he
earth. There wasn't no wagon there a second ago."

CHAPTER XXX: ON THE EDGE OF THE CLIFF

For a moment both men suspected that what they looked upon was a
mirage--its actual existence there in that place seemed impossible.
Yet there was no disputing the fact, that yonder in the very midst of
that desolation of sand, a wagon drawn by straining horses was slowly
moving directly toward them. Westcott was first to grasp the truth,
hastily jerking the marshal back to where the tired ponies stood with
drooping heads behind the protection of the dune.

"It's the same outfit coming back," he explained. "The Sunken Valley
must be out there--just a hole in the surface of the desert--and that's
how that wagon popped up out of the earth the way it did. I couldn't
believe my eyes."

"Nor me neither," and the marshal drew one of his guns, and held it
dangling in his hand. "I'm a bit flustered yet, but I reckon that's
about the truth. Get them ponies round a bit more, an' we'll wait and
see what's behind that canvas."

The distance must have been farther than it seemed, or else the
travelling difficult, for it was some time before the heavy wagon and
straining team drew near enough for the two watchers to determine
definitely the character of the outfit. Westcott lay outstretched on
the far side of the dune, his hat beside him, and his eyes barely able
to peer over the summit, ready to report observations to the marshal
crouched below.

"It's Moore's team, all right," he whispered back, "and Matt is driving
them. There isn't any one else on the seat, so I guess he must be
alone."

"We can't be sure of that," returned Brennan, wise in guarding against
surprises. "There was another fellow with him on the out trip, and he
might be lying down back in the wagon. We'd better both of us hold 'em
up. I can hear the creak of the wheels now, so maybe you best slide
down. Is the outfit loaded?"

"Travelling light, I should say," and Westcott, after one more glance,
crept down the sand-heap and joined the waiting man below. Both stood
intent and ready, revolvers drawn, listening. The heavy wheels grated
in the sand, the driver whistling to while away the dreary pull and the
horses breathing heavily. Moore pulled them up with a jerk, as two
figures leaped into view, his whistle coming to an abrupt pause.

"Hell's fire!" was all he said, staring dumbly down into Brennan's face
over the front wheel. "Where in Sam