HEADQUARTERS ARMY OF THE POTOMAC, April 2, 1862.

ORDER OF MARCH.

Porter's and Hamilton's divisions, of the Third Army Corps, and Sedgewick's and Averell's cavalry, of the Second Army Corps, under Brigadier-General Heintzelman, will move on the 4th instant in the following order:

Porter's division, with Averell's cavalry, at 6 a.m., over the New Market and New Bridges, on both roads, to Big Bethel and Howard's Bridge. This division will send forward to the batteries where the road to Ship Point diverges from the main Yorktown road a force sufficient to occupy that point and cut off the garrison of Ship Point batteries. The remainder of the division will camp at Howard's Creek.

Hamilton's division will march at 7 a.m. by the road over the New Bridge to Big Bethel,and will camp as near as possible to Howard's Creek.

Sedgewick's division of the Fourth Corps, under Brigadier-General Keyes, will move on the 4th instant at 6 a.m. by the James River road.

Smith's division to Young's Mill, sending one brigade forward to the road from Big Bethel to Warwick.

Couch's division will camp at Fisher's Creek.

The reserve artillery and infantry will move at 9 o'clock on the 4th instant by the New Market Bridge and the direct road to Big Bethel, then taking the Warwick Court-House road, and camp in the vicinity of the junction of this road with the Young's Mill road.

By command of Major-General McClellan:

--- ----,
Assistant Adjutant-General.

HAMPTON ROADS, April 3, 1862-12.15 a.m. (Received 10 a.m.)

Honorable E. M. STANTON:

Have seen Goldsborough, and feel sure that he will crush the Merrimac if she appears. Hope to move to-morrow. My only trouble is the scarcity of wagons, but I will overcome the difficulty in some way or other. We shall not get through without a hard battle, and perhaps more than one, but I am confident that we will win.

GEO. B. McCLELLAN,

Major-General, Commanding.

HAMPTON ROADS, April 3, 1862-12.20 a.m.

Honorable JOHN TUCKER,

Assistant Secretary of War:

We need many more tugs; please send ten more here at once. If you can procure promptly about six light-draught ferry-boats they would be of great use.

GEO. B. McCLELLAN,

Major-General, Commanding.