It has always seemed to me rather strange that Forbes, Wollaston and Co.

should argue, from the presence of allied, and not identical species in islands, for the former continuity of land.
They argue, I suppose, from the species being allied in different regions of the same continent, though specifically distinct.

But I think one might on the creative doctrine argue with equal force in a directly reverse manner, and say that, as species are so often markedly distinct, yet allied, on islands, all our continents existed as islands first, and their inhabitants were first created on these islands, and since became mingled together, so as not to be so distinct as they now generally are on islands.
LETTER 115.

TO H.G.BRONN.

Down, October 5th [1860].
I ought to apologise for troubling you, but I have at last carefully read your excellent criticisms on my book.