follows: Five regiments, First Brigade, Second Division, 1,900; Independent Battalion, 500; and there are 250 negro laborers. From this force must necessarily be deducted the old and new guards, 250 men, and the regiment detailed to man the guns, 370 men, leaving a total of 2,000 men to work, if unmolested by the enemy; and it is estimated that it will take this force thirty days to accomplish the work of destroying the approaches and restoring the slopes and ditches of the work itself. These estimates are independent of the work at Gloucester Point, where two regiments of the First Brigade are stationed and where the picket and fatigue duty is sufficient to occupy their attention.

Of what is necessary.

The plan of the board of engineers, a copy of which is in possession of Major-General Peck, a member of this board, and which has been approved by General McClellan and herewith submitted, contains, in the opinion of the board, all the suggestions necessary to place Yorktown in a state of defense. But in the opinion of the board the force now left here is wholly inadequate to accomplish this work within the time when the enemy is likely to attack this work, if it is attacked at all; and of the armament suggested in that plan of defense, none has been sent.

The board recommend that armament be at once sent, and urgently recommend that an ordnance officer be sent to mount that armament and direct the readjustment of the pieces now here.

The board is of the opinion that when the work is in a state of defense contemplated by the engineers, the garrison necessary to hold it and the approaches should consist of one regiment of cavalry, one regiment of artillery, and 4,000 infantry, if of old troops; if of new levies, from 6,000 to 8,000 infantry.

There is at present but one gunboat at this place. In the opinion of the board two more are necessary-one on each of the flanks of the work, and he third to pass up and down the river and break up the trade between Richmond and the rich counties of Gloucester and Matthews, on the eastern side of the river.

In this connection it is proper to state that the height and abruptness of the bank of the river at Yorktown will diminish the aid that might otherwise be expected from their co-operation in the defense of the work.

There is with the garrison at Gloucester Point a field battery of four pieces, and in this fort two field batteries of four guns each, but it is not known whether the two batteries at this place are a part of the garrison.

JOHN J. PECK,

Major-General.

W. H. EMORY,

Brigadier-General.

JOHN C. DODGE, JR.,

Colonel Fifty-second Pennsylvania Volunteers.

HEADQUARTERS FOURTH CORPS,
Yorktown, September 3, 1862.

The proceedings of the board of which Major-General Peck is president are approved. The board is dissolved.

E. D. KEYES,

Major-General, Commanding Fourth Corps.