of wood along, and made my discovery."

"And you say you're bound out now?" asked Frank.

"That's what we are, little Lopez and me; and we can't get to the open
any too soon, either, to please both of us," Smith replied, shouldering
his pack.

"Oh! say, Mr. Smith," cried Bob, "have you lost a pet that wears a
collar?"

"Meanin' my pet painter, Nero, I take it," replied the miner. "I
raised him up from a cub, and he's as fond of me as my dog. But he's
gone somewhar. We ain't seen him for hours, and like as not the
critter knowed it was gettin' dangerous in here. Trust animal sense
for that. But wait till this next whoop gets by, and then we'll make
for the door. Here's hopin' we'll all be smart enough to get to the
open. Bend your backs to the wind, boys; ye wont feel it so much
then," and all of them carried out his instructions as, with a rapidly
rising roar, the spouting geyser that played in the heart of Thunder
Mountain again started to break loose.

CHAPTER XX

TRAPPED IN A CANYON

Once the little party started toward the opening, they made rapid
progress. The turmoil was at their backs, for one thing. Then, again,
each time the noise broke forth it seemed so much worse than before,
that every one felt anxious to get beyond the portal of the cave before
the climax came.

And when finally this opened before them, Bob drew a long sigh of
relief.

"Glory!" he burst out. "Maybe I'm not glad we've arrived! But I
reckon your pet, Nero, has skipped, Mr. Smith, or he would have come
out when you and the little Lopez passed. Sorry for you; but perhaps
it's just as well for the rest of us; because you see the fellow might
have had it in for us."

So they passed into the outer air.

"Seems pretty much the same as when we left," remarked Bob, as he
stared up at the dark sky against which they could see the rocky crown
of Thunder Mountain dimly outlined.

"Why, what did you expect?" asked Frank.

"I didn't know but what some of that thunder might be the genuine
article, and we'd find the rain coming down to beat the band. Glad it
isn't, because we want to get down from this to where our horses are."

"Little Lopez has our burro and bronco quartered in a small ravine
where they can't escape," remarked the old miner, as he handed Frank
the lantern he had been carrying, the girl taking the other.

"But would they be in danger in case of a storm-burst?" asked Bob.

"We counted on that when w