text: Oak Grove McClellan planned to advance to the west, along the axis of the Williamsburg Road, in the direction of Richmond. Between the two armies was a small, dense forest,  wide, bisected by the headwaters of White Oak Swamp. Two divisions of the III Corps were selected for the assault, commanded by Brig. Gens. Joseph Hooker and Philip Kearny. Facing them was the division of Confederate Maj. Gen. Benjamin Huger.
  Soon after 8 a.m., June 25, the Union brigades of Brig. Gens. Daniel E. Sickles (the Excelsior Brigade), Cuvier Grover, both of Hooker's division, and John C. Robinson stepped off. Although Robinson and Grover made good progress on the left and in the center, Sickles's New Yorkers encountered difficulties moving through their abatis, then through the upper portions of the creek, and finally met stiff Confederate resistance, all of which threw the Federal line out of alignment. Huger took advantage of the confusion by launching a counterattack with the brigade of Brig. Gen. Ambrose R. Wright against Grover's brigade. At a crucial moment in the battle, the 26th North Carolina of Brig. Gen. Robert Ransom's brigade, in their first combat engagement, delivered a perfectly synchronized volley of rifle fire against Sickles's brigade, breaking up its delayed attack and sending the 71st New York into a panicked retreat, which Sickles described as "disgraceful confusion."