wide, anchored across the main channel of the bayou by a cable and chain on the southern end and braced against a tree on the northern. Ties of timber, trimmed to 6 or 8 inches thickness, are laid over the gunwales, upon which rest 8 by 12 stringpieces, supporting the planks. The next span toward either shore rests on a 12 by 12 timber, notched half into trees on either side, pinned and secured by chains. There are three more spans toward both shores, resting on trestles, each formed of four uprights, 8 inches square, secured at top and bottom to squared logs. The roadway is confined by heavy beams, pinned to the planks and string-pieces, and on the north end a wooden railway has been formed, which is, however, too smooth on the ascent to by any advantage.

The bridge is 362 feet long, 240 feet resting on trestles and immovable, the balance afloat. If the bayou should rise or fall more than 18 inches, the connection between the floating and fixed part would be insecure, and the ascent and descent almost impracticable. The roadway is not laid exactly along the center of the flat, but rather down stream, which causes a slight sideway slope. The flat has sagged considerably, rising at the middle; but whether this is an old defect or caused by overloading the ends, I cannot say, as I could net examine it very closely, the bridge being crowded by the passage of troops. As long as the bayou remains at its present stage, I think the bridge perfectly secure.

The bridge across Negro Bayou is 550 feet long, curved up stream, and rests on sixteen flats, mostly new, from 25 to 40 feet long and 12 feet wide, with landings on trestles on either side. Tho boats are anchored to a 2 1/2-inch line, stretched from shore to shore, and supported in the center by a tree. Some of the boats are fastened directly to the cable passing over their bows; others are connected with it by short ropes. The connection with both shores is effected in a manner similar to that of the Bayou Vidal bridge, including some ties resting in notches cut into trees.

Another bridge, 150 feet long, has been constructed across a slough between the two bayous. It rests on a center pier, formed of logs, placed crosswise, and on trestles on either side of the pier. The roadway is formed of split logs, and appears sufficiently firm.

Squads of pioneers are stationed at all three bridge to repair such damages as may occur. On account of the heavy rain and continual passage of troops and trains, I was unable to obtain more minute measurements.

I reported on the condition of the bridges to Major Hickenlooper, acting engineer on General McPherson's staff.

I have the honor to be, very respectfully, your obedient servant,

H. A. ULFFERS,

Assistant Engineer.

With these two bridges, both of which were very substantial, a good road was completed from Milliken's Bend to Perkins' plantation, 8 miles below New Carthage. After the failure of the Navy, with seven iron-clads, to silence the batteries at Grand Gulf on April 29, after five and a quarter hours' cannonading, it was determined to run the six transports by that place, and march the troops to a point below.

On April 25, in accordance with instructions of General Grant, accompanied by Assistant Engineer Rigby and one regiment of infantry, I landed just above the mouth of Big Black, and carefully examined the country up to the foot of Palmyra Island, for a practicable road to the highlands. The river bottoms throughout the entire distance, several miles wide, were overflowed from 4 to 10 feet deep near the hills, so that communication, except at Congo plantation, was entirely cut off.

This plantation, lying just south of and on the Big Bogasha, is probably 18 inches higher than the bottom above and below, and protected from the freshets by a levee, extending entirely around

it. It has a good road, just passable, running through it and the adjoining place to Cox's or Thompson's Ferry, over the Big black. The two rivers in this locality are only about 2 1/2 miles apart. The Mississippi was at that time about 3 feet below its highest mark for this season. There being no fixed plane of reference for high water, it is impossible to describe accurately at what stages this road could be used; but that part next the Big Black being unprotected by a levee, would have been entirely submerged by a slight rise in either river. The country north of the Bogasha was overflowed at the time reconnaissance, but the hills