The rebels have built a very strong battery on Sewell's Point, at the entrance of Elizabeth River, about four miles from this post, and about two and one-half miles from the Ripraps, or Fort Calhoun, and supported in the rear, at the distance of about a mile across Tanner's Creek, by the rebel forces fathered about there, amounting, as nearly as I can ascertain, to some 3,000 or 4,000 men, it being understood from the attack of the Monticello on Sunday last that I intended to menace Norfolk in that direction. Of course I had not at my disposal any force sufficient to make such an attack and carry this battery with any hope of holding possession of it should it be taken. I had determined, however, upon consultation wit Commodore Stringham, to engage the battery with the naval force, and to endeavor, under the cover of their fire, to land and at least destroy the guns and works, and such plan was arranged for this morning; but yesterday Commodore Stringham received orders from the Navy Department to sail at once for Charleston, so that our expedition was disorganized. As we had no sufficient force to make such an attack-in the absence of the flag-ship Minnesota and her guns at long range-as would give the movements that assurance of success which I understand you desire should seem to attend our operations, it has been abandoned. I have, however, directed Colonel De Russy to prepare to put some guns of long range upon the Ripraps, so as to prevent any further approach towards us from Sewell's Point or Willoughby's Spit.

In this connection I beg leave to suggest to the Lieutenant-General the necessity in coast operations for say fifty surf-boats, of such construction as he caused to be prepared for the landing at Vera Cruz, the adaptation and efficiency of which have passed into history. May I respectfully request and urge that such a flotilla be furnished for coast operations.

I have learned that the enemy are about to fortify a point at Newport News, about eleven miles from this place, at the mouth of the James River, and on the northerly side of it. They have already a battery at Pig Point, on the southerly and opposite side of the river, which commands the Nansemond River. I think it of the last importance that we should occupy Newport News, and I am now organizing an expedition consisting of two regiments for that purpose, unless I find unexpected obstacles. I purpose this afternoon, in the steamer Yankee, to make a personal reconnaissance of that point, and at once to occupy the same with that amount of force, intending to intrench there for the purpose of being in possession and command of the entrance to the James River myself, and from that position, by the aid of the naval force, to be in condition to threaten Craney Island and the approaches of Norfolk, and also to hold one of the approaches to Richmond. By a march of nine miles, at farthest, I can support the post at Newport News; by the sea, in two hours, I can afford it relief. There is water enough to permit the approach of the largest sized vessels-indeed the Lieutenant-General will recollect that Newport New Point was once counted upon as a naval depot instead of Norfolk.

Trusting that these dispositions and movements will meet the approval of the Lieutenant-General, and begging pardon for the detailed length of this dispatch, I have the honor to be, most respectfully, your obedient servant,

BENJ. F. BUTLER,

Major-General, Commanding.