There was no telling what had brought the troop of horsemen to a halt, but after a time Kirby knew that the cause of his horse's sudden departure must have been a whiff of the strange perfume. * * * * * For a long time he stood still, watching the crazy stallion dwindle in size, watching the line of unexpectedly timid bandits. Then, when it became apparent that the horsemen were going to stay put either until he came out, or showed that he never was coming out, he shrugged, and swung on his heel so that he faced up the canyon. The odor was dying away now, and the geyser rumble was gone. In Kirby's heart came a mingled feeling of tense uneasiness and fascinated curiosity. Momentarily he was almost glad that his horse _had_ bolted, and that his pursuers _were_ blocking any lane of retreat except that offered by the canyon. If things had been different, the queer behavior of the Mexicans, the unaccountable actions of his horse and the equally strange growth of his own uneasiness might have made him uncertain whether he would go up the canyon or not. Now it was the only thing to do, and Kirby was glad because, fear or no fear, he wanted to go on. "I wonder," he said out loud as he started, "just what the denizens of First Street in Kansas would say to a layout like this!" CHAPTER II At the end of an hour he was still wondering. At midday the canyon was chill and dank, lit only by a half light which at times dwindled to a deep dusk as the rock walls beetled together hundreds of feet above his head. Always when he stumbled through one of the darkest passages, he heard and half saw immense gray bats flapping above him. In the half-lit reaches, he hardly took a step without seeing great rats with gray coats, yellow teeth, and evil pink eyes. But rats and bats combined were not as bad as the snakes. They were almost white, and nowhere had he seen rattlers of such size. If his caution relaxed for a second, they struck at him with fangs as long and sharp as needles. The tortured, twisted cedars, the paloverdi, occatilla, cholla, opunti, through which he edged his laborious way, all offered an almost animate, armed hostility. Altogether this journey was the least sweet he had taken anywhere. Yet he went on. Why had eleven Mexican bandits refused to advance even to within decent rifle range of the canyon's mouth? What was there about the putrid yet gorgeous perfume that had made the stallion go off his nut, so to speak? After a time, Kirby veered away from a fourteen-foot rattler which flashed in a loathsome coil on his left hand. Hungry, weakened by all he had been through since breakfast time, he plodded doggedly on. But a moment later he stumbled past a twisted cedar, and then stopped, forgetting even the snakes. At his feet lay the bleached skeleton of a man. * * * * *