I deem it of the utmost importance to make this statement to you for the information of the War and Navy Departments and the President, although the information may already be in their possession.

My cavalry drove in the enemy's pickets last evening, but the advance of their pickets and their increasing force admonishes me of the necessity of arranging my troops on the second line for defense, from which I have advanced them after the naval action, to be ready to take advantage of the effect of that achievement, and at the same time to cover, if possible, the movement of troops from here to Suffolk. They will resume their places to-day, presenting, however, the same line of pickets to the enemy and holding the front line by cavalry and light infantry, with orders to fall back on the second line in case of an advance.

I would recommend that not a moment by lost in again bringing out the Virginia, as I learn from my spies that their officers say the Virginia is much injured and that they have no apprehension from her for the present. I presume that they will advance as soon as possible in the hope that she will not be ready, and the Ericsson once up the river, she cannot follow. Should the Ericsson attack our batteries on James River, the guns on ship carriages will be withdrawn from the effects of the fire and all the other guns and men will be protected as much as possible.

I am, sir, very respectfully, your obedient servant,

J. BANKHEAD MAGRUDER,

Major-General, Commanding.

RICHMOND, VA., March 13, 1862.

Major General J. B. MAGRUDER,

Commanding, &c., Yorktown, Va.:

GENERAL: I have the honor to acknowledge your letter of the 12th instant, reporting the result of a reconnaissance made by your orders of the condition of the enemy at Newport News and your proposed movements in the event of an advance by him up the left bank of the river. As regards the steamer Virginia, the Secretary of the Navy informs me that she went into the dock upon her arrival at Norfolk, with orders that neither labor nor expense should be spared upon her repair. It is hoped that she will be out at an early day.

I am, &c.,

R. E. LEE,

General, Commanding.

YORKTOWN, March 13, 1862.

(Received March 14, 1862.)

General S. COOPER,

Adjutant and Inspector General:

To-day the enemy drove in our pickets 4 miles below Young's Mill. Troops are being again landed at Newport News from the Baltimore boat. Please order at once to Williamsburg by the James River boats the regiment which the Secretary of War said he would send. when will the Virginia be out? The disposition of my troops and the nature of my operations depend upon the answer to this question. Answer by telegraph.

J. BANKHEAD MAGRUDER,

Major-General, Commanding.