On a narrow ledge, some four feet down from the terrace-level, and directly beneath the extensive crack that had once been formed in the massive upheaval of tufa, the broken fragments that blocked the subterranean hallway were wedged to their places in the wall. The place was sunk in a shallow niche that was screened by the trees of the jungle.
This ledge Grenville not only promptly rendered accessible, but, after the opening had once been cleared, he fashioned a door of the lightest construction, that still resembled solid rock, with which to conceal it again.
His door was of wattle, plastered with clay, which he then thrust full of tufa fragments. These, when the substance presently hardened, were found to be substantially cemented to the framework. The clay itself dried yellowish gray and could hardly be distinguished from the rock. He was thus enabled to plaster over all the chinks and other ragged openings which the door could not completely cover. When the job was done, not the faintest suspicion of anything unusual about the niche could the keenest eye have discovered. Grenville was none the less glad, however, that the tallest foliage of the near-by growth still further concealed the spot.
He was toiling no less feverishly than before, thankful each day that the tidal wailing still continued and anxiously watching the round of the purple horizon for the cut of a rakish sail.
Despite the fact that several days had passed since the passage was discovered, he had made no effort to return to the treasure crypt below. The communicating gallery was too important to be neglected. He had spent long hours in its upper reaches, clearing the rock from underfoot, to make its use entirely practical for Elaine and himself in all conditions, either with or without some needed burden.
He had managed to widen the narrowest squeeze by chipping the rock with his chisel. He had carefully rearranged the broken fragments down where the corridor entered, or branched from, the cavern, and there provided a second of his wattle doors, considerably heavier than the first and more artfully studded with stone. This he had made to be adjusted from without or within the passage it concealed. From within it could also be barred in place with a heavy billet of the toughest wood his brazen tools would shape.
This late afternoon, when the last of his jugs had been taken down and concealed by the spring, all ready for filling and carrying back the moment occasion should arise, Grenville felt that, save for a meat supply, he had made nearly every possible provision against attack and siege.
The day was practically spent. He glanced at the sun. Undecided between an hour of hunting with his bow and a quick excursion down to the crypt of treasure, he remembered certain ornaments Elaine might wear and decided to go for the gold and gleaming jewels. They had meat for dinner, already being roasted in a sandpit with several newly gathered yams.
Elaine, with a basket of tempting fruits, returned to the terrace from the thicket before he was ready for his trip. The fact that he bore a torch and basket aroused no query in her mind, so frequently had he made his underground excursions.
He left the door at the gallery entrance open and made an easy descent. Glad to be independent of both the tide and his raft, he paused when he came to the main cave's ragged opening, for a moment thoroughly startled.