Alden was not yet out of sight of the Indian when he emitted a series of tremulous whoops, the like of which the rider had never before heard on his journey across the plains. The first sound was an explosive shout, and the half dozen which succeeded trailed off into silence. The redskin made this strange outcry three times and then ceased. “I suppose he means that as a reply to my salute,” laughed Alden, who the next minute whisked beyond view around a turn in the gorge. “If I knew how to reply I should do so, but we’ll have to wait till next time.” Dick showed no disposition to slacken his pace and his rider did not restrain him. Just after making the turn referred to Alden turned his head. What led him to do so he could not explain since he knew he was clear of the warrior whom he had nearly scared out of his wits, but he saw an amazing sight. The varying character of the gorge showed a projecting mass of stone on the right near the top. It was at a wide part of the ravine, and the peculiar shape of the rocks left a partial cavity behind the jutting portion large enough to hold several persons. And in this depression three Indians, looking much like the one he had left out of sight, had evidently just risen from the ground and stood motionless as if watching him as he skurried from them. They must have been there when he rode beneath within fifty feet of where they were lying in ambush. Alden was dumfounded. What could it all mean? After watching and probably signaling they had waited till he rode right into the trap and then had allowed him to ride out again, unharmed and all unsuspicious of his peril. “That is too much for me,” mused the perplexed youth; “I spared one of them when I had him dead to rights, but why should those three spare me? That isn’t the way――” Could those odd sounding signals which the single warrior sent forward from his perch on the rocks have had anything to do with it? Did they cause the forbearance of his comrades farther up the gorge? That such should be the case seemed incredible, but days afterward Alden submitted the question to Shagbark. The veteran stroked his whiskers, puffed his pipe for a minute, and then squinted one eye. “Thar’s only one way to explanify it,” he answered; “the varmint whose scalp ye left on top of his head was so thankful that he signaled ahead to the other three varmints not to hurt ye, ’cause ye and him war friends. “I’ll own that that ain’t the gin’ral style of the critters, but sometimes they act jest as if they war white men, and better than _some_ white men I’ve met.” CHAPTER XVII AT THE STATION Dick the pony held his swift gallop for a half mile farther, when he debouched into an open country, similar in many respects to that which he had left behind him. While it could not be called level, it showed no steep inclines and the masses of rocks and heaps of boulders were readily flanked by the superb courser.