CHAPTER XVIII.
OCTOBER 31st to NOVEMBER 5th .-- Our first proceeding on the morning of the 31st was to make the proposed tour of the reef, which is about a quarter of a mile long.

With the aid of our sounding-lines we found that the water was deep, right up to the very rocks, and that no shelving shores prevented us coasting along them.

There was not a shadow of doubt as to the rock being of purely volcanic origin, upheaved by some mighty subterranean convulsion.

It is formed of blocks of basalt, arranged in perfect order, of which the regular prisms give the whole mass the effect of being one gigantic crystal; and the remarkable transparency of the sea enabled us plainly to observe the curious shafts of the prismatic columns that support the marvelous substructure.
"This is indeed a singular island," said M.Letourneur; "evidently it is of quite a recent origin." "Yes, father," said Andre, "and I should think it has been caused by a phenomenon similar to those which produced the Julia Island, off the coast of Sicily, or the group of the Santorini, in the Grecian Archipelago.

One could almost fancy that it had been created expressly for the 'Chancellor' to stand upon." "It is very certain," I observed, "that some upheaving has lately taken place.