I went up to it and searched among the creepers, but still could find no opening.
"Move the stone," cried Stella's voice, "the cave is shut with a stone." I took a spear and prodded at the cliff whence the sound came.

Suddenly the spear sunk in through a mass of lichen.

I swept the lichen aside, revealing a boulder that had been rolled into the mouth of an opening in the rock, which it fitted so accurately that, covered as it was by the overhanging lichen, it might well have escaped the keenest eye.

We dragged the boulder out; it was two men's work to do it.

Beyond was a narrow, water-worn passage, which I followed with a beating heart.
Presently the passage opened into a small cave, shaped like a pickle bottle, and coming to a neck at the top end.