..., drove back four distinct storming parties and held to their position amid the rocks and trees of the bluff overlooking the bridge. Finding he could not carry this by direct assault, Burnside sent Rodman 's division, by a wide detour to his left, to cross a lower ford of the Antietam and fall upon Toombs' flank. This forced the Georgians to retire, and at 1 o'clock Burnside began crossing the bridge...