To Charles Lyell 12 July 1
Down, | Beckenham, Kent.
My dear Lyell
I have been glad to see the enclosed & returned.—2 It seems to me very cool in Agassiz to doubt the recent upheaval of Patagonia, without having visited any part; & he entirely misrepresents me in saying that I infer upheaval from the form of the land, as I trusted entirely to shells embedded & on the surface. It is simply monstrous to suppose that the terraces stretching on a dead level for leagues along the coast, & miles in breadth, & covered with beds of stratified gravel 10–30 feet in thickness, are due to subaerial denudation.3
As for the pond of salt water, twice or thrice the density of sea-water, & nearly dry, containing sea-shells in same relative proportions as on the adjoining coast, it almost passes my belief.4 Could there have been a lively midshipman on board, who in the morning stocked the pool from the adjoining coast?
As for glaciation I will not venture to express any opinion, for when in S. America I knew nothing about glaciers, & perhaps attributed much icebergs which ought to be attributed to glaciers.5 On the other hand Agassiz seems to me mad about glaciers, & apparently never thinks of drift ice.— I did see one clear case of former greater extension of a glacier in T. del Fuego.—6
I hope that you are enjoying your holiday.
My dear Lyell | Yours affectionately | Ch. Darwin
Comments on enclosed discussion of S. American geology by Agassiz. Mentions elevation of Patagonia and glaciation.