The boys stared, marveling a moment, then Ted voiced his guess. The fossil of some giant of prehistoric ages! “A fossil, all right,” Ace agreed. “But that isn’t a human footprint, even if there had been men that size. That was made by some animal! If we ever get out of here, let’s bring Norris and come back with picks and find out.”
“Then I can quarry this fossil out and sell it?” ventured Ted.
“Right-o!” with a congratulatory slap that made Ted wince.
But the inky stream had once more become placid, and skirting the muddy ledge alongside, they threaded their way through arches of varying height till finally the roof was so low that they had to go on hands and knees. Then the bank became so narrow that Ace slipped off into the unknown depths. To his surprise, his feet touched bottom. Moreover, the water was not so cold as he had imagined. (It was about the same temperature as the air).
“Come on in, the water’s fine!” he encouraged Ted. “Do you know, we could swim this if we had to, and don’t you think it must lead out?”
“Stands to reason. But how about our candles?”
“Hold ’em in your teeth. Haven’t you ever seen any one smoke a cigarette when he was in swimming? It’s a stunt, but––”
“Ever tried it?”
“Sure. Have you?”
“No.” And the deepening water soon proved that he could not keep his candle going. But Ace managed it for a few strokes. Then they had to swim in darkness. An increasing roar told them that they were nearing white water, possibly the outlet, and just as the current from a branch stream would have caught them, they felt an overhanging ledge and scrambled up on it, Ace lending a hand to his less proficient chum.