The sides were now entirely uniform in substance, in colour, and in lateral direction, the material being a very black and shining granite, and the distance between the two sides, at all points facing each other, exactly twenty yards.

The precise formation of the chasm will be best understood by means of a delineation taken upon the spot; for I had luckily with me a pocketbook and pencil, which I preserved with great care through a long series of subsequent adventure, and to which I am indebted for memoranda of many subjects which would otherwise have been crowded from my remembrance.
This figure [No figures in text] gives the general outlines of the chasm, without the minor cavities in the sides, of which there were several, each cavity having a corresponding protuberance opposite.

The bottom of the gulf was covered to the depth of three or four inches with a powder almost impalpable, beneath which we found a continuation of the black granite.

To the right, at the lower extremity, will be noticed the appearance of a small opening; this is the fissure alluded to above, and to examine which more minutely than before was the object of our second visit.

We now pushed into it with vigor, cutting away a quantity of brambles which impeded us, and removing a vast heap of sharp flints somewhat resembling arrowheads in shape.