New Hamsphire Volunteers, Major Smith; Eighty-first New York Volunteers, Captain Stimson; Ninety-eighth New York Volunteers, Major Rogers; One hundred and thirty-ninth New York Volunteers, Lieutenant Mulcahy-moved from camp at Fort Burnham, at 6 a.m. on the 26th instant, and bivouacked in a field near the Cox house, in rear of the headquarters of the Eighteenth Army Corps. At 5 a.m. on the 27th we took the advance in the march of the Eighteenth Army Corps, arriving at the New Market road at about 7 a.m. We continued the march northward, crossing the Darbytown and Charles City roads to the Williamsburg turnpike, which we struck near Seven Pines at about 1 p.m. At this point we threw out skirmishers and advanced in column to a piece of woods in front of the Seven Pines battle-field. Here the brigade was formed in line of battle and advanced through the woods to the center of an open field beyond. We came within range of the enemy's artillery fire from a line of works in our front. We were ordered to halt, and soon afterward moved by the right flank to a piece of woods on our right. We remained there until the Second Brigade, First Division, and other troops on their left, advanced in assault upon the enemy's position. We were then ordered forward to the edge of the woods, and near the enemy's line. Skirmishers were thrown out, and after driving in the enemy's skirmishers were actively employed in keeping down the enemy's fire upon our troops as they retired from their advanced position. At about this time the enemy placed a battery of three guns a little in advance of our right flank and about 800 yards distant. A vigorous fire was kept up by this battery, throwing shell and case-shot across our line. We moved to a more advanced position in advance, and by requiring the troops to lie down we escaped serious loss. At about 6 p.m. we were ordered to retire, and moved to the woods in rear of the field, and again formed a line of battle. About an hour afterward we moved again to the rear and marched to White's Tavern, on the Charles City road, where we halted.

The morning of the 28th, at daybreak, we advanced about a mile and formed a line across the Charles City road. At 10 a.m. we retired and marched across the Darbytown and New Market roads to our camp at Fort Burnham, where we arrived at about 6 p.m. on the 28th instant.

I regret to report the death of First Lieutenant William H. Alexander, of the One hundred and thirty-ninth New York Volunteers, a brave and efficient officer, who was killed by a solid shot on the afternoon of the 27th. Captain E. W. Goss, of the Thirteenth New Hamsphire Volunteers, commanding sharpshooters, and First Lieutenant Henry H. Murray, of the same regiment, acting on the staff of Colonel Cullen, commanding Second Brigade, are missing and supposed to be captured by the enemy.

Our loss in enlisted men is 8 wounded and 4 missing. The troops performed the march in the most creditable manner, and I am happy to state with a less number of stragglers than I have ever known on so fatiguing a movement.

I have the honor to be, captain, very respectfully, your obedient servant,

JOHN B. RAULSTON,

Lieutenant Colonel Eighty-first New York Vol. Infty., Commanding First Brigadier

Captain GEORGE A. BRUCE,

Acting Assistant Adjutant-General.