ht of it came
back with gathering strength, and he wondered whether it could possibly be
true.

Advancing with every possible precaution, they gained the summit and
passed on down the other side. Before them lay the desert, glittering and
glowing in the morning sun, without a sign of alien presence. Keeping a
sharp lookout, they reached the little, half-circular recess in the cliffs
that formed the end of the trail, and paused.

No rain had fallen in the last ten days and the print of motor-tires was
almost as clear and unmistakable as the day it had been made. They could
make out easily where the car had been driven in, the footprints about it,
and the marks left by its turning; and with equal lack of difficulty they
picked out the track made as it departed.

The latter headed north, but Stratton was not interested in it. Without
hesitation he selected the incoming trail, and the two followed it out
into the desert. For a few hundred yards they rode almost due east. Then
the wheel-marks turned abruptly to the south, and a little further on Buck
noted the prints of a galloping horse beside them.

"Lynch, I reckon," he commented, pointing them out to his companion. "When
he saw me up on the cliffs down yonder, he must have hustled to catch up
with the car."

Neither of them spoke again until they reached the spot where Buck had
seen the car stop and the men get out and walk about. Here they dismounted
and followed the footprints with careful scrutiny. Bud saw nothing
significant, and when they had covered the ground thoroughly, he expressed
his disappointment freely. Stratton merely shrugged his shoulders.

"We'll follow the back track and see where else they stopped," he said
curtly.

His voice was a little hoarse, and there was an odd gleam in his eyes.
When they were in the saddle again, he urged his horse forward at a speed
which presently brought a protest from Jessup.

"Yuh better take it easy, old man," he cautioned. "If that cayuse steps in
a hole, you're apt to get a jolt that'll put you out of business."

"I don't guess it'll hurt me," returned Stratton with preoccupied
brevity.

Bud gave a resigned shrug, and for ten minutes the silence remained
unbroken. Then all at once Buck gave a muttered exclamation and pulled
his horse up with a jerk.

They were on the rim of a wide, shallow depression in the sand. There was
nothing remarkable about it at first sight, save, perhaps, the total
absence of des