The retreating tide had left deep pools behind, each a little cosmos of fairy seaweeds and tiny scuttling crabs and rich and wonderful forms of life which were strange to me. Crusoe and I were very much interested, and lingered a good deal on the way. But at last we reached the great archway, and passed with a suddenness which was like a plunge into cool water from the hot glare of the tropic sunshine into the green shadow of the cavern. At the lower end, between the two arches, a black, water-worn rock paving rang under one's feet. Further in under the point the floor of the cave was covered with white sand. All the great shadowy place was murmuring like a vast sea-shell. Beyond the southern archway spread the limitless heaving plain of the Pacific. Near at hand bare black rocks rose from the surges, like skeletons of the land that the sea had devoured. And after a while these walls that supported the cavern roof would be nibbled away, and the roof would fall, and the waves roar victorious over the ruins. I wished I could visit the place in darkness. It would be thrice as mysterious, filled with its hollow whispering echoes, as in the day. I dreamed of it as it might have been when a boat from the _Bonny Lass_ crept in, and the faint winking eye of a lantern struck a gleam from the dark waters and showed nothing all around but blackness, and more blackness. From the ledge far above my head led off those narrow, teasing crevices in which the three explorers did their unrewarded burrowing. I could see the strands of a rope ladder lying coiled at the edge of the shelf, where it was secured by spikes. The men dragged down the ladder with a boat-hook when they wanted to ascend. I looked about with a hope that perhaps they had left the boat-hook somewhere. I found no boat-hook but instead a spade, which had been driven deep into the sand and left, too firmly imbedded for the tide to bear away. At once a burning hope that I, alone and unassisted, might bring to light the treasure of the Bonny Lass seethed in my veins. I jerked the spade loose and fell to. I now discovered the great truth that digging for treasure is the most thrilling and absorbing occupation known to man. Time ceased to be, and the weight of the damp and close-packed sand seemed, that of feathers. This temporary state of exaltation passed, to be sure, and the sand got very heavy, and my back ached, but still I dug. Crusoe watched proceedings interestedly at first, then wandered off on business of his own. Presently he returned and began to fuss about and bark. He was a restless little beast, wanting to be always on the move. He came and tugged at my skirt, uttering an uneasy whine.