My dear Henslow

Upon our arrival at this place I was delighted at receiving your letter dated Aug. 31.— Nothing for a long time has given me so much pleasure. Independent of this pleasure, your account of the safe arrival of my second cargo & that some of the Specimens were interesting, has been, as you may well suppose, most highly satisfactory to me.—

I am quite astonished that such miserable fragments of the Megatherium should have been worth all the trouble M^r Clift has bestowed on them. I have been alarmed by the expression cleaning all the bones, as I am afraid the printed numbers will be lost: the reason I am so anxious they should not be, is that a part were found in a gravel with recent shells, but others in a very different bed.— Now with these latter there were bones of an Agouti, a genus of animals I believe now peculiar to America & it would be curious to prove some one of the same genus coexisted with the Megatherium; such & many other points entirely depend on the numbers being carefully preserved.— My entire ignorance of comparative Anatomy makes me quite dependent on the numbers: so that you will see my geological notes will be useless without I am certain to what specimens I refer.— Since receiving these specimens, you ought to have received two others cargos, shipped from the Plata in July & November 1833.— With the latter there was a heavy box of fossil remains, which is now I suppose at Plymouth. I followed this plan from not liking to give you so much trouble: it contains another imperfect Megatherium head, & some part of the skeleton of an animal, of which I formerly sent the jaw, which had four teeth on each side in shape like this .— I am curious to know to what it belongs.—²

Shortly before I left M: Video I bought far up in the country for two shillings a head of a Megatherium which must have been when found quite perfect.— The Gauchos however broke the teeth & lost the lower jaw, but the lower & internal parts are tolerably perfect: It is now, I hope, on the high seas in pursuit of me.— It is a most flattering encouragement to find Men, like M^r Clift, who will take such interest, in what I send home.—

I am very glad the plants give you any pleasure; I do assure you I was so ashamed of them, I had a great mind to throw them away; but if they give you any pleasure I am indeed bound, & will pledge myself to collect whenever we are in parts not often visited by Ships & Collectors.— I collected all the plants, which were in flower on the coast of Patagonia at Port Desire & St. Julian; also on the Eastern parts of Tierra del Fuego, where the climate & features of T del Fuego & Patagonia are united. With them there are as many seeds, as I could find (you had better plant all y^e rubbish which I send, for some of the seeds were very small).— The soil of Patagonia is very dry, gravelly & light.— in East Tierra, it is gravelly—peaty & damp.— Since leaving the R. Plata, I have had some opportunities of examining the great Southern Patagonian formation.— I have a good many shells; from the little I know of the subject it must be a Tertiary formation for some of the shells & (Corallines?) now exist in the sea.— others I believe do not.— This bed, which is chiefly characterised by a great Oyster is covered by a very curious bed of Porphyry pebbles, which I have traced for more than 700 miles.—but the most curious fact is that the whole of the East coast of South part of S. America has been elevated from the ocean, since a period during which Muscles have not lost their blue color.— At Port St Julian I found some very perfect bones of some large animal, I fancy a Mastodon.—³ the bones of one hind extremity are very perfect & solid.— This is interesting as the Latitude is between 49^o & 50^o & the site is so far removed from the great Pampas, where bones of the narrow toothed Mastodon are so frequently found— By the way this Mastodon & the Megatherium, I have no doubt were fellow brethren in the ancient plains Relics of the Megatherium I have found at a distance of nearly 600 miles apart in a N & S. line.—

In Tierra del Fuego I have been interested in finding some sort of Ammonite (also I believe found by Capt King) in the Slate near Port Famine; on the Eastern coast there are some curious alluvial plains, by which the existence of certain quadrupeds in the islands can clearly be accounted for.— There is a sandstone, with the impression of the leaves of the common Beech tree also modern shells, &c &c.— On the surface of which table land there are, as usual, muscles with their blue color &c.— This is the report of my geological section! to you my President & Master.— I am quite charmed with Geology but like the wise animal between two bundles of hay, I do not know which to like the best, the old crystalline group of rocks or the softer & fossiliferous beds.— When puzzling about stratification &c, I feel inclined to cry a fig for your big oysters & your bigger Megatheriums.— But then when digging out some fine bones, I wonder how any man can tire his arms with hammering granite.— By the way I have not one clear idea about cleavage, stratification, lines of upheaval.— I have no books, which tell me much & what they do I cannot apply to what I see. In consequence I draw my own conclusions, & most gloriously ridiculous ones they are, I sometimes fancy I shall persuade myself there are no such things as mountains, which would be a very original discovery to make in Tierra del Fuego.— Can you throw any light into my mind, by telling me what relation cleavage & planes of deposition bear to each other?—

