Two of the Pimas were scouting ahead on this two-day drive, and the Anglo riders were keeping the herd to a trot.
The Pimas were to warn the Anglo riders of any dangers along the way.
mnli hypothesis: The Pimas were to warn the Anglo riders of any dangers along the way. premise: Two of the Pimas were scouting ahead on this two-day drive, and the Anglo riders were keeping the herd to a trot.