o that which they had been
following. The animals were cantering easily, when suddenly a deeper
gloom than usual overspread the valley like a pall. This came from a
heavy bank of clouds sweeping before the moon. The steeds were drawn
down to a walk, but the obscurity was not dense enough to shut out the
chasm-like opening, where the mountains seemed to part, riven by some
terrific convulsion ages before. The enormous walls drew back the door
as if to invite them to enter and press the pursuit of the couple that
were fleeing from a just and righteous wrath.

The width of the canyon had now dwindled to a few yards, and the stream
expanding and shallow, occupied so much of the space that the horses
were continually splashing through it, but the rise and fall of the
trail was so slight that the gallop might have continued with little
danger of mishap.

The formation of the party was in "Indian file," with Captain Dawson
leading, Ruggles next and Brush bringing up the rear. All three
animals were walking, for the light of the moon was variable and often
faint, while the danger of a mis-step was ever present, and was likely
to bring a fatal ending of the pursuit almost before it had fairly
begun. Occasionally the gloom in the narrow gorge was so deep that
they distinguished one another's figures indistinctly, but the animals
were left mostly to themselves. They seemed to know what was expected
of them and showed no hesitation. It was impossible for them to go
wrong, for it was much the same as if crossing a bridge, with its
protecting barrier on either hand. The horse of the captain showed his
self-confidence once or twice by a faint whinney and a break from the
walk into a trot, but his rider checked him.

"Not yet; heaven knows that I am as anxious to push on as you, but we
have already made one blunder and we can't afford another; when the
time comes that it is safe to trot you shall do so and perhaps run."

"Hush!" called Brush from the rear; "I hear a curious sound."

"What does it seem to be?"

"It is impossible to tell; let's stop for a moment."

As the three animals stood motionless, the strange noise was audible.
It was a deep, hollow roar rapidly increasing in volume and intensity,
and resembled the warning of a tornado or cyclone advancing through
the forest. The animals, as is the case at such times, were nervous
and frightened. They elevated their heads, pricked their ears, snuffed
the air and the animal