all the individuals of the same species should have a continuous distribution. On this latter branch of the subject I have put a chapter together, and Hooker kindly read it over. I thought the exceptions and difficulties were so great that on the whole the balance weighed against my notions, but I was much pleased to find that it seemed to have considerable weight with Hooker, who said he had never been so much staggered about the permanence of species.
I must say one word more in justification (for I feel sure that your tendency will be to despise me and my crotchets), that all my notions about HOW species change are derived from long continued study of the works of (and converse with) agriculturists and horticulturists; and I believe I see my way pretty clearly on the means used by nature to change her species and ADAPT them to the wondrous and exquisitely beautiful contingencies to which every living being is exposed...
CHARLES DARWIN TO J.D. HOOKER. Down, July 30th 1856.
My dear Hooker,
Your letter is of MUCH value to me. I was not able to get a definite answer from Lyell (On the continental extensions of Forbes and others.), as you will see in the enclosed letters, though I inferred that he thought nothing of my arguments. Had it not been for this correspondence, I should have written sadly too strongly. You may rely on it I shall put my doubts moderately. There never was such a predicament as mine: here you continental extensionists would remove enormous difficulties opposed to me, and yet I cannot honestly admit the doctrine, and must therefore say so. I cannot get over the fact that not a fragment of secondary or palaeozoic rock has been found on any island above 500 or 600 miles from a mainland. You rather misunderstand me when you think I doubt the POSSIBILITY of subsidence of 20,000 or 30,000 feet; it is only probability, considering such evidence as we have independently