ejoiced. Perhaps somewhere down in
this awful chasm he and Nagger would have it out with the stallion.
Slone began to look far ahead, beginning to believe that he might see
Wildfire. Twice he had seen Wildfire, but only at a distance. Then he
had resembled a running streak of fire, whence his name, which Slone
had given him.

This bare region of rock began to be cut up into gullies. It was
necessary to head them or to climb in and out. Miles of travel really
meant little progress straight ahead. But Slone kept on. He was hot and
Nagger was hot, and that made hard work easier. Sometimes on the wind
came a low thunder. Was it a storm or an avalanche slipping or falling
water? He could not tell. The sound was significant and haunting.

Of one thing he was sure--that he could not have found his back-trail.
But he divined he was never to retrace his steps on this journey. The
stretch of broken plateau before him grew wilder and bolder of outline,
darker in color, weirder in aspect, and progress across it grew slower,
more dangerous. There were many places Nagger should not have been put
to--where a slip meant a broken leg. But Slone could not turn back. And
something besides an indomitable spirit kept him going. Again the sound
resembling thunder assailed his ears, louder this time. The plateau
appeared to be ending in a series of great capes or promontories. Slone
feared he would soon come out upon a promontory from which he might see
the impossibility of further travel. He felt relieved down in the
gullies, where he could not see far. He climbed out of one, presently,
from which there extended a narrow ledge with a slant too perilous for
any horse. He stepped out upon that with far less confidence than
Nagger. To the right was a bulge of low wall, and a few feet to the
left a dark precipice. The trail here was faintly outlined, and it was
six inches wide and slanting as well. It seemed endless to Slone, that
ledge. He looked only down at his feet and listened to Nagger's steps.
The big horse trod carefully, but naturally, and he did not slip. That
ledge extended in a long curve, turning slowly away from the precipice,
and ascending a little at the further end. Slone, drew a deep breath of
relief when he led Nagger up on level rock.

Suddenly a strange yet familiar sound halted Slone, as if he had been
struck. The wild, shrill, high-pitched, piercing whistle of a stallion!
Nagger neighed a blast in reply and pounded the r