This was one of the first times the United States Army had been able to use artillery against the Indians in the Southwest. Roberts ordered his infantry to take the hills overlooking the pass, while he remained in the pass to direct the artillery support. The skirmishers moved forward, where they were able to take cover in an abandoned Butterfield Overland Mail station. The soldiers were now about 600 yards from the spring. Overlooking the spring were two hills, one on the east, the other on the south. The Apache riflemen behind the breastworks on the hills were delivering a deadly fire against the attackers.