ed like
marble.

"Now we are really in the tunnel," declared Ned. "I wonder what's at
the end?"

"The city of gold, of course," answered Tom confidently.

Eagerly they hurried on. There was a slightly musty smell to the
air, but it was fresher than might have been expected.

Suddenly Tom, who was in advance, uttered a cry. It sounded like one
of alarm, and Ned yelled:

"What's the matter?"

"Look here!" cried Tom. They hurried up to him, to find him standing
before a sort of niche in the wall. And the niche was lined with a
yellow metal that gleamed like gold, while in it was one of the
golden images, the second one they had seen, and the third they
heard about.

"We're on the trail! We're on the trail!" cried Tom.

"Heah! Let me hab dat!" cried Eradicate. "I may not git anudder,"
and he reached up for the statue.

"Let it stay until we come back," suggested Mr. Damon.

"Somebody might take it," said the colored man.

"Who?" laughed Tom. "There's not a soul here but ourselves. But take
it, if you want it, Rad," and Eradicate did so, stuffing the image,
which was only about four inches high, into his pocket.

Then they went on, and they saw several other images, though not of
gold. Several niches were lined with yellow metal, but whether it
was gold or not they could not tell. They did not want to stop, as
they were anxious to get to the underground city.

"Hark! What's that?" asked Tom, when they had gone about a mile
along the tunnel. "Don't you hear something?"

"Sounds like a roaring," agreed Ned. "Maybe it's more of the bats."

"Doesn't sound like bats," declared Tom. "It's more like a
waterfall. Come on."

They hurried forward, the strange sound increasing at every step,
until it filled the tunnel with its menacing roar.

"That's strange," said Tom in worried tones. "I hope we don't come
to a waterfall."

Suddenly the tunnel made a turn, and as they went around the curve
in the wall the sound smote on their ears with increased violence.
Tom raced forward, focusing his electric lamp down on the stone
corridor. The next instant he cried out:

"A river! It's an underground river and we can't go any further!
We're blocked!"

The others came to his side, and there, in the glare of their lamps,
they saw rushing along, between two walls of stone, a dark stream
which caused the roaring sound that had come to them. The tunnel was
cut squarely in two by the stream, which was at least thirty feet