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?"