It must have been somewhere toward five o'clock in the afternoon that Dean, searching with his field glass the sunlit slopes far out to the east, heard the voice of his sergeant close at hand and turned to answer. Up to this moment, beyond the pony tracks, not a sign had they seen of hostile Indians, but the buffalo that had appeared in scattered herds along their line of march were shy and scary, and old hands said that that meant they had recently been hunted hard. Moreover, this was not a section favored of the buffalo. There was much alkali and sage brush along their trail, and only here and there in scanty patches any of the rich, nutritious bunch grass which the roving animals so eagerly sought. The day had been hot and almost cloudless. The shimmer of heat along the lazy roll of the land to the south had often baffled their blinking eyes. But now the sun was well to the west, and the refraction seemed diminishing, and away over to the northeast a dull-colored cloud seemed slowly rising beyond the ridges. It was this that Sergeant Bruce was studying when he murmured to his young commander: "I think that means a big herd on the run, sir, and if so Indians started them." One or two troopers, dozing close at hand, sprawled full length upon the ground, with their faces buried in, or hidden by, their blue-sleeved arms, slowly rolled over and came crouching up alongside. Dean dropped his glasses and peered in the direction indicated by his comrade of humbler rank. Dust cloud it was beyond a doubt, and a long peep through the binocular proved that it was slowly sailing across the horizon in a northerly direction. Did that mean that the red hunters were driving the great quarry toward the village of the Sioux, or that the young men were out in force, and with the full complement of squaws and ponies, were slaughtering on the run. If the former, then Dean and his party would be wise to turn eastward and cross the trail of the chase. If the latter they would stand better chance of slipping through to the Gap by pushing northward, deeper in among the pine-crested heights.