s were on both sides,
and most of them sticking up from five to ten feet above his head.

"It wouldn't be any fun if some of those loose rocks came down on a
fellow's head, or on his horse," mused our hero, as he moved along. "I
wonder where this way leads to?"

At a distance he could hear the others talking, so he knew they were not
far off. They, too, were now among the big rocks, and each hidden from
the others. Then the talking gradually ceased, giving way to an
occasional call or whistle.

"Oh, if only I could just stumble into the entrance to that mine!"
thought Dave. "What a fine thing it would be for Roger and his family! I
know they need the money!"

He kept his eyes on the alert, but none of the signs for which he was
searching appeared, nor did anything that looked like a mine entrance
show itself.

It was growing towards sunset when Dave, who had just met Phil and
separated from him, came to another rocky defile, this time leading to
something of a hollow. Here the air was damp and cool and our hero
paused for a moment, for he felt tired and hot after the hard riding of
the day.

"Wonder where we will camp for to-night," he mused, as he gazed around
him. "I hope we find some nicer spot than this. This looks so lonely and
spookish. Well, I suppose I've got to go on, or they'll get ahead of
me, and it would be no fun to get lost. A fellow----"

Dave came to a stop in his musings and also drew up his horse. He had
taken but a few steps farther, and now saw, to one side of the rocky
defile, a small opening, leading into a sort of hill.

"Looks as if it might be a kind of cave," he told himself. "I guess I'd
better dismount and take a look inside. It might be the entrance to the
lost mine!"

Suiting the action to the word, Dave leaped from his horse, and letting
the steed stand, approached the cave. The entrance was comparatively
small and he had to stoop down to peer inside.

As he did this there came a sudden ominous growl from the interior of
the cave. It was the growl of a wild beast and caused the youth to leap
back in alarm. Then a slinking body came into view and a full-sized
mountain lion showed himself!

Dave ran toward his horse. But as the mountain lion gave another growl,
the horse snorted and plunged, in sudden fright. Then the steed took to
his heels and went clattering along the rocky defile.

"Stop!" yelled the youth. "Stop!" And then he set up a call for
assistance.

At the soun