of a naval force. This would certainly be easily from us as regards Mud River, as the enemy's gunboats could sweep it without coming within range of Venus Point battery. Moreover, if any advance movement should meet with disaster, and we should be under the necessity of falling back with the Venus Point guns, it would be next to impossible to take them off via Mud or Wright Rivers through their mounts. The causeway can be constructed 9 feet wide in one week by hurrying the work.

I am still of the opinion that Mud River can be deepened very much by running a side-wheel steamer up and down the stream. The bottom is very soft and the tide very strong. The guns have not been put in position at Wall's Cut.

Captain Hamilton writes on this matter:

The Unadilla and Pembina are both within the Cut, that is, this side of it, the former having left her advanced position.

Captain Hamilton's suggestion to tow the Keating down guns in working order on her deck, I cordially indorse, provided Captain Ridgers will take charge of her in the absence of any towing facilities of our own.

I shall return to Hilton Head to-morrow morning in the Mayflower. She will discharge here early in the morning, having just arrived from the Windfield Scott. I shall get set my force at work cutting stuff for the causeway to-morrow morning in anticipation of your approval of this project.

Very respectfully, your obedient servant,

Q. A. GILLMORE,

Brigadier-General and Chief Engineer.

[Inclosure Numbers 7.]

Memorandum by Lieutenant O'Rorke.

Left Daufuskie Island at 4.30 p. m. on 29th; left Unadilla 5.30 p. m. After passing south end Jones Island starred due west and landed about 100 yards north of the beacon on Long Island; beacon is about one-half way from one end to the other. Found a soil of dry brown clay, with a substratum of black mold; surface of ground about 2 1/2 feet above high water. Best ground and best position, as far as could be determined in the dark, about 100 yards south of the north point of island. Next rower carefully up the river to Elba Island; has some difficulty in fighting it in consequence of inaccuracy of map. Finally rowed up the north end of it, landing about six times and examining short and adjacent ground. Found shore impracticable for landing without cause waning out; ground above the upper half of island all a soft marsh, not practicable for batteries. Returned to a point just south of mouth of Mud River, arriving just before daylight. Hauled the boat ashore and crossed the island to the Georgia side; traveled about 1 mile north of the point at which we landed. Ground on Georgia side overflowed at high water for quite a distance. Tower at mouth of Saint Augustine Creek probably shot tower. Let the men sleep an hour; recrossed the Savannah, and arrived at 1 p. m. of 30th.

[Inclosure Numbers 8.]

HDQRS. EXPEDITIONARY CORPS, Feb. 4, 1862.

General GILLMORE, Chief Engineer, Commanding:

GENERAL: Yours is received. I am just from the Wabash. Captain