Second Brigade, Colonel Stainrok, One hundred and ninth Pennsylvania commanding: One hundred and eleventh Pennsylvania Volunteers, Major T. M. Walker commanding; Third Maryland Volunteers, Lieutenant Colonel Sudsburg commanding; One hundred and ninth Pennsylvania Volunteers, Colonel Stainrook commanding (detached and not in action); One hundred and second New York Volunteers, Lieutenant Colonel J. C. Lane commanding.

Third Brigade, Colonel Goodrich, Sixtieth New York Volunteers, commanding: Sixtieth New York Volunteers, Lieutenant-Colonel Brundage commanding; Seventy-eighth New York Volunteers, Lieutenant-Colonel austin commanding; Third Delaware Volunteers, Major A. Maginnis commanding.

The First District of Columbia Volunteers, nominally attache to this brigade has wholly disappeared from the command by desertion and sickness.

About 2 o'clock the night before the action, the corps took up position about 1 1/2 miles in rear of General Hooker's corps, near the farm of J. Poffenberger, bivouacking in columns of companies. At the first sound of cannon at daylight on the morning of the 17th instant, the command wa shut in movement, each regiment by order of General Mansfield, marching in column of companies, closed in mass. In this order the corps moved to the front by battalions in mass, the First Brigade, First Division, Leading, over ground of intermingled woods, plowed fields, and corn-fields. Before reaching the position of General Hooker's corps, information was brought that his reserves were all engaged and that he was hard pressed by the enemy. The columns were hastened up and deployed in line of battle with all the rapidity that circumstances would permit. Five of the regiments of the First Division were new and wholly without drill.

The massed battalions had been moved with such haste that the proper intervals for deployment had not been carefully attended to. The old regiments, however, deployed promptly, and the new regiments (both officers and men of which behaved with marked coolness) soon got into line of battle, with more promptitude than could have been expected.

While the deployment was going on, and before the leading regiments were fairly engaged, it was reported to me that the veteran and distinguished commander of the corps was mortally wounded. I at once reported to Major-General Hooker on the field, took from him such directions as the pressing exigencies would permit, and hastened to make a disposition of the corps to meet them. Crawford's brigade was directed to deploy to the right, its right regiment extending to the Williamsport [Hagerstown] and Sharpsburg stone pike. Gordon held the center, while Brigadier-General Greene's division, following the first division in column, was directed to the ridge on the left, extending its line from the lane on Fordon's left to the burned buildings, a few rods northerly of the brick church.

While General Greene was moving into position, I was strongly solicited by Brigadier-General Gibbon to sent re-enforcement to the right to support General Doubleday's position. I accordingly detached the Third Brigade of General Greene's division, with orders to report to any general found on the field indicated. At the same time I ordered the One hundred and twenty-fourth Pennsylvania Volunteers (Crawford's brigade) to push forward past the farm-house of Mr. Miller, cross the pike into the woods beyond, and hold the ridge as long as practicable.