To J. S. Henslow1  – 13 March 1835
My dear Henslow
We now are lying becalmed off Valparaiso & I will take the opportunity of writing a few lines to you. The termination of our voyage is at last decided on—we leave the coast of America in the beginning of September & hope to reach England in the same month of 1836. I am heartily glad of it, nothing should induce me to stay out any longer. As it is, it will be nearly as long as a seven years transportation. But now that I do clearly see England in the distance, I care for nothing, not even sea sickness. In October perhaps I shall be in Cambridge & who knows but taking a walk with you round by Shelford common.— You can hardly understand how I long to see you & all my friends again; & now there only wants a year & half to that time. We shall see a great many places in this interval, but I am afraid there will be but few opportunities for much Natural History. We are now making a passage from Concepcion.— You will have heard an account of the dreadful earthquake of the 20th of February. I wish some of the Geologists who think the Earthquakes of these times are trifling could see the way the solid rock is shivered In the town there is not one house habitable; the ruins remind me of the drawings of the desolated Eastern cities.— We were at Baldivia at the time & felt the shock very severely. The sensation is more like that of skating over very thin ice; that is distinct undulations were perceptible. The whole scene of Concepcion & Talcuana is one of the most interesting spectacles we have beheld since leaving England.—
Since leaving Valparaiso, during this cruize, I have done little excepting in Geology.— In the modern Tertiary strata I have examined 4 bands of disturbance, which reminded me on a small scale of the famous tract in the Isle of Wight.—2 In one spot there were beautiful examples of 3 different forms of upheaval.— In two cases I think I can show, that the inclination is owing to the presence of a system of parallel dykes traversing the inferior Mica Slate. The whole of the coast from Chiloe to S. extreme of the Pen: of Tres Montes is composed of the latter rock; it is traversed by very numerous dykes, the mineralogical nature of which will I suspect turn out very curious. I examined one grand transverse chain of Granite, which has clearly burst up through the overlying Slate. At P. Tres Montes there has been an old Volcanic focus, which corresponds to another in the North part of Chiloe. I was much pleased at Chiloe by finding a thick bed of recent oysters shells, &c, capping the Tertiary plain, out of which grew large forest trees.— I can now prove that both sides of the Andes have risen in the recent period to a considerable height.— Here the shells were 350 ft above the sea.—
In Zoology I have done but very little; excepting a large collection of minute Diptera & Hymenoptera from Chiloe. I took in one day, Pselaphus, Anaspis, Latridius Leiodes, Cercyon, & Elmis & two beautiful true Carabi, I might almost have fancied myself collecting in England. A new & pretty genus of Nudibranch Mollusc: which cannot crawl on a flat surface: & a genus in the family of Balanidæ, which has not a true case, but lives in minute cavities in the shells of the Concholepas,3 are nearly the only two novelties. You were surprised at hearing of land Planariæ; you will equally be so, when you see leaches, which live entirely out of water in the fore〈sts〉 of Chiloe & Valdivia.— Before the Beagle sails for Lima, I shall be obliged to send away one more box: this will be the last; with which I shall trouble you. I am afraid so many boxes must have been very much in your way. I trust they may turn out worth their stowage. I will write again, when this last Cargo is sent. You ought to have received about a month since 2 boxes by H.M.S. Challenger & before that 2 Casks & one jar by H.M.S. Samarang.— Will you write to me directed to Sydney, not long after receiving this letter.— I am very unreasonable in begging for so many letters; but bear with me for one year more.— If any come directed in the mean time to S. America, they will be forwarded to Sydney by the Admiral.—
Valparaiso March 13th.— I am on the point of starting to endeavour to pass the Cordilleras, but am very doubtful of the issue. Three month’s letters are somewhere mislaid: but I hope they will be found.— Perhaps there may be a letter from you.— I am anxious to know whether the bird skins from the River Plate in a tinned box came safe.— I think that collection will be good, as I took much pains with them.— I am in a great hurry, so excuse this stupid shabby little letter. Oh the goodly month of September 1836.— To think that I shall again be actually living quietly in Cambridge.— It is too good a prospect, it will spoil the Cordilleras.
So my dear Henslow, good night | Your Most obliged & affectionate friend | Chas. Darwin.
The termination of the voyage has been decided – September 1836.
The earthquake of Concepción.
His geological observations (since November). Can now prove both sides of the Andes have recently risen to considerable heights.
Plans to cross the Cordilleras.