And now for my second section Zoology.— I have chiefly been employed in preparing myself for the South sea, by examining the Polypi of the smaller Corallines in these latitudes.— Many in themselves are very curious, & I think are quite undescribed, there was one appalling one, allied to a Flustra which I daresay I mentioned having found to the Northward, where the cells have a moveable organ (like a Vultures head, with a dilatable beak), fixed on the edge. But what is of more general interest is the unquestionable (as it appears to me) existence of another species of ostrich, besides the Struthio Rhea.— All the Gauchos & Indians state it is the case: & I place the greatest faith in their observations.— I have head, neck, piece of skin, feathers, & legs of one. The differences are chiefly in color of feathers & scales on legs, being feathered below the knees; nidification & geographical distribution.—⁴

So much for what I have lately done; the prospect before me is full of sunshine: fine weather, glorious scenery, the geology of the Andes; plains abounding with organic remains, (which perhaps I may have the good luck to catch in the very act of moving); and lastly an ocean & its shores abounding with life.— So that, if nothing unforeseen happens I will stick to the voyage; although, for what I can see, this may last till we return a fine set of whiteheaded old gentlemen.—

I have to thank you most cordially for sending me the Books.—⁵ I am now reading the Oxford Report.—⁶ the whole account of your proceedings is most glorious; you, remaining in England, cannot well imagine how excessively interesting I find the reports; I am sure, from my own thrilling sensations, when reading them, that they cannot fail to have an excellent effect upon all those residing in distant colonies, & who have little opportunity of seeing the Periodicals.— My hammer has flown with redoubled force on the devoted blocks; as I thought over the eloquence of the Cambridge President⁷ I hit harder & harder blows. I hope, to give my arm strength for the Cordilleras, you will send me, through Capt. Beaufort, a copy of the Cambridge Report.—⁸

I have forgotten to mention, that for some time past & for the future I will put a pencil cross on the pill-boxes containing insects; as these alone will require being kept particularly dry, it may perhaps save you some trouble.—

When this letter will go, I do not know, as this little seat of discord has lately been embroiled by a dreadful scene of murder & at present there are more prisoners, than inhabitants.—⁹ If a merchant vessel is chartered to take them to Rio I will send some specimens (especially my few plants & seeds).—

Remember me to all my Cambridge friends.— I love & treasure up every recollection of dear old Cambridge.—

I am much obliged to you for putting my name down to poor Rams⁠⟨⁠ay’s⁠⟩⁠ Monument— I never think of him, without the warmest admiration.— Farewell my dear Henslow—believe my your most obliged & affectionate friend. Charles Darwin.—

N.B. What I have said about the numbers attached to the fossils, applies to every part of my collections.— Videlicet. Colors of all the Fish: habits of birds &c &c

There is no opportunity of sending a Cargo: I only send this, with the seeds, some of which I hope may grow, & show the nature of the plants far better than my Herbarium. They go through Capt. Beaufort: Give M^r Whewell my best thanks for sending me his tide paper:¹⁰ all on board are much interested by it.— Remember me most kindly to M^rs. Henslow & Leonard Jenyns.—

The Box of fossil remains, to which I have alluded is with D^r. Armstrong at Plymouth: if you think it worth while, you can write to him (just stating the reasons) & he will (perhaps be too glad) to forward it. Capt. FitzRoy will mention in a letter the possibility of your writing for the Box.— It could be easily sent by water to London & from thence either by land or water to Cambridge.— | Once more dear Henslow, Farewell.—