ne far enough we'll turn north
and seek the ranges, where the cover is good. Now, hark to that, will
you!"

From a point to the northward rose a long, quavering shout, shrill in
its texture, and piercing the night like a call. A quiver ran along the
lad's spine.

"A Sioux made that cry!" he exclaimed.

"Beyond a doubt," replied Boyd, "but why he did so I can't tell. Wait."

They sat, silent, on their horses, and in a minute or two the cry was
repeated, but farther toward the east. Will could have mistaken the note
for the howl of a wolf, it contained so much animal quality, but since
the nature of the first had been told to him he knew that the second was
a reply to it.

"It's signals," said Boyd with conviction. "They're talking to one
another, though I don't know what they're saying. But it means the
sooner we get out of the valley the better for this white army of two."

"There's nothing to keep us from starting now."

"That's true. Because, if they find us here, all knowledge of the mine
for which we are looking is likely to perish with us. I don't suppose
the Sioux have made any formal declaration of war, but the warning of
Red Cloud is enough. They wouldn't hesitate to put out of the way two
wandering fellows like ourselves."

As they talked they rode slowly toward the west, the sound of their
horses' hoofs deadened on the turf, and both watching among the trees
for any hostile appearance. Young Clarke was rapidly learning the ways
of the wilderness, from experience, and also because he had in Boyd a
teacher not excelled anywhere in the West. The calls, the long, dying
cries, came again and again, showing the Sioux were steadily approaching
the valley, but the two were leaving it at an equal pace.

Will clutched the reins in his left hand and held the splendid repeating
rifle across the saddle bow with the other. The pack horse, unled, but
obedient to his training, followed close after. Boyd, just ahead of him,
proceeded in the same manner, and now they began to descend the slope
that ended in the open plain. In ten more minutes they would leave the
cover of the last tree. Before them rolled the bare country, swell on
swell, touched but faintly by the moon, yet keen eyes such as those of
the Sioux could trace the figures of horses and men on it for a
considerable distance.

Will felt little shivers as they were about to leave the final row of
trees. He could not help it, knowing that they were going to