aal ordered one of the Gorols to bring a bundle of torches and told
Kurt and Kurul to stay where they were and look after Dan, who was
stretched out in a happy doze.

But as Dick rose to go, Dan started after him. "I wasn't sleeping," he
cried. "I just closed my eyes to think! I'm going along."

"What's the matter?"

"Nothing. I'd just feel better to go with you."

"You're not afraid, are you?" laughed Dick. "The Gorols are all
friendly."

"Of course not. But I was just thinking, suppose that old
witch-doctor, Cimbula, happened to smell the cooking and crash the
party. He might persuade those fellows to throw me into the Boiling
Spring after all."

"Well, come along, if you're able to walk," answered Dick.

They followed the winding trail to the hot sulphur spring that still
sent its suffocating fumes from the black pit and bubbled menacingly as
the boys looked down.

"Jiminy crickets! I'll never forget how they wanted to chuck me in
there," exclaimed Dan. "Walk a little faster!"

"Come along. There's the cave mouth just ahead."

The chums paused to stare at the tall posts that marked the entrance,
each crowned with a polished human skull, then Raal got the torches
flaring and passed them out to light their way.

Dick followed close beside Raal, with Dan at his heels, as they plunged
into the darkness of the cave. The narrow walls rose straight beside
them as they proceeded slowly, and soon Dick reached the place where
the passage turned at right angles.

Here the walls were flat surfaces, smoothed and cut artificially. It
was no longer a rugged cave but a tunnel.

"Look!" exclaimed Dan. "The walls are all covered with drawings."

Dick held up his torch to the rocky surface and saw that it was painted
with pictures of hunting scenes, men pursuing boars and antelope. The
drawings were done in outline and rubbed with some brownish color to
make them show clearly.

"These are real Stone-Age pictures," said Dick as they went deeper and
deeper into the cave. "They are like the ones that Umba is painting
now in his cave, but they show animals that have died out long ago.
See, here are drawings of extinct animals. There is the sabre-tooth
tiger. And look, that is a mastodon with long, curved tusks."

"Jiminy, wouldn't it be wonderful if we could find one or two left
over?" said Dan.

"A mastodon? Not likely! The climate has changed since the time that
picture was made and those giants d