. But the strangers, apparently unhurt, swept out
of sight.

Casey leaped to the ground, secured his rifle, and was back in the
saddle again in an instant. They sailed into the shallow head of the
coulee at a dead run, Casey struggling to refill the clip of his
automatic, McHale cursing his horse and himself because he had used the
rifle instead of his six-shooter.

At its head the coulee was merely a slight depression. Farther on it
broadened and deepened. Down the middle of its length ran a sinuous
grove of cottonwoods. On either side its flanks were bare, white with
clay and alkali, rising to steep banks of yellow earth, bald and
bleached in the moonlight.

Through this natural theatre thundered pursuers and pursued. The latter
had secured a good lead. The windings of the coulee hid them from view.

Suddenly Casey became aware that there was no one ahead--that he and
McHale were riding madly, to no purpose. At the same moment the latter
made the like discovery. Their horses' hoofs slid and cut grooves in
the earth as the riders dragged them to a halt. Usually considerate, in
the excitement of the moment they used the brutal methods of the
"buster."

"They've doubled back on us!" cried McHale. "Cut through them
cottonwoods somewheres and let us go by a-hellin'. Fooled us, by glory,
like we was a pair of hide-an'-go-seek kids. Yes--there they go now!
Look up by the top past that cut bank!" He lifted his rifle as he
spoke.

High up at the coulee's rim, some hundreds of yards away, figures
moved. At that distance, even in the brilliant moonlight, details were
lost. The eye could discern black spots merely; but it seemed that the
men had dismounted for the ascent, and were helping the horses to
scramble upward.

McHale fired, shoved down the lever, drew it home, and fired again.
Since the light did not serve to show the dust puffs of the bullets, he
could not tell whether he was shooting high or low. The main thing was
that he did not hit. Casey chimed in. The bluffs and banks echoed to
the reports of the high-powered rifles; but the figures gained the rim
and vanished. Immediately afterward a tongue of flame leaped from the
spot where they were last seen, and a bullet sang in close proximity to
Casey's head. They wheeled into the shelter of the trees, where the
shadows effectually concealed their whereabout. At short intervals
bullets searched for their position. McHale bit large consolation and
spat in disgust