Looking toward the canyon mouth which had swallowed their quarry, they certainly were, but they were halted as completely as men struck dead.
"Huh," Kirby grunted, and scratched behind his ear.
The next second he swung around to look at his horse, uncertain what he was going to do next, but aware of the fact that right now, with a lot of unknown country between himself and Castanar's sunlit patio, the stallion was going to be a friend in need.
As he turned, however, prepared to take up the loose reins, something else happened. The stallion let out a neigh as shrill as a trumpet blast. As Kirby jumped, grabbed for the bridle, his fingers found empty air. Like a crazy animal the stallion leaped past him, barely missing him. Out toward the plain the horse jumped, out and away from the shaded canyon mouth, out toward the spot where other horses waited. And despite the animal's blown condition, the speed he put into his retreat left Kirby dazed.
AFTER a helpless, profanity-filled second, Kirby scratched behind his ear again. As certain as the fact that almost his sole hope of getting back to civilization depended upon the stallion, was the fact that the brute did not intend to stop running until he dropped.
"Now what in the hell ever got into his crazy head?" Kirby muttered grimly.
Then he turned around to glance up the shadow-filled slash of a canyon, and sniffed.
"Huh!"
Faintly in the air had risen an odor the like of which he had never encountered in his life. A combination, it was, of the unforgetable stench which hangs over a battlefield when the dead are long unburied, and of a fragrance more rare, more heady, more poignantly sweet than any essence ever concocted by Parisian perfumer.
With the drifting scent came a sound. Faint, carrying from a distance, the rumble which Kirby heard was almost certainly that of a geyser.
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 dark-
