Parties coming out from Weston should be very careful; they are watching for messengers, &c.

Very respectfully, yours, &c.,

C. J. HARRISON,

Captain, Commanding Detachment Sixth [West] Va. Infty.

Captain OVER,

Acting Assistant Adjutant-General.

AUGUST 26-29, 1863.- Expedition from Williamsburg to Bottom's Bridge, Va., and Skirmishes.

REPORTS.

Numbers 1.- Colonel Benjamin R. Onderdonk, First New York Mounted Rifles, commanding expedition.

Numbers 2.- Lieutenant Colonel William Lewis, Fifth Pennsylvania Cavalry.

Numbers 1. Report of Colonel Benjamin F. Onderdonk, First New York Mounted Rifles, commanding expedition.

HEADQUARTERS CAVALRY BRIGADE,
Nea Williamsburg, Va., August 30, 1863.

CAPTAIN: Pursuit to instructions contained in Special Orders, Numbers 65, headquarters United States forces, Yorktown, Va., August 25, 1863, I left camp at 1 o'clock p. m., 26th instant, with 650 men and two howitzers of the First New York Mounted Rifles, and 254 men of the Fifth Pennsylvania Cavalry. I marched to Twelve-Mile Ordinary on the Richmond road, halted and fed. Being unacquainted with the country I deemed it best to remain there during the night. From this place I communicated by courier with headquarters stating progress, and also that it would not be safe to communicate again till my return. August 27, at 5 a. m., took up the line of march, halted at 8 o'clock for breakfast and fed at Ball's farm, a distance of 10 miles from bivouac, having encountered 2 pickets, the last at Barhamsville. Neither of them were captured.

On leaving this bivouac the First Mounted Rifles marched in advance. At Slatersville a picket of 8 mounted men was discovered. The advance guard gave chase, captured 2, and killed 1 after a pursuit of nearly 2 miles. At New Kent Court-House another picket was found, 1 of whom was captured, the balance escaping in the dense wood in the direction of Tunstall's Station. I halted at the court-house at 12 to rest the horses after the run, also for feed and dinner.

At this place citizen O. M. Chandler was arrested for volunteering to Major Wheelan, commanding advance guard, "the men you are after went that way," signifying the left road, when he knew they had taken the right, thus assisting the enemy, and opposing an officer of the United States in the performance of his duty.

At 2.30 p. m. left camp. At Baltimore Store found a picket of the enemy, but they were posted on a hill, had early notice of our approach, and escaped. Here arrested at Mr. Elmore, an employee of the so-called Confederate Government at Richmond. He was attempting to escape into the woods when taken.

Thence to Baltimore Cross-Roads, sending a detachment of the