mud, a thick stratum of grass was laid and thoroughly trampled down; on this were placed two thicknesses of tarpaulin, filling the entire space, and on these about 15 inches of well-rammed sand; over these are three thicknesses of 3-inch yellow pine plank. The lower two courses rest on one another and the sand, and the ends on the welting strip spiked inside the sheet piling; the third, or top layer, includes the heads of the sheet piling, and rests on the course below it and the heads of the piles. The two lower tiers are diagonal to, and the top course is in the line of, fire. The lower courses cross one another.

97. Under the logs of the foundation of the parapet, upon the mud, and transversely to the direction of the lower tier, quantities of grass, cut in the swamp, are laid, and upon this two thicknesses of heavy canvas tarpaulins. The interstices between the grillage logs are filled with sand and the bags broken in transportation, and around the logs are piled other broken bags in the transportation, and around the logs are piled other broken bags in the nature of a ramp, to give additional wight on the surface, or near the surface, of the surrounding marsh, to keep it from rising unequally if the battery should sink.

98. On the left of the battery a road was made, leading from the gorge around the left flank to the edge of the river. It is formed of longs and planks traversal bedded in the mud, and has a layer of sand-bags over it. The guns and gun carriage, and system of timber work, forming the authorized gun platform, were taken over this road from boats brought to the landing place, at the end, at high water.

99. During the time battery was in course of construction, all the material was carried by boats, and many of the details-all, at first-went to the work and returned in this way; but, as soon as practicable, a plank walk was built from the angel of the road between the left center breaching batteries and Black Island to the Marsh Battery, and after the night of the 12th of August most of the work-men were marched over it. A platform was built near the intersection, on which the reserve of the covering party were place, by order of General Terry.

100. To secure the working parties against surprise, picket-boats were kept in the stream leading to James Island and Charleston

Harbor, and two naval boats with bow howitzers were also stationed by the admiral in the same water.

101. During the night of the 12th of August, a boom of heavy round pine logs, chained together, was put across the river, at the point indicated on the map, and securely anchored to the banks, to obstruct the passage of boats that might attempt to come up from Charleston Harbor.

102. the work was done under the direction of Lieutenant Charles B. Parons, Volunteer Engineers.

103. In the construction of the Marsh Battery, I was assisted on the ground by Captain Charles P. McKenna, Lieutenant Nathaniel M. Edwards, and Lieutenant Charles B. Parsons, Volunteer Engineers.

104. The gun in this battery is a 200-pounder Parrott rifle, upon an iron carriage, with the authorized wooden platform resting on the gun-deck. It is manned by a detachment of Colonel Plaisted's Eleventh Maine Regiment, commanded by Lieutenant Sellmer.

105. In the construction o the Marsh Battery, the following labor and materials were expended:

106. Thirteen thousand sand-bags; 123 pieces, 15 to 18 inch diameter, yellow pine timber, 45 to 55 feet long; 5,000 feet 1-inch boards; 8