of S. Cruz appears to me a very curious one, at first it quite baffled me.— I believe I can show good reasons for supposing it to have been once a Northern Stts. like that of Magellan.— When I return to England, you will have some hard work in winnowing my Geology; what little I know, I have learnt in such a curious fashion, that I often feel very doubtful about the number of grains: Whatever number, they may turn out, I have enjoyed extreme pleasure in collecting them.—

In T. del Fuego I collected & examined some Corallines: I have observed one fact which quite startled me.— it is, that in the genus Sertularia, (taken in its most restricted form as by Lamouroux)7 & in 2 species which, excluding comparative expressions, I should find much difficulty in describing as different—the Polypi quite & essentially differed, in all their most important & evident parts of structure.— I have already seen enough to be convinced that the present families of Corallines, as arranged by Lamarck, Cuvier &c are highly artificial.— It appears they are in the same state, which shells were when Linnæus left them for Cuvier to rearrange.—

I do so wish I was a better hand at dissecting: I find I can do very little in the minute parts of structure; I am forced to take a very rough examination as a type for different classes of structure.—

It is most extraordinary I can no where see in my books one single description of the polypus of any one Corall (excepting Lobularia alcyonium of Savigny)8 I found a curious little stony Cellaria (a new genus) each cell provided with long toothed bristles, these are capable of various & rapid motions,—this motion is often simultaneous & can be produced by irritation.— this fact, as far as I see, is quite isolated in the history (excepting by the Flustra with organ like Vultures Head) of Zoophites.— it points out a much more intimate relation between the Polypi, than Lamarck is willing to allow.— I forget, whether I mentioned, having seen something of the manner of propagation, in that most ambiguous family, the Corallinas: I feel pretty well convinced if they are not Plants, they are not Zoophites:9 the “gemmule” of a Halimeda contained several articulations united, & ready to burst their envelope & become attached to some basis.— I believe in Zoophites, universally the gemmule produces a single Polypus, which afterwards or at the same time grows with its cell or single articulation.— The Beagle left the Sts of Magellan in the middle of winter; she found her road out by a wild unfrequented channel; well might Sir J. Narborough call the West coast South Desolation “because it is so desolate a land to behold”.—10 We were driven into Chiloe, by some very bad weather.— an Englishman gave me 3 specimens of that very fine Lucanoidal insect, which is described Camb: Phil. Trans: 2 males & one female.—11 I find Chiloe is composed of Lava & recent deposits.— the Lavas are curious from abounding or rather being in parts composed of Pitchstone.— If we go to Chiloe in the summer I shall reap an Entomological harvest.— I suppose the Botany both there & in Chili is well known.—

I forgot to state, that in the four cargoes of specimens there have been sent 3 square boxes, each containing four glass bottles.— I mention this in case they should be stowed beneath geological specimens, & thus escape your notice perhaps some spirit may be wanted in them.— If a box arrives from B. Ayres, with Megatherium head & other unnumbered specimens: be kind enough to tell me; I have strong fears for its safety.—

We arrived here the day before yesterday; the views of the distant mountains are most sublime & the climate delightful; after our long cruize in the damp gloomy climates of the South, to breathe a clear, dry air, & feel honest warm sunshine, & eat good fresh roast beef must be the summum bonum of human life.— I do not like the looks of the rocks, half so much as the beef, there is too much of those rather insipid ingredients Mica, quartz & Feldspar.— Our plans are at present undecided.— there is a good deal of work to the South of Valparaiso & to the North an indefinite quantity.— I look forward to every part with interest. I have sent you in this letter a sad dose of egotism.—but recollect I look up to you as my father in Natural History, & a son may talk about himself, to his father.— In your paternal capacity, as pro-proctor what a great deal of trouble you appear to have had.— How turbulent Cambridge is become— Before this time it will have regained its tranquillity— I have a most school-boy like wish to be there, enjoying my Holidays.— It is a most comfortable reflection to me, that a ship being made of wood & iron, cannot last for ever & therefore this voyage must have an end.—

