There are several points along the beach north of Fort Fisher where field guns are put in position, or can be to protect blockade runners. Smith's Island was entirely unoccupied until within two or three months; a few regiments thrown upon it by us would have led to the perfect closing of the blockade.

The fact that Cape Fear is undefended as yet, and that the only shelter for vessels is to be found directly under it, seems to pint out the only method, without the employment of a large force, by which any decided effect can be produced upon blockade-running. A few thousand men, landed upon Cape Fear at night, would certainly surprise the fort at Bald Point, particularly if they could be landed before the completion of that work. Should Bald Bluff not be fortified meanwhile, its possession alone would involve the fall of the fort, and if it be fortified a line of investment could be drawn around both, from the light-house to the sea beach. A few heavy rifles at the light-house would close the river. A gun or two on a point or spit farther north would forbid vessels lying at or near Smithville, and the Light-House Battery would prevent access to the fort on Bald Point, which should consequently bee say of conquest. The possession of this island would greatly facilitate any operations on Oak Island against Fort Caswell, but it is believed that the moral effect of the possession of Smith's Island and a few guns opposite Caswell would effectually prevent blockade-running by this entrance.

Of course such a landing on Smith's Island must be immediately followed by a movement up the beach and the occupation of Zeek's Island. Should this fail, the establishment of a few rifles at a point nearly 1 mile south would, nevertheless, close New Inlet.

Whatever is done near Cape Fear toward the closing of the blockade must be done soon, as the advantages now offered of a quiet anchorage at and occupation of the cape itself must soon pass way, and all operations by any moderate force will be virtually impracticable.

Five or eight thousand men can easily accomplish this operation, and the nature of Smith's Island is such that, once in our power, 3,00 men should be able to hold it with perfect ease.

T. SEYMOUR,

Brigadier-General.

C. B. REESE,

Captain of Eng., Asst. and Consulting Eng., Dept.of the South.

(Sketch with original.)

[Indorsement.]

HEADQUARTERS DEPARTMENT OF THE SOUTH,
Folly Island, S. C., November 18, 1863.

Respectfully forwarded for the information of the General-in-

Chief. I do not consider that the possession of Smith's Island alone could effectively close Wilmington river to blockade-runners, especially light-draught ones. With Fort Caswell and Zeek's Point in our possession and a couple of monitors lying near them all the time, I think the blockade could be made perfect even without Bald Head Point. The outer blockade could not, of course, be entirely abandoned.

I am not fully aware of what the intention of the fleet is here, of what the admiral's plans are,further than that he is waiting the arrival of more monitors, not expected for more than one month to come.

Q. A. GILLMORE,

Major-General, Commanding.