On the 3rd the following orders were given for the movements of the 4th:

Porter's and Hamilton's division and Awell's cavalry, of the Third Corps, and Sedgwick's division, of the Second Corps, under Brigadier-General Heintzelman, commanding Third Corps, will move to-morrow in the following order: Porter's division, with Averell's cavalry, at 6 a.m., over the New Market and New Bridges to Big Bethel and Howard's Bridge. This division will send toward to the batteries where the Ship Point road intersects the main Yorktown road a sufficient force to hold that point and cut off garrison of the Ship Point batteries. The whole division may be used for this purpose if necessary, and if possible the batteries should be occupied by our troops to-morrow. The portion of the division not necessary for this purpose will encamp at Howard's Bridge.

Hamilton's division will march at 7 a.m. by the New Bridge road to Big Bethel, and will encamp on Howard's Creek.

Sedgwick's division will march at 8 a.m. by the New Market Bridge, taking the direct road to Big Bethel, and will also enemy at Howard's Bridge.

Brigadier-General Keyes, commanding Fourth Corps, will move with Smith's and Couch's divisions at 6 a.m. (Smith's division in advance) by the James River road. The Fifth Regular Cavalry, temporarily assigned to this corps, will move with Smith's divisions, which will encamp at Young's Mill, throwing forward at least one brigade to the road from Big Bethel to Warwick. Couch's division will encamp at Fisher's Creek.

The reserve cavalry, artillery, and infantry will move at 8.30 a.m. by the New Market Bridge, to Big Bethel, where it will encamp. On the march it will keep in rear of Sedgwick's division.

The following is an extract from the order issued on the 4th for the march of the 5th:

The following movements of the army will be carried out to-morrow (5th):

General Keyes will move forward Smith's division at 6 a.m., via Warwick Court-House and the road leading near the old ship-yard, to the "Half-way House," on the Yorktown and Williamsburg road.

General Couch's division will march at 6 a.m. to close up on General Smith's division at the "Half-way House."

General Keyes' command will occupy and hold the narrow dividing ridge near the "Half-way House," so as to prevent the escape of hate garrison at Yorktown by land and prevent re-enforcements being thrown it.

General Heintzelman will move forward General Porter's two rear brigades at 6 a.m. upon the advance guard, when the entire division will advance to a point about 2 3/4 miles from Yorktown, where the road turns abruptly to the north and where a road comes in from Warwick Court-House.

General Hamilton's division will move at 6 a.m., and follow General Porter's division, camping as near it as possible.

General Sedgwick's division will march at 5 a.m. as far as the Warwick road, which enters the main Yorktown road near Dr. Powers' house and will await further orders.

The reserve will march at 6 a.m. upon the main Yorktwon road, halting for further order at Dr. Powers' house, the infantry leading, the artillery following next, and the cavalry in rear.

General Sedgwick's division will for the present act with the reserve, and he will receive orders from headquarters.

In giving these orders of march for the 4th and 5th it was expected that there would be no serious opposition at Big Bethel, and that the advance of the Third Corps beyond that point would force the enemy to evacuate the works at Young's Mill, while our possession of the latter would make it necessary for him to abandon those at Howard's Bridge, and the advance thence on Yorktown would place Ship Point in our possession, together with its garrison, unless they abandoned it promptly. The result answered the expectation.

During the afternoon of the 4th General Keyes obtained information of the presence of some 5,000 to 8,000 of the enemy in a strong position at Lee's Mill. The nature of that position in relation to the Warwick not being at that time understood, I instructed General Keyes to attack and carry this position upon coming in front of it.