He flashed his lantern around in a circle, and as the others came up and stood beside him, at a spot where the passageway beside the stream widened, they saw that they had emerged into a great vault.
And as they stood there, awed and marveling, there came to them, above the rustle and whispering of the rushing waters, the sound of a human voice—it was as though someone, sorely hurt, had moaned.
"Listen!" cried Dick.
"Hold up your lanterns!" commanded Bud sharply.
As they raised them, throwing the combined light farther out across the stream that had widened into a pool in the vault, Dick uttered a cry.
"I see him! I see Nort!" yelled Dick. "There, on the rock!"
And he pointed to the huddled figure of some one on a great rock in the middle of the pool of black water, which seemed, a short distance from the inflowing stream, to be as quiet as a lake. And, as they watched in the gleam of the lights, the figure on the rock moved slightly.
"Nort! Nort!" cried Dick, and his voice was flung back in deafening echoes from the vaulted roof.