Excerpt from Reports of the Operations of the Army of Northern Virginia, Vol. 1 of 2: From June 1862, to and Including the Battle at Fredericksburg, Dec. 13, 1862 According to the general order of battle, a copy of which is an nexed, General Jackson was to march 'from Ashland On the 25th, in the direction of Slash Church, encamping for the night west of the Central railroad, and to advance at three, a. Degreesm on the 26th; and turn Beaver Dam. A. P. Hill was to cross the Chickahominy at Mesa dow Bridge, when Jackson's advance beyond that point should be known, and move directly upon.mechanicsville. As Soon as the Me'chanjcsville bridge should be uncovered, Longstreet and D. 'h. Hill. Were to cross the latter to proceed to the support of Jackson, and the former to that of A. P. Hill. The four commands were directed to sweep down the north side of the Chickahominy towards the yorkriver railroad, Jackson on the left and in advance, Long street nearest the river and in the rear. Huger and Magruder were ordered to hold their positions against any assault of the enemy, to observe his movements, and follow him closely should he retreat. General Stuart, with the cavalry, was thrown out on Jackson's left, to guard his flank, and give notice 'of the enemy's movements. Brig; sdier General Pendleton was directed to employ the reserve artillery. So as to resist any approach of the enemy towards Richmond, to superintend that portion offlt posted to aid in the Operations on the north bank, and hold the remainder ready for use when it might be required. In consequence of unavoidable delays, the whole of Gene ral Jackson's command did not arrive. At Ashland in time to enable him to reach the point designated on the 25th. His march'on the 26th was consequently longer than had been anticipated, and his pro; gress' being also retarded by the enemy, A. P. Hill did not begin his movement until three, P. M., when he crossed the river and advanced upon Mechanicsville. After a sharp conflict; he drove the enemy from h1s entrenchments, and forced him to take refuge in his works, on the left bank of Beaver Dam, about a mile distant. This position was a strong one, the banks of the creek in front being high and almost and the approach to it over open fields, comson being expected to pass Beaver 'dam above, and turn the enemy's right, a direct attack was not made by General Hill. -one of his regiments on the left of his line crossed the creek to communicate with Jackson, and remained until after dark, when it was withdrawn. Longstreet and D. H. Hill crossed the Mechanicsville bridge as soon as it was uncovered and could be repaired, but it whs late before they reached the north bank of the Chickahominy D. H. Hill's leading brigade, under Ripley, advanced to the support of the troops engaged, and at a late hour united with Pender's brigade, of A. P. Hill's divis ion, 'in an effort to turn the enemy's left, but the troops were unable, in the growing darkness, to overcome the obstructions, and after sustaining a destructive fire of musketry and artillery at short range, were withdrawn. The fire, was continued until about nine, P. M., When the engagement ceased Our troops retained the ground on the right bank, from which the enemy had been driven. Ripley was relieved at three, P. M., on the 27th, by two of Longstreet's brigades, which were subsequently reinforced. In expectation of Jackson's arrival on'the enemy's right, the battle was renewed at dawn, and continued with animation for about two hours, during which the passage of the creek was attempted, and our troops forced their way to'its banks, where their progress was arrested by the nature of the stream. They maintained their position, while preparations were being made to cross at another point nearer the Chickahominy. Be fore they were com'pleted, Jackson crossed Beaver Dam above and the enemy abandoned his entrenchments and retired rapidly down the river, destroying a great