We must try to get down to the bottom, and see if there's such a thing.

If there be, who knows but it may be big enough to let us out of our prison, without having to carve our way through the walls, which I feel certain would take us several days.

We must try to get down to the bottom." To accede to this request the guide needed no urging, and both--one after the other--at once commenced descending.
They found no great difficulty in getting down, any more than they had already experienced, for the shaft continued all the way down nearly the same width, and very similar to what it was above the ledge.

Near the bottom, however, it became abruptly wider by the retrocession of the walls.

They were now in a dilemma, for they had reached a point where they could go no further without dropping off.