In an hour or so--perhaps in two hours--Sanderson would crawl out of his blanket, get his own breakfast, and ride northeastward. He was a free agent now, and would be until he rode in to the Double A to assume his new duties. Judging by the light, Sanderson had slept a full hour when he again awakened. He stretched, yawned, and grinned at the brown horse. "You're still a-goin' it, Streak, eh?" he said, aloud. "I'd say you've got a medium appetite. There's times when I envy you quite considerable." Reluctantly Sanderson sat up and looked around. He had pitched his camp at the edge of a thicket of alder and aspen near a narrow stream of water in a big arroyo. Fifty feet from the camp rose the sloping north wall of the arroyo, with some dwarf spruce trees fringing its edge. Sanderson had taken a look at the section of country visible from the arroyo edge before pitching his camp. There were featureless sand hills and a wide stretch of desert. Sanderson started to get to his feet. Then he sat down again, stiffening slowly, his right hand slipping quickly to the butt of the pistol at his right hip. His chin went forward, his lips straightened, and his eyes gleamed with cold alertness. A horseman had appeared from somewhere in the vast space beyond the arroyo edge. Sanderson saw the outlines of animal and rider as they appeared for an instant, partly screened from him by the trees and undergrowth on the arroyo edge. Then horse and rider vanished, going northward, away from the arroyo, silently, swiftly. Schooled to caution by his long experience in a section of country where violence and sudden death were not even noteworthy incidents of life, and where a man's safety depended entirely upon his own vigilance and wisdom, Sanderson got up carefully, making no noise, slipped around the thicket of alder, crouched behind a convenient rock, huge and jagged, and waited. Perhaps the incident was closed. The rider might be innocent of any evil intentions; he might by this time be riding straight away from the arroyo. That was for Sanderson to determine. The rider of the horse--a black one--had seemed to be riding stealthily, leaning forward over the black horse's mane as though desirous of concealing his movements as much as possible. From whom? It had seemed that he feared Sanderson would see him; that he had misjudged his distance from the gully--thinking he was far enough away to escape observation, and yet not quite certain, crouching in the saddle to be on the safe side in case he was nearer than he had thought. Sanderson waited--for only a few minutes actually, but the time seemed longer. Then, just when he was mentally debating an impulse to climb to the top of the gully, to see if the rider was in sight, he heard a sound as of a heavy body crashing through some underbrush, and saw two riders skirting the edge of the arroyo near him.