Companies H, A, F, and G were on duty at the bridges. At the time of my arrival troops were crossing the three bridges.

At 3 a.m., the 16th instant, I ordered Companies E and K to commence dismantling the first bridge, which was done in about an hour; and as troops were still crossing the two remaining bridges, they were not disturbed until after daylight.

Immediately upon the passage of all the troops which were to cross at this point; the work of dismantling the middle bridge was commenced by Companies E and K, Companies H, A, G, and F assisting in loading cheeses, balks, &c. As soon as the bridge was completely dismantled, the boats were sent up the river, with crews from the different companies, but were soon brought back to their original position, Companies E and K remaining at the lower bridge opposite Fredericksburg and aiding to bring it to this side of the river.

Soon after daylight, Companies A, G, and H were relieved by Companies B, C, and I. The boats were unloaded, drawn out upon the bottom land, loaded on the wagons, and, as fast as teams could be procured, drawn away. The work of getting the boats and material in a safe place drawn away. The work of getting the boats and material in a safe place was continued until about 2 p.m. without interruption from the enemy, when, the batteries which had been placed on the hill above to protect us having been withdrawn, we were fired upon by a party of the enemy stationed in the houses and barns opposite. Our men and a detachment of the Seventy-seventh New York (who were on the ground) returned the fire. My men continued the work until 3 p.m., when all the property having been moved to a place of safety, we returned to camp.

Very respectfully, your obedient servant,

J. A. MAGRUDER,

Major, Commanding.

General D. P. WOODBURY,

Commanding Engineer Brigade.

Numbers 20. Reports of Major Ira Spaulding, Fiftieth New York Engineers.

WHITE OAK CHURCH, VA.,

December 12, 1862.

GENERAL: I have the honor to report that, in compliance with your orders, I moved three pontoon bridge trains to the Rappahannock on the night of the 10th instant, and at about 3 o'clock on the morning of the 11th we commenced laying the three bridges at the points designated opposite Fredericksburg, one being located opposite the docks, near the lower end of the town, and two at the rope ferry, about opposite the center of the town. The lower bridge was under the immediate superintendence of Captain McDonald, and the two upper bridges under Captains Brainerd and Ford, respectively.

At about 6 a.m., when one of the upper bridges and the lower bridge were two-thirds completed, and the other about one-fourth built, the enemy opened a galling fire upon us at the upper bridges, from the houses near the shore and from behind walls and fences, killing 1 captain and 2 men, and wounding several others. One bridge had approached so near the south shore that the men at work upon it were within 80 yards of the enemy, who were under cover, while the infantry supporting us on the flanks were at long range, and could do little