a point of the greatest interest in geology, to determine, whether any distinct line can really be drawn, between those concretions, unquestionably of modern formation, which occur immediately upon the shore; and other calcareous accumulations, very nearly resembling them, if not identical, both in the fossils they contain, and in the characters of the cementing substances, that are found in several countries, at considerable heights above the sea.

(Footnote.  Voyage 2 page 168, 169 to 216 etc.)

Dr. Buckland has described a breccia of modern formation, which occurs upon the shore at Madagascar, and consists of a firmly-compacted cream-coloured stone, composed of granular fragments of shells, agglutinated by a calcareous cement.* The stone of Guadaloupe, containing the human skeletons, is likewise of the same nature; and its very recent production cannot be doubted, since it contains fragments of stone axes, and of pottery.** The cemented shells of Bermuda, described by Captain Vetch,*** which pass gradually into a compact limestone, differ only in colour from the Guadaloupe stone; and agree with it, and with the calcareous breccia of Dirk Hartog’s Island, in the gradual melting down of the cement into the included portions, which is one of the most remarkable features of that rock.**** A calcareous compound, apparently of the same kind, has been recently mentioned, as of daily production in Anastasia Island, on the coast of East Florida;***** and will probably be found to be of very general occurrence in that quarter of the globe.  And Captain Beaufort’s account of the process by which the gravelly beach is cemented into stone, at Selinti, and several other places on the coast of Karamania, on the north-east of the Mediterranean,****** accords with M. Peron’s description of the progress from the loose and moveable sands of the dunes to solid masses of rock.******* In the island of Rhodes, also, there are hills of pudding-stone, of the same character, considerably elevated above the sea.  And Captain W.H.  Smyth, the author of Travels in Sicily, and of the Survey of the Mediterranean recently published by the Admiralty, informs me, that he has seen these concretions in Calabria, and on the coasts of the Adriatic; but still more remarkably in the narrow strip of recent land (called the Placca) which connects Leucadia, one of the Ionian Islands, with the continent, and so much resembles a work of art, that it has been considered as a Roman fabric.  The stone composing this isthmus is so compact, that the best mill-stones in the Ionian Islands are made from it; but it is in fact nothing more than gravel and sand cemented by calcareous matter, the accretion of which is supposed to be rapidly advancing at the present day.

(Footnote.  Geological Transactions volume 5 page 479.)

(**Footnote.  Linnean Transactions 12 page 53 to 57.)

(***Footnote.  Geological Transactions 2nd Series volume 1 page 172.)