HDQRS. CAVALRY CORPS, ARMY OF THE POTOMAC, December 11, 1863.

Brigadier General S. WILLIAMS,
Asst. Adjt. General, Army of the Potomac:

GENERAL: I would respectfully call the attention of the major-general commanding the army to the necessity of keeping up the strength of the Cavalry Corps, to enable it to perform the duties assigned it, more especially in connection with the extensive picket line it is habitually maintaining.

The casualties of the service are very severe upon this arm, and more recently it is being weakened by whole regiments leaving the army for purposes of re-enlistment and re-organization.

In view of this latter fact, I would respectfully suggest that the considerable number of new cavalry regiments now in depot at Washington might properly be drawn on, from time to time, to supply the place of those going away.

I have the honor to be, your obedient servant,

A. PLEASONTON,

Major-General.

HDQRS. CAVALRY CORPS, ARMY OF THE POTOMAC, December 11, 1863.

Major-General HUMPHREYS,
Chief of Staff, Army of the Potomac:

GENERAL: In consequence of the difficulty of tranasacting the current business of the Second Division, with one brigade at Warrenton and one east of Bealeton, as well as the necessity of having a sufficient cavalry force on our right flank, I respectfully suggest that the entire Second Division take post at Warrenton, and that the Third Division (Custer's) be posted on the left, between Bealeton and Morrisville. The First Division (Merritt's) has three on the left, while the other two would be sufficient for the front and right, with some assistance from the infantry, by having the infantry picket lines on the right and left connect with the cavalry, at the same time posting a brigade of infantry in Culpeper, to relieve the cavalry from looking after that place.

Unless plan of this kind is adopted, the very severe service which the cavalry is now called upon to perform on picket will seriously impair the efficiency of that arm during the coming winter. I may also state that the First Division is nearly as strong as both the Second and Third.

I am, very respectfully, your obedient servant,

A. PLEASONTON,

Major-General, Cavalry.

WAR DEPARTMENT, Washington, December 11, 1863-1.40 p.m.

Brigadier-General KELLEY,

Cumberland, Md.:

According to the latest advices Longstreet was at Morristown, East Tennessee, moving up the valley. Troops collected at Abingdon