its heights, and yet in
their various hiding-places there were scores, each with his deadly
rifle ready to send a return bullet for every one fired by an enemy.

"No firing unless absolutely necessary," was the Doctor's whispered
order; and then all was silent while they waited to see if any enemy
would really come.

They were not long kept in doubt, for just as the heavens had assumed
that peculiar rich grey tint that precedes darkness, and a soft white
mist was rising from the depths of the canyon, there was seen, as if
arising from out of the plain itself, a dark body moving rapidly, and
this soon developed itself into a strong band of Indians, all
well-mounted in their half-naked war costume, their heads decked with
feathers, and each armed with rifle and spear.

They were in their war-paint, but still they might be disposed to be
friendly; and the Doctor was willing to believe it till he saw through
his glass that they wore the skull and cross-bones painted in white upon
their broad, brown chests, and he knew that they were of the same tribe
as had visited them before, and gone off after so severe a lesson.

Still he hoped that they might be friendly, and he was determined that
they should not be fired upon without good reason.

A few minutes later he changed his opinion, for, evidently well-drilled
by their chief, the Indians charged towards where the tilted waggons
were drawn up in the shade of the rock, riding with as much precision as
a well-drilled body of cavalry. Then, at a sign, they drew rein in a
couple of ranks, about fifty yards from the waggons, and presenting
their rifles, without word of warning, fired a volley.

Another volley followed, and another, the thick smoke rising on the
evening air, and then, apparently surprised at there being no replying
shot, about twenty galloped up with lowered spears, thrust two or three
times through the canvas tilts, and galloped back, the whole band
sweeping off the next moment as swiftly and as silently as they came,
gradually becoming fainter and more shadowy, and then quite disappearing
from the watchers' sight.

"They're gone, then?" whispered Bart, drawing a breath of relief.

"Yes; they're a bit scared by the silence," said Joses; "but they'll
come back again."

"When?" said Bart.

"Sneaking about in the dark, to stampede the horses and cattle, as soon
as ever they know where they are, my boy."

"Yes--come back," said the Beaver in a low tone, a