Hammilton`s Crossing. I have no information concerning the residue of the forces drawn from North Carolina. A. P. Hill`s corps is on the right, opposite to Franklin`s Crossing; Ewell`s is in rear of Fredericksburg, and Longstreet`s corps and the cavalry are at Culpeper. I have to-day dispatched the Third Corps to picket the river from Meade`s right, at Kell`s Ford, to Beverly Ford, in order to relieve the cavalry in aid of Pleaston, who is looking after the district of country from Beverly to Sulphur Springs. Pleaston is weak in cavalry compared with the enemy.

JOSEPH HOOKER,

Major-General.

JUNE 12, 1863-7 a. m. (Received 8. 40 a. m.)

Major General H. W. HALLECK:

It is reported to me from the balloon that several new rebel camps have made their appearance this morning. There can be no doubt but that the enemy has been greatly re-enforced

JOSEPH HOOKER

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC,
June 12, 1863-8. 30 a. m. (Received 8. 45 a. m.)

Major-General HALLECK

General-in-Chief General Pleaston, without additional cavalry, I fear will not be able to prevent the rebel cavalry from turning his right. I have not been able to ascertain his precise strength, but know that it is near 7, 500, while that of the enemy is certainly not less than 10, 000. He now pickets beyond Sulphur Springs. He will, however, do the best he can. If he should be turned, you will perceive that I shall be constrained to abandon the Aquia Creek line of operations.

JOSEPH HOOKER

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC,
June 12, 1863-1. 15 p. m. (Received 1. 40 p. m.)

Major General H. W. HALLECK,

General-in-Chief:

Learning that enemy had massed his cavalry near Culpeper for the purpose of a raid, I dispatched General Pleaston to attack him on his own ground. General Pleaston crossed the Rappahannock on the 9th, at Beverly and Kell`s Fords, attacked the enemy, and drove him 3 miles, capturing over 200 prisoners and one battleflag. This, in the face of vastly superior numbers, was only accomplished by hard and desperate fighting by our cavalry, for which they deserve much credit. Their morale is splendid. They made many hand-to-hand combats, always driving the enemy before them.

JOSEPH HOOKER,

Major-General.