A September sun, losing some of its heat if not its brilliance, was dropping low in the west over the black Colorado range. Purple haze began to thicken in the timbered notches. Gray foothills, round and billowy, rolled down from the higher country. They were smooth, sweeping, with long velvety slopes and isolated patches of aspens that blazed in autumn gold. Splotches of red vine colored the soft gray of sage. Old White Slides, a mountain scarred by avalanche, towered with bleak rocky peak above the valley, sheltering it from the north.