HEADQUARTERS Fifteenth ARMY CORPS,
Camp at intersection of Black Bayou and Deer Creek, MISS.,

March 21, 1863.

SIR: I have the honor to report that, in pursuance of Major-General Grant's instructions of the 15th instant, I ordered the Eight Missouri, Lieutenant-Colonel Coleman in command, with 50 pioneers, to embark on the steamer Diligent, and to proceed with all dispatch up the Yazoo and clean out the channel leading thence up Steele's Bayou.

This party subsequently received instructions to follow the admiral up Steele's Bayou to the Big Black, and proceed to clear it of overhanging trees, and in person I repaired on board the flag-ship Black Hawk, and at daylight on the morning of the 16th, in the tug Fern, I followed, overtook the Diligent in Steele's Bayou, and passed on and overtook the fleet of gunboats just as they were entering Deer Creek.

There I met Admiral Porter, with whom in a tug I proceeded up about 3 miles to Fore's plantation, and returned to this point. My orders were to see as to the practicability of moving my corps from Young's Point to some tenable position on the main land east of the Yazoo, from which to operate against Vicksburg and the Yazoo forts at Haynes' Bluff. Admiral Porter proposed to move up Deer Creek to the Rolling Fork, thence into Sunflower, and so to the Yazoo, below Yazoo City, and he first proposed to leave one gunboat, the Louisville, at this point, and to reconnoiter with the other four and the tugs.

I was to remain here till he went above. The same night, Monday, he sent orders back for the Louisville to follow, whereupon I disembarked the Eight Missouri at this point as a guard, and sent the pioneers to work in cleaning away the trees and brush in Black Bayou. This is about 4 miles long, narrow, crooked, and filled with trees.

The heavy iron-clads could force their way through, pressing aside the bushes and trees, but the transports could not follow. The Eight Missouri passed through on a coal-barge, drawn by a navy tug. Other pioneers and negroes have been sent up by Major-General Grant, among them two companies of Colonel Bissell's regiment, all of whom are busy, and have so far progressed in their work that yesterday the Eagle and Silver Wave came up far enough to land two regiments, viz, the Sixth Missouri and the One hundred and SIXTEENTH Illinois, at the first ground above water from the Yazoo to this point. They have backed out and gone down to Eagle Bend for more troops.

On Tuesday, in a tug, I reconnoitered up Steele's Bayou to see if I could reach the Rolling Fork by that route, but found it utterly impracticable for a small tug, much less a transport. All the country on both sides was deep under water. I next examined the left fork up to and beyond the Tallulah Bridge, but the bridge is swept away and the road deep under water. Indeed, all the country bordering Steele's Bayou is submerged swamp. Satisfied that the only dry land in this climate was to be found here on Deer Creek, I returned, and renewed the orders to push the work in clearing out Black Bayou.

Learning that General Stuart's DIVISION, of my corps, had been sent up to the Muddy Bayou, I proceeded down on Thursday to see what progress they were making in getting across to Steele's Bayou, and found the DIVISION there, with two regiments, the Sixth Missouri and One hundred and SIXTEENTH Illinois, embarked in the Silver Wave, which started out, and General Stuart accompanied me. Our tug broke her rudder, and in the night carried away the smoke-stack, which disabled her all day yesterday; but she is now repaired, and will be used in towing an empty coal-barge freighted with soldiers as they arrive.