HEADQUARTERS CAVALRY DIVISION,
Camp near Knoxville, Md., October 15, 1862-6.30 p.m.

General R. B. MARCY, Chief of Staff:

GENERAL: Your dispatch of this date received. I will send Lieutenant-Colonel Buchanan, whit the Third Indiana Cavalry (say, 350 men), to report to General Hancock by daylight to-morrow morning. Colonel Farnsworth is on sick leave, and Colonel Buchanan is the next senior present for duty. The Indiana cavalry horses are in the best condition of any in my command.

Very respectfully,

A. PLEASONTON,

Brigadier-General, Commanding.

HEADQUARTERS ARMY OF THE POTOMAC,
October 15, 1862-7 p.m.

General GEORGE STONEMAN, Poolesville, Md.:

General Halleck telegraphs to-day that there are additional indications that the enemy is preparing for another raid or a more general movement, and that the impression is that he will attempt to cross the Potomac below the Point of Rocks. The commanding general directs that you have the river upon your line well watched and guarded. Our signal officer on Maryland Heights, with a powerful telescope, saw what he took to be the camp of about a division of troops a little east of Leesburg this afternoon.

R. B. MARCY,

Chief of Staff.

SPECIAL ORDERS,
HEADQUARTERS ARMY OF THE POTOMAC,

Numbers 282.
Camp near Knoxville, Md., October 15, 1862.

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VI. Major General H. W. Slocum, U. S. Volunteers, is assigned to the command of the Twelfth Corps, and will enter upon his duties accordingly, with as little delay as practicable; and Brigadier General J. Newton is assigned to the command of the division now under Major-General Slocum.

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By command of Major-General McClellan:

S. WILLIAMS,

Assistant Adjutant-General.

WASHINGTON, October 15, 1862.

Major-General BANKS, Commanding, &c.,:

GENERAL: I have but a single suggestion to make upon the report of dispositions sent in last night. I am told that there are several fords between High [Great] Falls and Seneca Creek. If so, they should be well guarded with artillery and infantry, if you can spare the forces.

Very respectfully,

H. W. HALLECK,

General-in-Chief.