NOVEMBER 12, 1861.-Reconnaissance to Pohick Church and the Occoquan River, Virginia.

REPORTS.

Numbers 1.-Brigadier General Samuel P. Heintzelman, U. S. Army, commanding division.

Numbers 2.-Brigadier General Israel B. Richardson, U. S. Army, commanding brigade.

Numbers 3.-Colonel Henry D. Terry, Fifth Michigan Infantry.

Numbers 4.-Colonel Samuel B. Hayman, Thirty-seventh New York Infantry.

Numbers 5.-Captain Frederick Hendrich, First New York Cavalry.

Numbers 6.-Colonel Hiram G. Berry, Fourth Maine Infantry.

Numbers 7.-Captain Henry B. Todd, First New York Cavalry.

Numbers 8.-Lieutenant John Ennis, First New York Cavalry.

Numbers 1. Report of Brigadier General Samuel P. Heintzelman, U. S. Army, commanding division.

HEADQUARTERS OF DIVISION,
Fort Lyon, November 13, 1861.

GENERAL: The enemy having made a demonstration a demonstration against our pickets on the 11th instant, I sent out two small parties of cavalry to reconnoiter. On their return I received a report that the rebels, with 400 cavalry and two regiments of infantry, were encamped near Pohick Church. Believing I could disperse them, I telegraphed to the commanding general, and was authorized to prepare an expedition.

On the 12th instant, at 3 a.m., General Richardson's brigade, with Company G of the Lincoln Cavalry [First New York], and Captain Thompson's and Captain Randolph's batteries of artillery, advanced upon Pohick Church by the Telegraph road, followed an hour later by General Jameson's brigade, and Company E, Lincoln Cavalry. The instructions I gave were for General Richardson to divide his brigade at Potter's house, just beyond Piney Run, he to follow the Telegraph road, and the other two regiments, with a battery and company of cavalry, to cross to Accotink, and reach Pohick Church by the Accotink and Pohick continuation of the Alexandria turnpike, so to time his march as to have both column reach the church at the same moment. General Jameson's brigade followed an hour later on the Telegraph road, as a reserve.

I left headquarters at daylight, and overtook the advance where they were halted, a short distance this side the church. We soon ascertained that the rebel cavalry had left, having encamped at the church the night before. We advanced and occupied the ground, and sent out parties on the different roads. The regiments under Colonel Hayman took the road to Colchester. There were no signs of the enemy having been recently in that vicinity, nor were there any indications of their occupying the opposite bank of the Occoquan at that point. Colonel Terry, who commanded the troops which followed the Telegraph road to Mrs. Violet's, learned that the enemy's pickets had left there was seen a small force of cavalry and infantry, evidently apprised of our advance. The cavalry pickets on the road towards Elzey's had also retreated very recently. Having ascertained these facts, the troops returned to their camp.