HEADQUARTERS CENTER GRAND DIVISION,
Phillips House, December 13, 1862.

Brigadier General W. W. AVERELL,

Commanding Cavalry Brigade:

The major-general commanding directs that you dispatch a cavalry force in the direction of Hartwood, and beyond, should you deem it necessary, to patrol the roads and observe and prevent any movements of the enemy's cavalry in that direction. Our right flank is but weakly covered, and the major-general commanding the Army of the Potomac desires to receive timely notice of any approach from that direction. The general desires that your pickets may be instructed to keep well on the alert, night and day. Please instruct your cavalry force to return to-night, in case they should make no discovery to require their longer absence. Let the officer in charge be instructed to report as often as he has anything of importance to communicate.

Very respectfully, &c.,

JOS. DICKINSON,

Assistant Adjutant-General.

HEADQUARTERS CENTER GRAND DIVISION,
Phillips House, December 13, 1862.

Brigadier General W. W. AVERELL,

Commanding Cavalry Brigade:

The major-general commanding directs me to request that you dispatch no additional force in the direction of Hartwood, as ordered to-day, until further orders. General Pleasonton, with a heavy force, will move in that direction, to cross at the United States Ford, if practicable, and move up in rear of the enemy, on the south side of the Rappahannock.

Very respectfully, &c.,

JOS. DICKINSON,

Assistant Adjutant-General.

HEADQUARTERS CENTER GRAND DIVISION,
Phillips House, December 13, 1862

Brigadier-General STONEMAN,

Commanding Third Corps:

GENERAL: I am directed by the major-general commanding the center grand division to inform you that it has just been reported to him that Birney's division was lost last night in marching to the point it was directed to bivouac. This appears so extraordinary and unnecessary, that the commanding general desires you will call on the brigadier-general in command of that division to report the circumstances under which it happened, and also his reasons for not having ascertained in advance of his march the route over which his troops were to pass. A battle may be lost by the omission of officers to use the means in their power to be informed of the line over which their commands are to move.

Very respectfully, your obedient servant,

JOS. DICKINSON,

Assistant Adjutant-General.

8 R R-VOL XXI