fling around, looking at the fire, and sitting
there smoking his little pipe, as though in satisfaction over having
struck such a profitable job so easily; but he gave no sign of holding
any intercourse with outsiders.

With the coming of morning they were once more on the way. Frank noticed
with considerable satisfaction that now they seemed to be beyond the
ordinary limit of the various trails taken by the regular tourist
parties.

They were walking along, about the middle of the morning, when they
found themselves in a lonely region, where the dim trail led along the
foot of rugged walls stretching up, red and apparently unscalable, to
the height of hundreds of feet.

Frank was craning his neck as he looked up overhead, wondering if it
could be possible that there was any sign of an abandoned cliff
dwellers' village there, when he saw something move, and at the same
instant he jumped forward to pull his chum violently back.

CHAPTER XVI

A WONDERFUL DISCOVERY

Bob opened his mouth to call out, and ask what was the matter, that his
chum had seized upon him so fiercely. But he held his breath, for
something came to pass just then that made words entirely unnecessary.

A huge rock seemed to slip from its notch up on the side of the cliff,
and come crashing down, loosening others on the way, until finally the
rush and roar almost partook of the nature of a small avalanche.

Charley Moi had skipped out in a lively manner, and thus managed to
avoid being caught. Bob stared at the pile of broken rock, about which
hung a little cloud of dust.

"Wow! that was as close a call as I ever hope to have, Frank!" he
exclaimed, with a little quiver to his voice.

Frank himself was a bit white, and his hand trembled as he laid it on
that of his chum.

"I just happened to be looking up, and saw it trembling on the break,"
he said. "Only for that we might have been underneath all that stuff."

"But did you notice the clever way Charley Moi avoided the deluge?" said
Bob, trying to smile, though he found it hard work.

"Yes, it's hard to catch a Chinaman napping, they say," Frank went on.
"Three times this very day I've heard the thunder of falling rocks, and
that was what kept me nervous; so I watched out above. And, Bob, it
seemed as though I must have seen that big rock just trembling as it
started to leave the face of the cliff."

"Well, all I can say then, is, that you jumped to the occasion mighty
well. Som