“[D]efinitely undependable were the Pawnee, whose territory extended from the Big Blue Crossing to the forks of the Platte. The Kanzas, the Potawatomi, and the Sac and Fox were semi-civilized, at least to the point that there was some semblance of legality to their extraction of funds from the emigrants. The Pawnee were warriors and buffalo hunters who roamed their vast domain looking for trouble. They found plenty of it in the form of Sioux and Cheyenne to the west; and emigrants who had found themselves in the thick of tribal warfare on the Kansas River might have the experience repeated along the Little Blue and the Platte. . . . For the most part, however, the rumors of battles and massacres [between Pawnee and emigrants] were untrue, and the Pawnee merely threatened and blustered, demanding tribute of some kind for crossing their lands, although they would not be above robbing and sometimes murdering stragglers.”