[64] Assuming the Helix Lowei and Bowdichiana to be gigantic phases of the H. Portosanctana and punctulata, respectively; four only, namely H. fluctuosa and lapicida, Achatina Eulina, and Cyclostoma lucidum (the first three of which are extinct throughout the entire group), seem to have altogether disappeared. Nevertheless, the gradual dying-out, as it were, of species, both here and in Madeira proper, is singularly evident. Thus, in the latter, the Caniçal beds show the H. tiarella to have been once most abundant (it literally teems in those calcareous formations). Yet so rare is it in a recent state, that, until the summer of 1855, when it was detected by myself and the Rev. R. T. Lowe in two remote spots along the perpendicular cliffs of the northern coast, it was supposed to have been lost for ages. And the same may be said of its counterpart, the H. coronata, in Porto Santo,—which, likewise, swarms in every fossil-bed of that island; but which was, also, until I met with it, on the 15th of December 1848, adhering to slabs of stone at a considerable depth beneath the ground, on the extreme eastern peak (opposite to the Ilheo de Cima), imagined to have long passed away. And so, reasoning from analogy, I think it far from improbable that the third representative of this little geographical assemblage,—the H. coronula of the Bugio (which has hitherto only occurred in the mud deposits on the summit of that rock),—may be still alive, though perhaps in very small numbers, on some of the inaccessible ridges of those dangerous heights.
[65] Origin of the Fauna and Flora of the British Isles (in Mem. of the Geol. Survey of Great Britain, vol. i. p. 336, a.d. 1846).
[66] "My own belief," says Professor Forbes, "is, that the great belt of gulf-weed, ranging between the 15th and 45th degrees of north latitude, and constant in its place, marks the position of the coast-line of that ancient land."
[67] Although, for want of a better name, it may be admissible, when speaking either figuratively or poetically, to allude to this former region (as I have done in the above quotation) under the title of "Atlantis;" yet it seems incredible that certain writers (assuming its quondam existence) should have recently referred to it seriously as the possible "Atlantis of the ancients!" Considering that there is good reason to believe that all these islands were islands in a miocene sea, and that, if (through a general elevation) they were subsequently connected, the land of passage was broken up long anterior to the appearance of man upon the earth, "the ancients" must have assuredly merited their appellation, if they could have thrown any light on a problem which belongs to an epoch thus remote. Whether the "Atlantis" had any being at all except in the imagination of the Latin poets, or whether (as Lord Bacon has suggested) it was the New World, will probably never now be known; yet the fact that the Insulæ Fortunatæ of Juba are almost universally identified with the present Canarian Group (as indeed the accurate description of Pliny well nigh demonstrates), and the Purpurariæ with the Madeiras, ought at once, apart from geological evidence, to point out the absurdity of the hypothesis, that an Atlantic continent, in the very position which those islands occupy, could have been acknowledged to have any existence by the literature of either Rome or Greece.
[68] Insecta Maderensia, p. 214.
[69] Journal of Researches, pp. 326, 327.
[70] Many of the Calosomata would appear to possess this power of crossing, either by flight or by abandoning themselves to the waves (though more probably by the assistance of both), even marine barriers with impunity. Numerous instances are on record to this effect; and I am informed by Mr. Darwin that a Calosoma flew on board the 'Beagle,' off the Bay of San Blas, in South America, whilst they were ten miles from shore. It seems likely, therefore, that the occasional occurrence of the C. Syncophanta in our own country, along the southern and eastern coasts, is due to this generic capability,—and consequently (as indeed it is usually acknowledged to be), the result of accident.
[71] Introduction to Entomology, ii. p. 13.
[72] Principles of Geology, 9th ed. p. 657.
[73] Although this is true on a broad scale, a reference to my observations in a preceding chapter will show, that in some countries, especially islands, the reverse will frequently be found to obtain.