as
cruel to put a horse to it. But Nagger was powerful, sure-footed, and
he would go anywhere that Slone led him. Gradually Slone worked down and
away from the bulging rim wall. It was hard, rough work, and risky
because it could not be accomplished slowly. Brush and rocks, loose
shale and weathered slope, long, dusty inclines of yellow earth, and
jumbles of stone--these made bad going for miles of slow, zigzag trail
down out of the cedars. Then the trail entered what appeared to be a
ravine.

That ravine became a canyon. At its head it was a dry wash, full of
gravel and rocks. It began to cut deep into the bowels of the earth. It
shut out sight of the surrounding walls and peaks. Water appeared from
under a cliff and, augmented by other springs, became a brook. Hot, dry,
and barren at its beginning, this cleft became cool and shady and
luxuriant with grass and flowers and amber moss with silver blossoms.
The rocks had changed color from yellow to deep red. Four hours of
turning and twisting, endlessly down and down, over bowlders and banks
and every conceivable roughness of earth and rock, finished the pack
mustang; and Slone mercifully left him in a long reach of canyon where
grass and water never failed. In this place Slone halted for the noon
hour, letting Nagger have his fill of the rich grazing. Nagger's three
days in grassy upland, despite the continuous travel by day, had
improved him. He looked fat, and Slone had not yet caught the horse
resting. Nagger was iron to endure. Here Slone left all the outfit
except what was on his saddle, and the sack containing the few pounds
of meat and supplies, and the two utensils. This sack he tied on the
back of his saddle, and resumed his journey.

Presently he came to a place where Wildfire had doubled on his trail and
had turned up a side canyon. The climb out was hard on Slone, if not on
Nagger. Once up, Slone found himself upon a wide, barren plateau of
glaring red rock and clumps of greasewood and cactus. The plateau was
miles wide, shut in by great walls and mesas of colored rock. The
afternoon sun beat down fiercely. A blast of wind, as if from a furnace,
swept across the plateau, and it was laden with red dust. Slone walked
here, where he could have ridden. And he made several miles of
up-and-down progress over this rough plateau. The great walls of the
opposite side of the canyon loomed appreciably closer. What, Slone
wondered, was at the bottom of this rent in th