Any reliable information which may be received from him or from members of Major Forbes' party who may return will at once be forwarded. We will doubtless have correct reports soon of the result.

This report has been delayed in expectation of getting accurate accounts. The necessary arrangements have been made here for the protection of property in case of an attack during Colonel Lowell's absence.

I have the honor to be, very respectfully, your obedient servant,

H. M. LAZELLE,

Colonel, Commanding Camp, Falls Church, Va.

Lieutenant Colonel JOSEPH H. TAYLOR,

Assistant Adjutant-General and Chief of Staff.

HEADQUARTERS CAVALRY BRIGADE,
Near Falls Church, Va., July 7, 1864.

COLONEL: I have the honor to report that lieutenant Kuhls, of the Second Massachusetts Cavalry, one of the officers, with Major Forbes' party, reached here this afternoon about 4 o'clock, being the only officer that has as yet returned. He reports our detachment badly beaten by the enemy in an engagement with a party of Mosby's men, estimated by him to number about 200, about half a mile this side of Mount Zion Church (near Aldie).

Of the party of 150 sent-out there have to-day returned to camp as follows: One officer and 26 men, Second Massachusetts Cavalry; 7 men, thirteenth New York Cavalry, the rest are missing. Lieutenant Kuhls thinks a few of them are either killed or wounded, but the majority taken prisoners. The particulars of the fight will be delayed until the return of Colonel Lowell, who will probably be able to give you more satisfactory accounts than I can.

The following officers were with the party and have not been heard from: First Lieutenant R. S. Schuyler, Thirteenth New York Cavalry; Second Lieutenant Michael Burns, Thirteenth New York Cavalry; Second Lieutenant Michael Burns, Thirteenth New York Cavalry; Chaplain C. A. Humphreys, Second Massachusetts Cavalry. Major Forbes, when last seen by Lieutenant Kuhls, was completely surrounded by the enemy and fighting bravely. He is without doubt a prisoner, if not killed or wounded. Captain G. A. Stone, Second Massachusetts Cavalry, who was also with the party, is reported badly wounded, in the house of Mr. Thomas Taylor, near Centreville, and a party has been sent to bring him into camp. Colonel Lowell has not been heard from since he started, but is expected in to-night. Nothing has been heard of any party of rebels from the direction of either Thoroughfare Gap or Manassas, though scouting parties have been sent out continually, who would be likely to obtain information of an advance from those directions.

Very respectfully, your obedient servant,

H. M. LAZELLE,

Colonel Sixteenth New York Vol. Cav., Commanding Brigadier

Lieutenant Colonel JOSEPH H. TAYLOR,

Assistant Adjutant-General and Chief of Staff.