P. S.I omitted to mention that my pickets on the Williamsburg road cut off a lieutenant and corporal of cavalry, who were on the advance of the mounted force which drove in my l)ickets. These pris- oners have been turned over to the provost-marshal of the division, Captain Young. No. 3. Report of Afaj. John D. Moriarty, Seventy-third New York Infantry. HDQRS. FOURTh REGIMENT, EXCELSIOR BRIGADE, Camp Seven Pines, Va., June 15, 1862. LIEUTENANT: I would respectfully report: Upon the morning of the 14th instant my regiment relieved the First Regiment of this brigade (Major bIt) upon picket duty in the front of th~ lines and redoubt upon the left of the Williamsburg road. The picket was posted from the left, where they connected with those from General Kearnys division to the right across the Williamsburg road and there joined those of Gen- eral Sumner. During the early part of the day a change was made by the order of General Sickles, commanding, with the sanction of General Hooker, commanding division at the left, where the picket was. Instead of being placed around a point of wood (swampy), they were carried through the wood at the junction of the road running from the left of the redoubt in nearly a straight line to a l)oint designated as the pine tree, by which a large portion of the left, nearly upon the flank of General Kearnys division, was relieved, and the safety of that portion of the line enhanced. The line was well guarded up to and including the junction with the picket of General Sumner. 1)uring the morning shells were thrown from the redoubt of the enemy, also from two field batteries; several of them passing into our redoubts. At about 12 m. the picket upon the front was established about 100 yards to the front, by the sanction of the general commandin g. This was done only after making a thorough reconnaissance from the look- oat, the beech tree (in front), as also by personal reports of Captain McCauley, Company H, and Captain Smith, Company B. During the afternoon the enemy pressed upon the right of our line in large force, both cavalry and infantry, driving in my pickets (two companies, coin- manded by Lieutenant Stewart, Company G, amid Lieutenant Bowermuan, Company E), and almost immediately they threw a large force of in- thutry upon our whole line of pickets. Our pickets held their ground n)antully until, the force of the enemy being increased, they were com- l)elled to fall back in front of the fallen timber, where as they came in 1 formed them, amid from time to time, until relieved by the Fifth New Jersey Regiment, sent portions again into the wood, eimdeavoring to regain and ii old our lost ground. We were finally compelled to fall back to the road in fromit of the abatis, and there held our position. I am fully convinced the force sent to hold this front is entirely inade- quate for the purpose. There should not be less than 1,000 men placed in the position with any probability of holding to the outer edge of the wood in front. Very respectfully, J. D. MORIARTY, Major, Comdg. Picket, Fourth Regiment, Excelsior Brigade. Lient. II. E. TREMAIN, Acting Assistant Adjutant-General.