HDQRS. DEPT. OF SOUTH CAROLINA AND GEORGIA, Charleston, S. C., November 1, 1862.

General S. COOPER,
Adjutant and Inspector General C. S. A., Richmond, Va.:

GENERAL: As reported in my indorsement, dated October 19, 1862, on a communication of Captain McCrady's, having become satisfied that the defenses of Savannah demanded my immediate attention, I repaired to that point on the 19th and remained there until the 30th ut. Meantime having made a careful examination of the entire works constructed or under construction, the following report is now submitted-not as an unnecessary criticism of what has been done or planned, but for the information of the War Department, and I may add that I submit this paper rather as an ex-engineer officer than as the commanding general of the department.

The system adopted for the defense of Savannah may be divided into three lines.

1st. The defense of the Savannah River.

2nd. The line of outworks covering the approaches to the city.

3rd. An interior line of works around the place. The first line consists of the pile and crib work constructed at the northern extremity of Elba Island, about 4 miles below Savannah and from 1 1/8 to 1 1/4 miles below Fort Jackson; of batteries Lee, Lawton, and the naval battery; Fort Boggs and Hutchinson Island Battery, about 1 1/4 miles below the city, and of Bay Battery, immediately at the lower extremity of the town. Fort Boggs, forming also a part of the interior line of defense against a land attack, has nine guns bearing on the river and five on the land approaches. The works of this line have a total of forty-seven guns and eight 10-inch mortars defending the river approach, but fifteen of which, however, are of heavy calibers; that is, 42-pounders and 8 and 10 inch columbiads; and of these it should be stated only thirteen guns and five mortars bear on the obstructions. In addition, the battery at Carston's Bluff, quite 2 miles from the obstructions, has two 8-inch columbiads bearing on them at that long range.

From the foregoing it will be apparent that the obstructions are too far removed from the works for their defense to be adequately protected by the small number of heavy guns bearing upon them, especially in view of the fact that the enemy's iron-clads of a certainty will be able at night or in a fog to work deliberately at their destruction.

The second line of works will now be considered, and which is made up as follows:

1st. Of a six-gun battery, of two 8-inch columbiads and four 32-pounders, at Carston's Bluff, on the Saint Augustine River, through which 15 feet of water can be carried 4 miles from Savannah.

2nd. Of a twelve-gun battery, of two 8-inch columbiads, two 42-pounders, seven 32-pounders, and one 24-pounder rifled gun, at Thunderbolt, on the Wassaw River, some 6 miles from the city.

3rd. Of an eight-gun battery, of two 42-pounders, five 32-pounders, and one rifled 12-pounder, at Beaulieu, on Vernon River, some 12 miles distant from Savannah, and to which 17 feet of water can be carried.

4th. Of a seven-gun battery, of one 8-inch columbiad, one 42-pounder, and five 32-pounders, at Genesis Point, on the Great Ogeechee River, about 25 miles from the city, and to which place 20 feet of water can be carried. But besides the approaches thus defended there are two other important landing places and routes of approach to Savannah which I find have been left nearly unfortified, to wit, the Isle of Hope