.

For at least thirty minutes they hastened onward, and then the Westerner
found a place where the horses could climb the sloping wall of the
ravine and get out of the gorge. It was no easy task to make the animals
struggle to the top, but Bushnell succeeded in forcing them all up. When
the party was out of the ravine every one breathed with greater freedom.

"There," said Frank, "I do not feel as if we might be caught like rats
in a trap."

Frank was the last to move from the ravine, and, just as he was about to
do so, he seemed to catch a glimpse of something moving silently in the
darkness.

"Hist!" came the warning from his lips. "Come here, Bushnell--professor,
Hans, stay with the horses. Be cautious, and come lively."

He flung himself on his face in the shadow of a great bowlder, and
peered down into the darkness below.

The Westerner and the professor came creeping to his side.

"What is it?" asked Bushnell.

"Look," directed Frank. "What do you make of it?"

Peering down into the dark depths of the gorge, they saw black figures
flitting silently past, men and horses, as they were able to make out.

"Horsemen!" breathed the professor. "They must be the bandits!"

"But look!" came cautiously from Frank's lips; "they are riding swiftly,
yet the feet of their horses make no sound!"

"That's right!" gasped Scotch. "Great Jupiter! can they be more ghosts?"

"Mysteries are crowding each other," said Frank.

Bushnell was silent, but he was watching and listening.

Like a band of black phantoms, the silent horsemen rode along the ravine
and disappeared. Frank could hear the professor's teeth chattering as if
the man had a chill.

"This bub-bub-beats my tut-tut-tut-time!" confessed Scotch. "I rather
think we'd better turn back and let the Silver Palace alone."

"Rot!" growled Bushnell. "Them varmints wuz Pacheco's gang, an' they hed
the feet of their critters muffled, thet's all. Don't git leery fer
thet. All ther same, ef Jack Burk or his spook hedn't warned us, them
onery skunks w'u'd hed us in a consarned bad trap."

This was the truth, as they all knew, and they were decidedly thankful
to the mysterious individual who had warned them.

Bushnell now resorted to the trick of "covering the trail," in order to
do which it was necessary to muffle the feet of their horses and lead
them over the rocky ground, where their bandaged hoofs could make no
mark. At length he came to a stream, and he led the