men and the capture of 30 men and 40 horses. A force of 100 men sent in pursuit returned this evening. The pursuit was kept up as long as there was any hope of overtaking the party, and until the horses were broken down. Three prisoners captured from Mosby.

D. McM. GREGG,

Brigadier-General of Volunteers.

Captain PARSONS,

Acting Assistant Adjutant-General, Cavalry Corps.

[Indorsement.]

HEADQUARTERS ARMY OF THE POTOMAC,
January 8, 1864.

Respectfully, returned to the commanding officer of the Cavalry Corps.

The commanding general desires an explanation of the delay in forwarding this intelligence, he having been unofficially advised of the circumstances last evening. A thorough investigation will at once be made into the affair, and report sent to these headquarters. It would seem that some one has been grossly derelict in duty.

By command of Major-General Meade:

S. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS SECOND CAVALRY DIVISION.

January 9, 1864.

CAPTAIN: I have the honor to report that a full investigation has been had of the circumstances of the attack upon and capture of the picket reserve of the Third Pennsylvania Cavalry on the morning of the 7th.

The attack was made about 4. 30 and by a force of the enemy estimated at about 50. At the hour it was very dark, and the wind was blowing violently. The attack upon the reserve was made from the rear, the enemy having gained the rear by passing through the picket-line (very probably in very small detachments), at a gap which should not have existed, and which was occasioned by the removal of a vedette from a point previously occupied. The responsibility of the removal of this vedette rests upon Lieutenant Warren, Third Pennsylvania Cavalry. This officer asserts that he acted by order of the brigade officer of the day. The brigade officer of the day denies having given the order for the removal of the vedette. The attack from the rear was unexpected and so sudden that the resistance offered was confused and ineffective. The officer in command was severely wounded, as were also 6 of his men. The entire loss on the occasion was 18 enlisted men captured, and 43 horses with equipments.

The reports furnished and examinations made convince me that the officer in command of the reserve is responsible for the disaster, which resulted from inattention and gross neglect of duty. The officers and enlisted men responsible will be brought to trial.

The intelligence of the affair was not at once communicated because of a force of 100 men having been sent in pursuit, which was confidently expected to overtake the enemy a short distance from Warrenton. It was desired to send with the report of disgraceful