Edward Porter Alexander, Military memoirs of a Confederate: a critical narrative

Meanwhile the movement, though misunderstood, had been detected by the enemy.¹ About a mile southwest of Chancellorsville was a settlement called Hazel Grove, on a cleared ridge. From this ridge, about 8 A. M., Birney, of Sickles's corps, discovered a column of infantry, trains, and artillery passing his front. He brought up a battery and opened on the train at a range of 1600 yards, throwing it into much confusion, and compelling it to find other routes around the exposed point. Jackson sent a battery to reply and check the enemy from advancing. Sickles came to Birney's position and observed Jackson's column. His official report says:—

This continuous column — infantry, artillery, trains, and ambulances — was observed for three hours, moving apparently in a southerly direction toward Orange C. H., on the O. & A. R. R. or Louisa C. H. on the Va. Cen. The movement indicated a retreat on Gordonsville, or an attack upon our right flank — perhaps both, for if the attack failed, the retreat would be continued.

‘I hastened to report these movements, through staff-officers, to the general-in-chief, . . . to Maj.-Gen. Howard and also to Maj.-Gen. Slocum, inviting their cooperation in case the general-in-chief should authorize me to follow up the enemy and attack his columns. At noon I received orders to advance cautiously toward the road followed by the enemy, and attack his columns.’

Sickles advanced Birney's division, which engaged an outpost on the flank and captured a regiment, the 23d Ga. The two rear brigades, under Thomas and Archer, with Brown's battalion of artillery, were halted for an hour in observation, but were not engaged, and then followed on after the column. They were only able to overtake it, however, after night.

It was about 4 P. M. when the head of Jackson's column began its deployment on both sides of the Plank road, beyond Hooker's right, in the tangled forest; and it was nearly 6 P. M. when eight