Believes CD's argument against special creation based on absence of terrestrial mammals on islands isolated before Pliocene era is very strong. However, the absence means Cetacea and bats have not modified towards terrestrial existence. There is similar lack of development of bats and rodents in Australia. Constancy among land shells of Madeira over long period shows that the majority of their species are immutable: a minority of "metamorphic" species maintains the overall number of true species while extinction removes many. Emphasis on the role of extinction discomfits CD's opponents since the power of generation of new species ought to keep pace. Mentions Ammonite deposits with reference to CD's comments on their apparent sudden extinction [Origin, pp. 321–2]. Perhaps absence of transmutation on slowly subsiding atolls indicates the slow rate of selective change.
Your argument from absence of mammalia in islands excepting those which we know to have
been joined to mainland in Pliocene times is a favourite one of mine when I wish to
prove that y
The land shells of Madeira and the Canaries are so endemic as to show that none were united with each other or Africa. I believe all were separate from Upper Miocene times; if not, small African species of quadrupeds would have been retained.
But the antiquity of islands void of mammals checks the hypothesis of the easy
adaptability of one species of a genus to new conditions. On a new volcanic island
before all the best places are seized upon, seals or walrus's, manatees, dolphins
& other cetacea, when pressed hard for food w
The long reign of the Dinornis family in New Zealand implies that for ages
there had been room for mammalia if bats & rodentia & aquatic placentals
being at hand had been convertible even into allied structures fitted for land habits.
And why bats & rodents should have peopled all Australia without having been
developed into something higher in the placental line seeing that the representatives of
the latter were imported from Europe, can run wild there, is strange, for why
As to the land shells of Madeira & Porto Santo 95 per cent of them have remained absolutely unchanged for a period sufficiently long to allow the form & size of the islands to be altered materially by the waves of the Atlantic, long enough for some species which once very common to become almost extinct—in a few quite lost
The only speculation I have been able to make is this that by far the majority
According to the progressive theory, why sh
Ammonites in uppermost part of the Maestricht, of a Cretaceous type, if not species of Texas are against the doctrine of wide gaps. Between Maestricht & Thanet sands.
What you say of the power of preoccupancy is good— so, as to atolls, but if they subsided very slowly, the absence of volant & amphibious forms of reptile & mammifer in such a region proves rate of transmutation slow, even as compared to revolutions in physical geography.
- f1 2908a.f1The text of the letter has been taken from a copy in Lyell's scientific journal. It is also printed in Wilson ed. 1970, pp. 472--4. The copy is headed: `C. Lyell to C. Darwin 8
thSept r. 1860— Coburg'.
- f2 2908a.f2See letter to Charles Lyell, 1 September .
- f3 2908a.f3Alfred Russel Wallace referred to the original form from which a variety or new species developed as the `antitype' (see Darwin and Wallace 1858, p. 61, and Wallace 1860, p. 181).
- f4 2908a.f4Lissencephala, in Richard Owen's classification of the Mammalia, was the division that included the rodents, insectivores, bats, and edentates. See R. Owen 1859a.
- f5 2908a.f5Lyell refers to the numbat or banded ant-eater, an Australian marsupial, and to the so-called Tasmanian wolf, a carnivorous marsupial.
- f6 2908a.f6Richard Thomas Lowe, an expert on the natural history of Madeira, published a description of the recent and fossil land and fresh-water shells of the island (Lowe 1854).
- f7 2908a.f7Bronn 1858a. See Junker 1991.
- f8 2908a.f8CD made this point in the concluding paragraphs of his letter to Charles Lyell, 1 September . See also Origin, p. 403.