HEADQUARTERS CAVALRY DIVISION,
Camp near Warrenton, Va., November 17, 1862.

GENERAL: I have the honor to submit the following report of the operations of this command from the crossing of the Potomac in the vicinity of Warrenton, Va., and the relinquishment of the command of the army by Major-General McClellan:

On the morning of October 26, I crossed the Potomac at Berlin, with the Second Cavalry Brigade and Pennington's horse battery, and took up a position in front of Purcellville, on the 27th, having occupied Hillsborough with two squadrons of the Sixth Cavalry. After some skirmishing with the rebels, and having driven them out of Purcellville, they were followed up by Colonel davis, with the Eighth New York Cavalry, as far as Snicker's Gap, at which point they opened with shell and showed themselves in strong force.

From this time until November 1 the brigade was occupied in scouting the country to Leesburg, Aldie, Middleburg, Philomont, and in gaining information of the enemy's movements.

On November 1, the command moved forward and occupied Philomont, several hundred of Stuart's cavalry leaving about the time we entered. colonel Gregg, with the eighth Pennsylvania and Third Indiana Cavalry, pursued this cavalry and drove it very handsomely from some woods it attempted to hold, but, the enemy bringing up his artillery, no farther advance was made, except to silence the rebel guns by the fire of Pennington's battery.

The rebels left 5 dead on the field. Our loss was 1 killed and 1 officer and 13 men wounded.

On November 2, my advance came up with the enemy at Union, they had some infantry supporting their guns, and very soon some sharp fighting began, which resulted in the blowing up of one of their caissons, by which a number of their men were killed, and their retreat for several miles on the road to Upperville. [Sic.]

Lieutenant-Colonel Hofman, with a small brigade of infantry and a battery, reported to me for duty this morning from Doubleday's division.

The fighting did not cease until after dark, the rebels giving way at every point. Their loss must have been considerable. One of their officers was left dead on the field, and 10 wounded fell into our hands,besides a number of prisoners. My loss in my own brigade was 1 man killed and 26 wounded. The infantry brigade lost 5 men killed and 30 wounded.

Several companies of the Eighth Pennsylvania Cavalry proceeded to Bloomfield to-day and captured a number of rebel horses, arms, equipments, &c., and released Major O'Neill, of General Meagher's staff, before the rebels had paroled him; in fact, they ran away so quickly as to leave several hundred dollars of their paper money behind.

On November 3, Brigadier-General Averell, having reported for duty with the First Cavalry Brigade and Tidball's battery, was given the advance, and the infantry brigade and Second Cavalry brigade moved to the left. The infantry brigade and Second Cavalry Brigade soon came up with the enemy, and drove them on the road to Upperville. Averell soon joined, and the whole command moved forward and took possession of Upperville, driving the enemy through the town toward Ashby's Gap, as well as toward Piedmont. General Averell, with his brigade, moved after the column toward Piedmont, and the Second