“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?” “Why, I kicked it,” said Jim. “A good thing it’s so big: I always thought Norah gave it to you with the idea that you might club a few Germans with it, if you got the chance—and scalp ’em afterwards. Get out!—” as Wally tipped his cap off. “Remember that you’re in a subterranean locality, and behave as such. Hark at that echo!” He had raised his voice, unwittingly, and the echo had sent it shrieking round the cave. It was quite a relief when the sound died away to a low murmur. “I’m not at all sure that it isn’t the Bunyip, an’ he livin’ here at his aise, as Con would say,” Wally muttered. “Come on; we’ll see how far this place goes.” The light grew dimmer as they moved on, away from the crack overhead. Fortunately, Jim was never to be found without a tiny electric torch in his pocket, and its little beam of light was sufficiently to guide them. But for the torch their explorations would certainly have come to an end immediately, for it was not half a minute before they found themselves against a wall that apparently ended the cave. “Well, it isn’t much of a cavern, after all,” Jim remarked. “Not bad as a dressing-room for Norah, if she wants to bathe from this beach—there’s clear sand right down to the water from the entrance in one place. She will have to come at low tide, though.”