Complex sentence: While the Americans were discussing this development, Alexander McKee arrived with about 140 Shawnees under the leadership of Blacksnake, who took up a position to Crawford's south, effectively surrounding the Americans.
Split into simpler sentences: While the Americans were discussing this development, Alexander McKee arrived with about 140 Shawnees under the leadership of Blacksnake. The Shawnees took up a position to Crawford's south, effectively surrounding the Americans.