October 28th.— This letter has been lying in my port-folio ever since July: I did not send it away, because I did not think it worth the postage: it shall now go with a box of specimens: shortly after arriving here, I set out on a geological excursion, & had a very pleasant ramble about the base of the Andes.— The whole country appears composed of breccias, (& I imagine Slates) which universally have been modified, & oftentimes completely altered by the action of fire; the varieties of porphyry thus produced is endless, but no where have I yet met with rocks which have flowed in a stream; dykes of greenstone are very numerous: Modern Volcanic action is entirely shut up in the very central parts (which cannot now be reached on account of the snow) of the Cordilleras.— To the South of the R. Maypo I examined the Tertiary plains already partially described by M. Gay.12 The fossil shells, appear to me, to be far more different from the recent ones, than in the great Patagonian formation; it will be curious if an Eocene & Meiocene (Recent there is abundance of) could be proved to exist in S. America as well as in Europe.— I have been much interested by finding abundance of recent shells at an elevation of 1300 feet; the country in many places is scattered over with shells, but these are all littoral ones. So that I suppose the 1300 feet elevation must be owing to a succession of small elevations such as in 1822. With these certain proofs of the recent residence of the ocean over all the lower parts of Chili; the outline of every view & the form of each valley possesses a high interest. Has the action of running water or the sea formed this deep ravine? Was a question which often arose in my mind, & generally was answered by finding a bed of recent shells at the bottom.— I have not sufficient arguments, but I do not believe that more than a small fraction of the height of the Andes has been formed within the Tertiary period.—

The conclusion of my excursion was very unfortunate, I became unwell & could hardly reach this place, I have been in bed for the last month, but am now rapidly getting well. I had hoped during this time to have made a good collection of insects &c but it has been impossible. I regret the less, because Chili fairly swarms with Collectors; there are more Naturalists in the country, than Carpenters or Shoemaker or any other honest trade.—

In my letter from the Falkland Isd. I said I had fears about a box with a Megatherium. I have since heard from B. Ayres, that it went to Liverpool by the Brig Basingwaithe.— If you have not received it—it is, I think, worth taking some trouble about. In October two casks & a jar were sent by H.M.S. Samarang viâ Portsmouth I have no doubt you have received them. With this letter, I send a good many bird skins; in the same box with them, there is a paper parcel, containing pill boxes with insects: the other pill-boxes require no particular care: You will see in two of these boxes, some dried terrestrial Planariæ, the only method I have found of preserving them (they are exceedingly brittle) By examining the white species I understand some little of the internal structure.— There are two small parcels of seeds.— There are some plants, which I hope may interest you, or at least those from Patagonia, where I collected every one in flower:— There is a bottle, clumsily, but I think securely corked, containing water & gaz from the hot Baths of Cauquenes, seated at foot of Andes & long celebrated for medicinal properties.— I took pains in filling & securing both water & gaz.— If you can find any one who likes to analyze them; I should think it would be worth the trouble.— I have not time at present to copy my few observations about the locality &c &c of these Springs.— Will you tell me, how the Arachnidæ, which I have sent home, for instance those from Rio appear to be preserved.— I have doubts whether it is worth while collecting them.—

We sail the day after tomorrow: our plans are at last limited & definite: I am delighted to say we have bid an eternal adieu to T. del Fuego.— The Beagle will not proceed further South than C. Tres Montes. From which point we survey to the North. The Chonos archipelago is delightfully unknown; fine deep inlets running into the Cordilleras, where we can steer by the light of a Volcano.— I do not know, which part of the voyage, now offers the most attractions.— This is a shamefully untidy letter, but you must forgive me & believe me | My dear Henslow | Yours most truly obliged | Charles Darwin

