Complex sentence: He was reported as one of the first on the scene where Gorsuch and others of his party were attacked, and he and his horse provided cover for Dickerson, Gorsuch and Dr. Pearce, who were wounded.
Split into simpler sentences: He was reported as one of the first on the scene where Gorsuch and others of his party were attacked. Hanway and his horse provided cover for Dickerson, Gorsuch and Dr. Pearce, who were wounded.