CHAPTER XVII.
IN COLONEL MORELLO'S FORTRESS.
Directly ahead of them the gorge terminated abruptly in a blank wall of rock, in precisely the same manner that a blind alley in a city comes to a full stop. But "blank" in this case is a misnomer. The rocky rampart, which towered fully a hundred feet above the trail, was pierced with several small openings, which appeared to be windows. A larger opening was approached by a flight of steps, hewn out of the rock. Although Nat did not know it, the spot had once been a habitation of the mysterious aborigines of the Sierras. The colonel, stumbling upon it some years before, had at once recognized its possibilities as a fortress and a gathering place for his band, and had hastened to "move in." Stabling for the horses was found in a rocky chamber opening directly off the trail.
But Nat's wonderment was excited by another circumstance besides the sudden appearance of the rock fort. This was the strange manner in which the abyss terminated at the pierced cliff. As they came along, the boy had heard the sound of roaring waters at the bottom of the rift, and coupling this with the fact that the gorge emerged into the cliff at this point, he concluded that a subterranean river must wind its way beneath the colonel's unique dwelling place.
Small time, however, did he have for looking about him. About a hundred yards along the trail from the pierced cliff there was a strange contrivance extending outward from the face of the precipice along which the trail was cut. This was a sort of platform of pine trunks of great weight and thickness, on the top of which were piled several large boulders to add to the weight. This affair was suspended by chains and was an additional safeguard to the outlaws' hiding place. In the event of a sudden attack the chains were so arranged that they could be instantly cast loose. This allowed the platform to crash down, crushing whatever happened to be beneath it, as well as blocking the trail.
The colonel paused before they reached this, and whistled three times.
"Who is it?" came a voice, apparently issuing from a hole pierced in the rock at their left hand.
"Two Eagles of the Pass," came the reply from the colonel as he gave utterance to what was evidently a password.