At last he thought of the rock where he had first concealed himself. Such rocks were numerous, too; but pulling out his ease of crayons, he marked the base of the rock with a small streak of colour. Finally, remembering that the drift sand might cover this mark so made, he drew out his penknife, and made a large cross in the hard sand. Having taken these precautions, he made the best of his way down to the cliffs, and following the open green sward which fringed the crags, made the best of his way home to the caravan. At daybreak the next day he strolled back along the crags, first taking a bird’s-eye view of the village; and perceiving no sight of William Jones, who had doubtless no suspicion that he would rise so early, he soon found the spot where he had stood overnight, watching the approach of the boat; and first reconnoitring the neighbourhood, struck off among the sand-hills. At first he was guided by footprints, but as the sand grew harder, these disappeared. At length, after a somewhat bewildering search, he found the sandhill he sought, the rock with his mark upon it, the cross marked in the ground, and finally, the well-concealed mouth of the hole. He looked keenly to right and left. No one was visible. Stooping down he displaced the stones and loose sand, and disclosed the trap-door with its iron ring. A long pull, a strong pull, and up came the trap. Open Sesame! Behind him was a dark cavity, with a slanting path descending into the bowels of the earth. Anxious to lose no time, he squeezed himself through the aperture, and began descending. While he did so he heard the hollow roaring he had heard the night before. As he proceeded he drew out a box of matches and a candle, which he lit. Proceeding cautiously on his back, and restraining himself with his elbows from too rapid descent, he found himself surrounded not by sand, but by solid rock, and peering downward, saw that he was looking down into a large subterranean cave. Just beneath him was a flight of steps cut in the solid. Descending these carefully, for they were slippery as ice, he reached the bottom, and found it formed of sea-gravel and loose shells, forming indeed a decline like the sea-shore itself, to the edge of which, filling about half the cavern, the waters of the sea crept with a long monotonous moan. Approaching the water’s edge he saw facing him the solid walls of the cliff, but just at the base there was an opening, a sort of slit, almost touching the waves at all times, quite touching them when the swell rose, and through this opening crept beams of daylight, turning the waves to a clear malachite green. The mystery was now clear enough. The cave communicated directly with the sea, but in such a way as to make an entrance for any large object impossible from that direction.