[Confidential.]

SEPTEMBER 1-8.35 p.m.

General GEORGE B. McCLELLAN, Washington:

The following has just been sent in by General Porter.

S. WILLIAMS,

Assistant Adjutant-General.

Official copy.

WM. P. MASON, JR.,

Captain and Aide-de-Camp.

[Received September 1-8.50 p.m.]

General McCLELLAN, near Alexandria, Va.:

Bayard reports the enemy pouring in on the Chantilly road, and my pickets that they are coming down the Little River turnpike. Twelve brass guns were seen, and infantry and cavalry. I can see the dust and flags; columns evidently moving directly north; evidently toward Leesburg. If you can, I hope you will protect the fords into Maryland, and guard the railroad to Baltimore. I think we will have a fight before night. The enemy are between us and Fairfax Court-House, and shelled our trains last night. We will fight, or they will avoid us and strike our rear first. We have been held on to thirty-six hours too long, and are bound to work our away to Alexandria. I only regret that we have not been distributed to forts, and to the fords over the Potomac into Maryland. God speed your operations, and enable you and others in authority to save our country!

Yours,

F. J. PORTER,

Brigadier [Major] General, Commanding.

Official copy.

WM. P. MASON, JR.,

Captain and Aide-de-Camp.

UNITED STATES MILITARY TELEGRAPH, War Department, August 30, 1862.

(Received, 3 p.m.)

Received in cipher.

No. 66.] HEADQUARTERS FIELD OF BATTLE,

Near Groveton, Va., August 30, 1862-5 a.m.

Major General H. W. HALLECK,

General-in-Chief, U. S. Army:

We fought a terrific battle here yesterday with the combined forces of the enemy, which lasted with continuous fury from daylight until after dark, by which time the enemy was driven from the field, which we now occupy. Our troops are too much exhausted yet to push matters, though I shall do so in the course of the morning, as soon as General Fitz John Porter comes up from Manassas. The enemy is still in our front, but badly used up. We have lost not less than 8,000 men