“Well, that beats everything,” he said, with a perplexed sigh.  “That sounded so close that I expected to be run over before I could get out of the way, and now he’s gone.”

He waited some minutes, and, hearing and seeing nothing, once more resumed his stealthy way along the gorge, a new, shivering fear gradually creeping over him, as it does over anyone who suspects himself in the presence of the unexplainable and unnatural.

“I wonder whether they have ghosts in this part of the world?” he said to himself.  “I used to hear the men talk of such things, but father said there was nothing in them, and so I didn’t believe them—­but I don’t know what father would say or think if he was in my place.”

There was the strong counter-belief, also—­the conviction that most likely there was a reality about the thing—­which kept Fred on the qui vive.  He was determined, if possible, to prevent a repetition of the startling surprise of a few minutes before.  He scrutinized the side of the ravine as he walked along, on the lookout for any opening or crevice which would permit a man and a horse to find shelter.  It did not seem possible that any retreat that would shelter them could escape the eyes of the lad.

“I haven’t seen any such place yet, so, if the Indian is trying any such trick, he can’t do it here without my seeing him, and if I do—­Heaven save me!”

He sprang to one side, again pressing himself back against the rock, as though trying to flatten his body there in order to escape the trampling hoofs.  At the same time he cocked his rifle, with the purpose of giving the finishing touch to the Apache who had alarmed him once too often in this fashion.

CHAPTER XX AN UNCOMFORTABLE LODGING

A more astounding surprise than before awaited the lad.  His hair almost lifted itself as he found himself staring at vacancy, with no sign of a living person in sight.  Whatever had been the cause of this mysterious performance, it was very apparent that the solution rested not with the young fugitive.

“I’m tired of this,” he exclaimed, impatiently, after he had waited several minutes, “and it is n’t going to be played on me again.”

With this, he began clambering up out of the ravine, with the resolve to reach some place where no shadowy horseman could ride over him.

The climbing was difficult at first, but he soon reached a point where the inclination was not so steep, and where he could progress with much more ease and facility.  In this way he in time reached the upper level, and, believing himself out of range of his phantom pursuer, had time to look about for some sleeping-place for the night.

He frequently paused and listened, but could not see or hear anything of man or beast, and, confident that no danger was to be apprehended from either, he devoted himself to hunting for some refuge, that he could consider secure against molestation.  His first inclination was to seek out a place among the rocks, as he was likely to gain room where he could stretch out at his ease and enjoy a few hours’ slumber, but, on reflection, there were several objections to this.