The geology of these mountains pleased me in one respect; when reading Lyell, it had always struck me that if the crust of the world goes on changing in a circle, there ought to be somewhere found formations which, having the age of the great European Secondary beds, should possess the structure of Tertiary rocks or those formed amidst islands and in limited basins. Now the alternations of lava and coarse sediment which form the upper parts of the Andes, correspond exactly to what would accumulate under such circumstances. In consequence of this, I can only very roughly separate into three divisions the varying strata (perhaps 8,000 feet thick) which compose these mountains. I am afraid you will tell me to learn my ABC to know quartz from feldspar before I indulge in such speculations. I lately got hold of a report on M. Dessalines D'Orbigny's labours in S. America (7/2. "Voyage dans l'Amerique Meridionale, etc." (A. Dessalines D'Orbigny).); I experienced rather a debasing degree of vexation to find he has described the Geology of the Pampas, and that I have had some hard riding for nothing, it was however gratifying that my conclusions are the same, as far as I can collect, with his results. It is also capital that the whole of Bolivia will be described. I hope to be able to connect his geology of that country with mine of Chili. After leaving Copiapo, we touched at Iquique. I visited but do not quite understand the position of the nitrate of soda beds. Here in Peru, from the state of anarchy, I can make no expedition.
I hear from home, that my brother is going to send me a box with books, and a letter from you. It is very unfortunate that I cannot receive this before we reach Sydney, even if it ever gets safely so far. I shall not have another opportunity for many months of again writing to you. Will you have the charity to send me one more letter (as soon as this reaches you) directed to the C. of Good Hope. Your letters besides affording me the greatest delight always give me a fresh stimulus for exertion. Excuse this geological prosy letter, and farewell till you hear from me at Sydney, and see me in the autumn of 1836.
LETTER 8. TO JOSIAH WEDGWOOD. [Shrewsbury, October 5th, 1836.]
My dear Uncle
The "Beagle" arrived at Falmouth on Sunday evening, and I reached home late last night. My head is quite confused with so much delight, but I cannot allow my sisters to tell you first how happy I am to see all my dear friends again. I am obliged to return in three or four days to London, where the "Beagle" will be paid off, and then I shall pay Shrewsbury a longer visit. I am most anxious once again to see Maer, and all its inhabitants, so that in the course of two or three weeks, I hope in person to thank you, as being my first Lord of the Admiralty. (8/1. Readers of the "Life and Letters" will remember that it was to Josiah Wedgwood that Darwin owed the great opportunity of his life ("Life and Letters," Volume I., page 59), and it was fitting that he should report himself to his "first Lord of the Admiralty." The present letter clears up a small obscurity to which Mr. Poulton has called attention ("Charles Darwin and the Theory of Natural Selection," "Century" Series, 1896, page 25). Writing to Fitz-Roy from Shrewsbury on October 6th, Darwin says, "I arrived here yesterday morning at breakfast time." This refers to his arrival at his father's house, after having slept at the inn. The date of his arrival in Shrewsbury was, therefore, October 4th, as given in the "Life and Letters," I., page 272.) The entries in his Diary are:-- October 2, 1831. Took leave of my home. October 4, 1836. Reached Shrewsbury after absence of 5 years and 2 days.) I am so very happy I hardly know what I am writing. Believe me your most affectionate nephew,
CHAS. DARWIN.
LETTER 9. TO C. LYELL. Shrewsbury, Monday [November 12th, 1838].
My dear Lyell
I suppose you will be in Hart St. (9/1. Sir Charles Lyell lived at 16, Hart Street, Bloomsbury.) to-morrow [or] the 14th.