WCP2223

[1]

March 31^st 1869

73 Harley St.

Dear Wallace

I have just received a letter¹ from Sir Charles Bunbury² who is reading your book with much pleasure,³ and with a thorough appreciation, among other things, of your generalizations on geographical distributions, his forte you know is botany, and I have always been accustomed to rely on his criticisms in that [2] department as most sound, and have never found him otherwise. I will therefore lose no time, as this is my last day in Town, in sending you some ^comments which may not be too late for your cheaper edition, in case they should lead you to think that what you quote from Motley⁴ should require some modification.⁵

At page 184 nearly half of the genera given in the list are not characteristically European, but either groups of very wide distribution or such as merely struggle [3] into Europe. "Thus Impatiens has ninety-six Indian species, and one European; Lobelia, 26 in South Africa, a great many in Mexico, two or three in Europe; Oxalis, above 100 in South Africa, and one (?)⁶ strictly European; Rhododendron, 4 in Europe, and 8 or 10 species times as many in India. Even Quercus and Vaccinium according to Joseph Hooker⁷, have their headquarters not in Europe, but in subtropical Asia, again, Hypericum occurs in almost every country which is not very cold; and Polygonum is still more ubiquitous." —

M^r Motley perhaps merely [4] meant by European genera of which the European representa[tives] are most familiarly known, but when you reason on the migration of a form from the northern to the southern hemisphere or the other way, it becomes of great consequence to know on which side of the Equator is the head-quarters of the genus, as, if the Oxalis for example belongs so decidedly to the south of the Line, the European straggler had most probably to make its way northward to Europe.

I leave Town tomorrow, but letters will always follow me and I will ask Bunbury to send me additional criticisms, unless you say it is too late for a new edition.

A friend asked me yesterday [5] why are there no lakes in Fuegien [Tierra del Fuego] although the glaciers reach the sea in the Strait of Magalheans [Magellan]. To this perhaps you would answer, there may be no great lakes, but we know too little of the geography of the region to say there are no mountain tarns. Lakes are also said to be quite absent in Patagonia.

Perhaps the most difficult cases for you are some of the lakes in Massachusetts & Maine which are away from the mountains and in low ground, assuming them not to be morainic and I certainly think that many must be [6] rock-basins. I find it as difficult to imagine a peculiar thickness or weight of moving ice just on those spots often in granite.

I ha seem unluckily to have given a wrong reference to Humboldt⁸ about the Aripao forest in the Caraccas [Caracas], or I must have got a different edition of Humboldt’s work from that in the Royal & Geographical Societies’ Libraries.⁹

Do not omit to criticise some of my glacial reasoning which you did not allude to the other day—

I shall take your book with me to read with my nephew¹⁰ at inns during our [7] tour, or when we are snowed up which seems a possible event, for I am told that at Lowestoft, to which we are going among other places, there has been 18 inches of snow without drifting.

Last year I never saw pebbles more well glaciated and striated than in the drift of the cliff at Corton near Lowestoft[.]

believe me | ever most truly yours | Cha Lyell [signature]

PS. In cases like Quercus and Vaccinium where the head-quarters [8] are sub-tropical, the migration of such forms by aid of the glacial period is not required and is even improbable.