HDQRS. CAVALRY FORCES, DEPARTMENT OF WASHINGTON, July 17, 1863.

Major-General PLEASONTON,
Commanding Cavalry Forces, Army of the Potomac:

GENERAL: I have received communications from you, ordering me to forward to you the men belonging to regiments of the corps, and who are at present included in my command. I have the honor respectfully to state the following grounds for this not having been done: When the cavalry of General Stuart passed north of this city, I was ordered by the General-in-Chief, through General Heintzelman, to gather together all the straggling cavalry in this vicinity, and to organize them for the defense of Washington. This I did, collecting some 3, 000 men, and in a week had armed, equipped, and mounted 2, 000 of them. As soon as the emergency was over, I was ordered to send a portion of these men forward to Frederick, where they were merged in your forces. The remainder, about 600 men, under Colonel Lowell, Second Massachusetts Cavalry, have been ordered to General King, to hold the Alexandria Railroad. As you will probably move toward them, these also will be added to your command. The men left with me are the sick and disabled and those not yet equipped for the field, excepting the few required to do picket and patrol duty around the defenses of this city. Thus, general, I have the honor to suggest that I have been carrying out as fully as possible the spirit of the orders contained in your communications. I would further suggest, that as a depot is thus formed here under my care, to which the men from hospitals and the camp of paroled prisoners can come and be equipped before joining their regiments, it would promote the efficiency of the cavalry if the dismounted men now with the army were sent here to be remounted and equipped. This can be done promptly now, and the men forwarded with greater speed and with less disorder than if they are left in the rear of the army, to have the horses and equipments forwarded to them. There are some new cavalry regiments expected here. When they arrive, all men belonging explanation may prove satisfactory, and the suggestion appended may receive your favorable consideration, I remain, general, very respectfully, your obedient servant,

P. WYNDHAM,

Colonel.

SPECIAL ORDERS, WAR DEPARTMENT, ADJT. GENERAL 'S OFFICE,

Numbers 316.
Washington, July 17, 1863.

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VI. Brigadier General J. S. Wadsworth, U. S. Volunteers, is relieved from duty with the Army of the Potomac, and has leave of absence until further orders.

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By order of the Secretary of War:

E. D. TOWNSEND,

Assistant Adjutant-General.