Novb. 7th.—


The following passages from this letter were extracted by Henslow and published in the Cambridge Philosophical Society pamphlet: 5.1 ‘After leaving … similar ones.’ 5.15; 5.8 CD’s ‘field’ changed back to CD’s del ‘mass’; 5.11 ‘period’ changed to ‘various periods’ and ‘(even numbers)’ omitted by JSH 6.1 ‘The valley … Magellan.’ 6.3 7.1 ‘In T. del Fuego … rearrange.’ 7.9; 7.8 ‘to me, that’ inserted after ‘appears’ by JSH 9.1 ‘It is most extraordinary … Pitchstone.’ 9.22; 9.17 ‘Narborough’ incorrectly transcribed ‘Nasborough’; 9.22 ‘in parts’ omitted 11.1 ‘We arrived … Feldspar.’ 11.6 12.3 ‘shortly after … Tertiary period.—’ 12.25; 12.12 ‘far more different’ changed to ‘differ more widely’; 12.13 ‘formation’ inserted after ‘Meiocene’; 12.22 ‘deep’ omitted
The December letter has not been found.
On the records CD kept during the voyage see Correspondence vol.1, Appendix II.
Henslow marked this passage, 3.6 ‘With respect … Cuv: ’ 3.11, for communication to the Cambridge Philosophical Society, but it was not reprinted in the pamphlet, possibly because he still felt CD to be mistaken about the land Planaria. CD described them in Journal of researches, pp. 30–1, and in more detail in a paper of 1844 (see Collected papers 1: 182–93).
Lyell first used the term ‘Miocene’ in volume three of Principles of geology, p. 54.
Jean Vincent Félix Lamouroux. CD had with him Lamouroux 1821, a lightly annotated copy of which is in Darwin Library–CUL, inscribed ‘C. Darwin’.
Marie-Jules-César Lelorgne de Savigny.
The nature of Corallines, now defined as plants, was a matter of debate in this period. For a discussion of this question and of CD’s thinking on the subject, see Sloan 1985.
Sir John Narbrough (also spelled Narborough) visited the Straits of Magellan and the west coast of South America (Narbrough 1694). Since the Beagle’s survey covered much of Narbrough’s route, Robert FitzRoy probably had a copy in the ship’s library, but this is the only mention of the work. A version was reprinted in volume three (1813) of Burney 1803–17.
Stephens 1833. CD may have received a copy of the paper from Henslow. It was read 16 May 1831 and described a new genus of beetle, Chiasognathus, which was sent to the Cambridge Philosophical Society by Dr Grant the surgeon of H.M.S. Forte. It too had been found on the island of Chiloé.
Gay 1833. A lightly annotated copy is in ‘Philosophical tracts’, Darwin Library–CUL (see letter to Robert FitzRoy, [28 August 1834]).


Burney, James. 1803–17. A chronological history of the discoveries in the South Sea or Pacific Ocean. 5 vols. London.

Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

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

Gay, Claude. 1833. Aperçu sur les recherches d’histoire naturelle faites dans l’Amérique du Sud, et principalement dans le Chili, pendant les années 1830 et 1831. Annales des Sciences Naturelles 28: 369–93.

Lamouroux, Jean Vincent Félix. 1821. Exposition méthodique des genres de l’ordre des Polypiers. Paris.

Narbrough, John. 1694. An account of several late voyages and discoveries to the south and north towards the Streights of Magellan, the South Seas, … also towards Nova Zembla, Greenland or Spitsberg. 2 pts. London.

Sloan, Phillip R. 1985. Darwin’s invertebrate program, 1826-1836: preconditions for transformism.The Darwinian heritage, edited by David Kohn. Princeton: Princeton University Press in association with Nova Pacifica (Wellington, NZ). [Vols. 4,7,9]

Stephens, James Francis. 1833. Description of Chiasognathus grantii, a new lucanideous insect forming the type of an undescribed genus, together with some brief remarks upon its structure and affinities. [Read 16 May 1831.] Transactions of the Cambridge Philosophical Society 4: 209__17.


CD is excited by JSH’s high opinion of his collections.

Discusses his notes and some new discoveries. Summary of events since leaving Falklands.

Geology of Patagonia.

Corallines at Tierra del Fuego convince him of artificiality of arrangement of their families by Lamarck and Cuvier.

Geological expedition in Andes, ending with serious illness. Specimens being sent.

Letter details

Letter no.
Charles Robert Darwin
John Stevens Henslow
Sent from
Source of text
Royal Botanic Gardens, Kew (Henslow letters: 22 DAR/1/1/22)
Physical description
ALS 10pp †

Please cite as

Darwin Correspondence Project, “Letter no. 251,” accessed on 18 July 2024,

Also published in The Correspondence of Charles Darwin, vol. 1