1809-1842] VOYAGE 15 



it is your fault, so you must take the consequences.) With Letter 5 

 respect to the land Planarice, 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, and a new to me 

 Vaginulus (third species which I have found in S. America) 

 of Cuvier. Amongst the marine mollusques I have seen 

 a good many genera, and 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 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 and 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 and what doing, and you 

 well may imagine how much I enjoy speaking to anyone 

 upon subjects which I am always thinking about, but never 

 have any one to talk to [about]. After leaving the Falklands 

 we proceeded to the Rio S. Cruz, following up the river till 

 within twenty miles of the Cordilleras. Unfortunately want of 

 provisions 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 Miocene period (using Mr. 

 Lyell's expression) ; 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 

 and porphyritic line of hills. I have collected a tolerable 

 quantity of information respecting the period and 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 



