1832.] GEOLOGY. 235 



C. Darwin to J. S. Henslow. 



Rio de Janeiro, May 18, 1832. 



MY DEAR HENSLOW, 



***** 



Till arriving at Teneriffe (we did not touch at Ma- 

 deira) I was scarcely out of my hammock, and really suf- 

 fered more than you can well imagine from such a cause. At 

 Santa Cruz, whilst looking amongst the clouds for the Peak, 

 and repeating to myself Humboldt's sublime descriptions, it 

 was announced we must perform twelve days' strict quaran- 

 tine. We had made a short passage, so " Up jib," and away 

 for St. Jago. You will say all this sounds very bad, and so it 

 was ; but from that to the present time it has been nearly one 

 scene of continual enjoyment. A net over the stern kept me 

 at full work till we arrived at St. Jago. Here we spent three 

 most delightful weeks. The geology was pre-eminently inte- 

 resting, and I believe quite new ; there are some facts on a 

 large scale of upraised coast (which is an excellent epoch for 

 all the volcanic rocks to date from), that would interest 

 Mr. Lyell. 



One great source of perplexity to me is an utter ignorance 

 whether I note the right facts, and whether they are of suffi- 

 cient importance to interest others. In the one thing collect- 

 ing I cannot go wrong. St. Jago is singularly barren, and 

 produces few plants or insects, so that my hammer was my 

 usual companion, and in its company most delightful hours I 

 spent. On the coast I collected many marine animals, chiefly 

 gasteropodous (I think some new). I examined pretty accu- 

 rately a Caryophyllia, and, if my eyes are not bewitched, 

 former descriptions have not the slightest resemblance to the 

 animal. I took several specimens of an Octopus which pos- 

 sessed a most marvellous power of changing its colours, equal- 

 ling any chameleon, and evidently accommodating the 

 changes to the colour of the ground which it passed over. 



