"Indians!" he called to them as soon as they were within earshot. "But they don't seem to be on lookout for us at all. They're fooling with some buffalo over here." Crawling to the crest, leaving his hat behind, Dean peered over into the swale beyond and this was what he saw. Half a mile away to the east the low, concave sweep of the prairie was cut by the jagged banks and curves of a watercourse which drained the melting snows in earlier spring. Along the further bank a dozen buffalo were placidly grazing, unconscious of the fact that in the shallow, dry ravine itself half a dozen young Indians--Sioux, apparently--were lurking, awaiting the nearer coming of the herd, whose leaders, at least, were gradually approaching the edge. Away down to the northeast, toward the distant Powder River, the shallow stream bed trended, and, following the pointing finger of the scout who crawled to his side, Dean gazed and saw a confused mass of slowly moving objects, betrayed for miles by the light cloud of dust that hovered over them, covering many an acre of the prairie, stretching far away down the vale. Even before he could unsling his field glass and gaze, his plains-craft told him what was slowly, steadily approaching, as though to cross his front--an Indian village, a big one, on the move to the mountains, bound perhaps for the famous racecourse of the Sioux, a grand amphitheater in the southern hills. And even as they gazed, two tiny jets of flame and smoke shot from the ravine edge there below them, and before the dull reports could reach their ears the foremost bison dropped on his knees and then rolled over on the sod; and then came the order, at sound of which, back among the halted troopers, every carbine leaped from its socket. CHAPTER III.