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CHAP. XXIX.
I have been observing tbe land and fresbwater shellswith some attention. After collecting some thirtj species,I have never seen that large and conspicuous English sbell,Helix aspersa. As it is not fossil in tbe loess of the Ehine, Isuppose Woodward may be right in saying ‘that it came in•with man and the dog.’ Helix arbnstorum swarms above all;H. nemoralis (or hortensis) not very common. On the whole,perhaps six in twenty-five not British. I am glad youalluded to A. De Candolle’s book, which he sent me, andwhich I have always been meaning, and still mean to read.Hooker’s donbts as to the Pinus pumilis being the Scotch firinterested me much, for though the possibility struck me, Igave up the idea when I saw how positivelv it ranks as atrne species in the books. Its cones seemed to me as largeas those of a tall Scotch fir, which has the effect of makingit look peculiar, and more unlike than its mere dwarfishnesswould do. It never gets so low as the (Spruce?) on theWhite Mountains, but I saw the Persicaria striving to top it,as did Lycopodium dendroides presume to do in the case ofthe dwarfed American fir trees. I saw no gradual passage,but the change from a region where the snow does not lie solong, to one where it endures for a great many months, israther sudden on the Eiesengeberge.
With love to Franees, ever affectionately yours,
Chakles Lyell.
To Professor George Härtung.
My dear Hartung,—I was very glad to learn by yourletter which I found here, that we may look forward to thepleasure of seeing you in London on your way to Madeira.I have made progress, since I saw you, in German, havinghad to talk some whole days with good geologists whoknow no other language, so I hope to make out what youwrite in your own tongue, and can always get the aid of mywife when in doubt. I am well pleased that you have foundin conversing with your friends, how much (and verydeservedly) the Connection of the history of the Madeira andCanary volcanos is dependent for one of its greatest interestson the various groups of organic remains.