In descending from the ice-cavern, along the very ridge of lava that had issued from its site, the gradual change in aspect of its material was interesting; not only from the rolled and worn look of its earlier and now lower portions, but from the alteration of colour and quality. At the cavern itself, the substance was of a bluish grey in the mass, amazingly tough and of basaltic consistence; while lower down the stream, it became black, then brownish-black, somewhat cindery and brittle; this portion having been indeed the scum that the volcanic vent had first poured out.

Amongst other fragments met with, were occasional specimens having one or more sides as smooth, as if they had been polished. This was no result of simple fracture,—for of all the blocks which we broke by hammer, there was not one that did not show a rough, granular, though sometimes glossy surface. We were puzzled by those smooth natural faces, for they neither arose from the material being vitreous, nor from any result of rubbing and grinding; but of this we were quite certain, that they served admirably to display the laminated nature of the lava.

Perceiving presently a heavy lump, rather bigger than a man's head, excellently illustrative of the contortions of said laminæ, we picked it up as a prize specimen of the first class; but had no sooner done so, than the Canarian youth attending us, though loaded already with a box of chemicals and a photographic tent, prayed for his right of place to carry it.