HEADQUARTERS ARMY OF THE POTOMAC, June 2, 1863.

Brigadier-General BUFORD,
Commanding, &c., Bealeton:

A report reaches here that three brigades of enemy's cavalry have gone into Shenandoah Vallery. It is not known here what foundation exists for the rumor, nor, if true, what the purpose of the move is- whether to make a raid, and,if so, in what direction, or to cover and conceal the movement of other troops. The general would like to have you keep him fully advised, not only with regard to the presence of the enemy in his front, but, if not there, whereabouts and his movements. The general expects you to aid in fixing the locality and numbers of the enemy's cavalry especially, with a view to our future movements. Send uss by telegraph all the news obtained, and have scouting parties active. The capture of prisoners, contrabands, &c., may give much information. They may have moved down the Rappahannock to intercept Kilkpatrick who is busy in the vicinity of the Piankatank.

By command of Major-General Hooker:

S. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS THIRD CORPS PICKETS, June 2, 1863-10 a. m.

Colonel O. H. HART,
Assistant Adjutant-General, Third Corps:

I have the honor to report that since my report of the morning the enemy's cavalry and artillery have been observed moving toward Fredericksburg, perhaps two or three squadrons of cavalry and not less than a battery of artillery. It was but at one point they were in sight, and they passed very rapidly.

Very respectfully, your obedient servant,

H. BERDAN,

Colonel, Commanding.

YORKTOWN, VA., June 2, 1863.

Major-General HOOKER:

It seems apparent from the rumors that reach me that a movement of rebel troops is going on from south to north, and that the idea prevails over the lines that an invasion of Maryland and Pennsylvania is soon to be made. I have heard nothing definite, but all the rumors concur to produce the impression stated.

E. D. KEYES.

BALTIMORE, June 2, 1863.

Brigadier-General KELLEY,

Harper's Ferry:

Received the following from Milroy:

A number of reports have come in this evening that the rebs have returned to the Valley with much increased force, and are about to attack this place. My cavalry had a skirmish with the rebel cavalry and infantry at Strasburg this morning, and left them in possession of that place, it being the advance of their force, said to be 10,000