Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/363

350 from the old, and favours the notion that the coast-line of a post-miocene European land would be somewhere in the central Atlantic, about the position of the great Fucus Bank. The probability of the ancient existence of such a land is further borne out by the fact that the floras of the groups of islands between the gulf-weed bank and the mainland of the Old World are all members of one flora, itself a member of the Mediterranean type, and only peculiar inasmuch as certain endemic species are present, many of which are common to the Azores, Madeira and the Canaries.

Having broached these views at the late Cambridge meeting of the British Association, I have had an opportunity of hearing and considering such objections as have been offered against them. Such as have been offered against the premises assumed, are sufficientiy met by the preliminary observations on specific centres, which are also equally applicable to a proposition which has been made to account for the peculiarities of the British floras, by transmutation from marine into terrestrial species within given areas, though a knowledge of the submarine vegetation of the areas in question would have prevented such hypothesis ever having been broached. A more serious objection is that which asserts that a more extended view of the distribution of animals and plants will, so far from supporting, offer numerous difficulties to the theory which I have brought forward to account for the origin of our British fauna and flora. These, however, I have well considered, and have not as yet found any which at all invalidate my views, but, on the contrary, to render probable their general application. Whilst it is very probable that in the present state of the inquiry—its infancy, in fact—there are many of my data insecure and likely to require considerable modification hereaiter, the great leading principle, I firmly believe, will stand the strictest investigation, and prove as true when tested by an appeal to the distribution of organized beings, as well fossil as recent, over the whole globe—as well during the several geological epochs of ancient times as in that in which we live, as it appears to be when applied to the limited area under consideration.

My main position may be stated in the abstract, as follows:—

The specific identity, to any extent, of the flora and fauna of one area with those of another, depends on both areas forming, or having formed, part of the same specific centre, or on their having derived their animal and vegetable population by transmission, through migration, over continuous or closely contiguous land, aided, in the case of alpine floras, by transportation on floating masses of ice.

The question of the general origin of alpine floras and faunas is, perhaps, the most important inquiry which such a position can affect, and may be regarded, in a great measure, as a fair test of its truth. If the