our march was renewed daily without noticeable incident until Sunday 14th instant, when we arrived at South Mountain, and engaged the enemy. At 3 o'clock we marched up the Hagerstown road, leading over the mountain, most to its summit, and there formed line of battle, to support other lines then engaged. At about 3.30 o'clock I advanced, by your orders, to the top of the heights m advance of our other forces, and was unexpectedly fired upon from the woods by a large force of my new regiments. it quickly recovered, however, reforming under a severe fire. My command then advanced, and after a long and hard fight, lasting until 9 p. m., drove the enemy from their position and occupied the field. We retained possession of the battle-field during the night, having our whole force on guard, momentarily expecting a renewal of the attack.

The enemy posted their pickets within a few yards of our lines, and during the night quietly withdrew their main body. We captured above 100 prisoners.

In this battle all the troops of my command behaved with the greatest bravery. I have to mention as worthy of particular praise the conduct of the Fifty-first New York Volunteers, commanded by Lieutenant Colonel R. B. Potter; the Fifty-first Pennsylvania Volunteers, commanded by Colonel J. F. Hartranft, and the Twenty-first Massachusetts Volunteers, commanded by Colonel W. S. Clark. Colonel E. A. Wild, of the Thirty-fifth Massachusetts Volunteers, was wounded severely in the arm while forming his regiment under the enemy's fire.

I append a list of the killed and wounded in this engagement, amounting to 10 killed, 83 wounded, 23 missing; total, 116.

On the 15th instant, at 1 o'clock, we resumed our march in pursuit of the enemy, coming up with them near Antietam Creek, and bivouacking in front of their lines. During the morning of the 16th we remained in line of battle, the shells from the enemy dropping thickly in our midst. At 2 o'clock we changed front, moving nearer to the creek, in readiness to attack the enemy in the morning.

On the morning of the 17th at about 9 o'clock, by your order, I advanced my forces toward the stone bridge crossing Antietam Creek, a bridge naturally almost impregnable, and very strongly fortified by the enemy. We formed line of battle in a corn-field near the bridge, and awaited the result of the attack of some of our other forces that had preceded my brigade in the attempt to cross the creek. The passage of the bridge was, however, very obstinately disputed, and at length I received orders from you to move forward my brigade, and carry the bridge at all hazards. I accordingly moved forward my command, and carried the bridge at the point of the bayonet at 1 o'clock, losing in doing so a large number of officers and men. The Fifty-first Pennsylvania Volunteers, commanded by Colonel J. F. Hartranft, led the charge, followed by the Fifty-first New york Volunteers, Lieutenant Colonel R. B. Potter; the Third-fifth Massachusetts Volunteers, Lieutenant Colonel Carruth, and the Twenty-first Massachusetts Volunteers, Colonel W. S. Clark.

After carrying the bridge I moved forward one regiment to the summit of the hill, to retain the position gained until re-enforcements should arrive, holding the rest of my command on the banks of the creek.

During the afternoon, the enemy being re-enforced, and with heavy supports of artillery, advanced to drive our forces from their position. According to your orders, I moved forward my brigade to resist this movement, and, forming line, advanced under a storm of shot and shell. My troops, when entering this second battle, were nearly out of ammu-