The corps will camp in position, and guard their camps. Corps commanders will send out scouts in their front as occasion offers, to bring in information. Strong exertions are required and must be made to prevent straggling. By command of Major-General MEADE:

S. F. BARSTOW,

Assistant Adjutant-General.

SPECIAL ORDERS, HEADQUARTERS CAVALRY CORPS,

Numbers 98.
Frederick, Md., June 28, 1863.

I. Brigadier General Wesley Merritt will report without delay to Brigadier General John Buford, commanding First Cavalry Division, for assignment.

II. The division of cavalry known as Stahel's division will hereafter be designated as the Third Division.

III. Brigadier General J. Kilpatrick, U. S. Volunteers, is assigned to the command of the Third Cavalry Division.

IV. Brigadier-General Copeland is assigned to duty with the Second Division, and will report to Brigadier-General Gregg without delay.

V. The Second Pennsylvania Cavalry, Colonel R. Butler Price, will report for duty to the headquarters of the Army of the Potomac.

VI. The following-named general officers are assigned to duty with the Third Division, and will report for duty to Brigadier-General Kilpatrick without delay: Brigadier General E. J. Farnsworth, U. S. Volunteers; Brigadier General G. A. Custer, U. S. Volunteers.

VII. The Third Division will be organized into two brigades, as follows: The First Vermont, the First [West] Virginia, the Eighteenth Pennsylvania, and the Fifth New York Regiments will compose the First Brigade, under command of Brigadier-General Farnsworth; the First. Fifth, Sixth, and Seventh Michigan Regiments will compose the Second Brigade, under command of Brigadier-General Custer.

VIII. Captain J. M. Robertson, commanding First Brigade, Horse Artillery, will assign two batteries to duty with the Third Division.

IX. The Michigan battery now on duty with the Third Division will report to Captain Robertson.

X. Brigadier-General Kilpatrick will put his command in condition for instant service. By command of Major-General Pleasonton:

A. J. ALEXANDER,

Chief of Staff, and Assistant Adjutant-General.

ARMY OF THE POTOMAC, June 28, 1863.

Brigadier-General GREGG,

Commanding Second Cavalry Division:

GENERAL: A brigade of rebel cavalry is reported having crossed the Potomac at Seneca Mills, and is making for the railroad between this and Baltimore, to destroy it. You will dispatch immediately two brigades and a battery down the turnpike to New Market and