WCP3969

[1]

Old Orchard

Broadstone

Wimborne

July 6th. 1909

Prof.[essor] W.J. Sollas

Dear Sir

Many thanks for sending me your very interesting "Address" as President of the Geolog[ica]l Society, which I have just finished reading with much pleasure & profit. It is satisfactory to me to find that the quite distinct method of reasoning Geol[ological] time which you have used, leads to a result concordant with that I reached nearly 30 years ago in my Chapter on "The Earth’s Life" in my "Island Life". I there obtained [2] 28 million years as the prob[able] age of the sedimentary rocks, and I adduced reasons to show that such a period was (or might be) quite sufficient for the development of the organic world. It still seems to me that those reasons hold good.

At p.CXIII of your "Address" you say — "the deposition of sediment must have commenced with the birth of the ocean". But, surely, not necessarily at the same rate. If, as I think seems probable, there has been an almost continuous continental growth, and that in the earliest times what are now continents were archipelagos, [3] there would necessarily ^have been less denudation & more equable climates all over the globe: — & thus there would be no discrepancy between your estimate and mine.

The first part of your "Address" on the internal tides of the earth hasve also interested me greatly. The demonstration that such periodical deformation exists, & that the interior of much of the globe is practically solid, suggest another point, which you have referred to, — that the continental strains & friction in the crust, must be a continuous source of heat, I remember a [4] calculation of Sir G. Darwin, (I forget where) that if there were such tidal deformation, it would supply ^produce ample internal heat to supply all the waste by radiation, volcanoes, hot springs &c & thus preserve that uniform temperature which the geolog[ica]l record indicates & the evolution of life demands.

Yours very truly| Alfred R. Wallace [signature]