“Well, there is light,” he said presently, sitting up. “I wonder if there’s some opening below, Wal?”
“Don’t know, but I’m going to see,” Wally answered. He swung himself over the edge of the flat rock and climbed down, followed by his chum. They hunted about the great pile, seeking for some opening that might explain the glimmer of daylight that had greeted them above.
On one side of the mass was the long stretch of rock from which they had first climbed up; but on the other they found smooth hard sand, only lately under water. There were openings here and there among the boulders, but they led to nothing, and had no communication with the upper air; they explored them in turn, but found no solution of the problem. Then, as Wally was backing out on hands and knees from one of these false scents, he heard a low whistle from Jim, and hurried round a boulder, to find him regarding what looked like a slit, about three feet high, between two masses of rock.
“There’s some sort of a cave in there,” Jim said. “I’ve been in a little way, and it looks rather interesting, so I came back for you. There’s light far above one’s head; I believe we’ll find your knife there.”
They crawled into the narrow passage. Almost immediately it turned, so sharply that a casual searcher might easily have been misled into thinking it ended: and then it widened and they found themselves in a long, narrow cave. They could see no roof; but far above, a faint bar of light glimmered, and made it possible to see where they were going. Underfoot was hard sand. The walls were dripping with wet and encrusted with seaweeds and limpets.
“This is a real sea-cave,” Wally said cheerfully.
An echo took his voice and went muttering round the rocks, the mutter rising at length almost to a cry. It was an eerie sound, in the wet dusk of the cave, with the dark smell of a submerged place in their nostrils; and the boys jumped.
“I guess this isn’t a place to raise one’s voice in,” Wally said, dropping his to a whisper. “That’s a nice, tame echo; I’d like to take it back to Billabong!”
“Would you!” uttered Jim, with feeling. “The blacks would say it was the Bunyip come back; and anyhow, you’d get into trouble for bringing out a prohibited immigrant.” He made a quick pounce on an object that glittered faintly on the sand. “There’s your knife, old man!”
“Bless you!” said Wally, thankfully receiving his property. “I say, what luck! and haven’t you the eye of a hawk?”