UPTON'S HILL, VA.,

September 4, 1862 - 2.30 a. m.

Major General GEORGE B. McCLELLAN:

Evidence accumulates that the main body of the rebels have gone in the direction of Leesburg.

J. D. COX,

Brigadier-General, Commanding.

UPTON'S HILL, VA.,

September 4, 1862 - 3.45 p. m.

General R. B. MARCY, Chief of Staff:

Some rebel cavalry, with horse artillery, are feeling the front of General Pleasonton's lines. I sent forward a regiment of infantry and section of artillery to support him in front of Falls Church. This section is all I have out of the forts.

J. D. COX,

Brigadier-General.

UPTON'S HILL, VA.,

September 4, 1862 - 5.40 p. m.

Colonel A. W. COLBURN,

Assistant Adjutant-General:

The rebel force was on the hill just above Pimmit Run, on Leesburg pike. they drove in General Pleasonton's pickets to that point. The movements appear to be a feint. I saw cavalry and two pieces of light artillery. Should not estimate the force large. General Pleasonton is supported by Patrick's brigade and one regiment of mine. General Patrick has a battery with them. I informed General Pleasonton that it was not regarded desirable to engage the enemy far in front of this position. He will keep some cavalry well forward and watch the movement. In answer to the general's question, Captain Barnes' company, Fourth New York Heavy Artillery, is in Fort Ramsay, and is strong enough to man all the heavy guns there. I think it very desirable to arm Fort Buffalo with, say, 20-pounder Parrotts. I have two 20-pounders and two 10-pounders in it now, but would like very much to have a battery of 20-pounders there besides. If furnished with horses they could be easily moved and protected.

J. D. COX,

Brigadier-General.

UPTON'S HILL, VA.,

September 4, 1862 - 6.45 p. m.

A. V. COLBURN,

Assistant Adjutant-General:

The firing upon General Pleasonton's command was from, possibly, three pieces of light artillery. The small-arm fighting was confirmed to the head of the enemy's column, deployed as skirmishers, with some dismounted men or infantry, it is not certain which. The pickets of Pleasonton's command, Eighth Illinois and Eighth Pennsylvania Cavalry, skirmished with them. We lost 2 men shot. The force of the enemy did not come beyond the edge of the woods, 1 1/2 or 2 miles above Falls Church, and no large numbers were actually seen. The reports sent by General Pleasonton were necessarily those brought in by his