overed; and, crouching within it, they could laugh to scorn the
storm that still came pouring from above; the stones, as they passed
close to their faces, hissing and hurtling like aerolites.

The rocky rain at length ended. The Indians had evidently come to the
conclusion that it was either barren in result, or must have effectually
performed the purpose intended by it, and for a short time there was
silence above and below.

They who were hidden in the shaft might have supposed that their
persecutors, satisfied at what they had accomplished, were returning to
the plain, and had retired from the spot.

Hamersley did think so; but Walt, an old prairie man, more skilled in
the Indian character, could not console himself with such a fancy.

"Ne'er a bit o' it," he whisperingly said to his companion. "They ain't
agoin' to leave us that easy--not if Horned Lizard be amongst 'em.
They'll either stay thar till we climb out agin, or try to smoke us. Ye
may take my word for it, Frank, thar's some'ut to come yet. Look up!
Didn't I tell ye so?"

Wilder drew back out of the narrow aperture, through which he had been
craning his neck and shoulders in order to get a view of what was
passing above.

The hole leading into the grotto that held them was barely large enough
to admit the body of a man. Hamersley took his place, and, turning his
eyes upward, at once saw what his comrade referred to. It was the smoke
of a fire, that appeared in the act of being kindled near the edge of
the aperture above. The smoke was ascending towards the sky, diagonally
drifting across the blue disc outlined by the rim of rock.

He had barely time to make the observation when a swishing sound
admonished him to draw back his head; then there passed before his face
a ruck of falling stalks and faggots. Some of them settled upon the
ledge, the rest sweeping on to the bottom of the abyss.

In a moment after the shaft was filled with smoke, but not that of an
ordinary wood fire. Even this would have been sufficient to stifle them
where they were; but the fumes now entering their nostrils were of a
kind to cause suffocation almost instantaneously.

The faggots set on fire were the stalks of the creosote plant--the
_ideodondo_ of the Mexican table lands, well known for its power to
cause asphyxia. Walt Wilder recognised it at the first whiff.

"It's the stink-weed!" he exclaimed. "That darned stink-weed o' New
Mexico! It'll kill us if we