matter?" exclaimed Dick. "Do you see him?"

"No! But look!" went on Bud. "We have come out into a regular
underground cave! It's as big as a house!"

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.

CHAPTER XXII

THE WATER GATE

While they eagerly watched, the solitary figure on the big rock in the
midst of that sinister pool again moved slightly, and as it became
partly erect it was seen to be Nort Shannon.

"We've found him! We've found him!" joyfully cried Dick.

"An' alive, too, if I'm any judge," added Billee.

Dick was stripping off his coat, when Bud placed a hand on his shoulder.

"Wait a minute," advised the western lad.

"But I'm going to get him!" objected the brother. "I'm going to save
Nort!"

"Maybe it isn't safe, and we may be able to save him in another way,"
suggested Bud. "I say, Nort," he called. "Are you hurt?"

How eagerly they all waited for the answer, after the echo of Bud's
voice had ceased reverberating in the big cave!

"Yes--I--I'm all right," came the faint answer across the silent pool.
"I don't know exactly how I got here. Something hit me on the
head--after I fell--fell in. I reckon I must have floated near this
rock and--and just naturally grabbed hold and--pulled myself--up!"

"That's enough! Take it easy now!" called Bud. "We're coming over to
get you!"

"Sure you're not hurt?" asked Dick, his voice trembling.

"Nothing more than a bump on the head