HEADQUARTERS THIRD DIVISION,
Camp Taylor, Huntsville, Ala., May 15, 1862.

SIR: For more than two weeks the enemy has been landing troops, at several points below the mouth of Elk River, principally cavalry. Their headquarters were at Rogersville, near Lamb's Ferry, and at Bainbridge Ferry, below the mouth of Shoal Creek. From these points Morgan's, Helm's, Scott's, and the Texan Cavalry have started upon their marauding expeditions.

On the very day I received command of the troops posted between this point and Nashville I ordered an expedition against Rogersville, to be commanded by General Negley, which was to rendezvous at Pulaski. Colonel Lytle, of the Seventeenth Brigade, was placed in command of a force to move from Athens and engage the attention of the enemy at the mouth of Elk River. The expedition has proved a success. General Negley, with the troops under his command, moved with the utmost celerity,and has won my thanks and admiration by the rapidity of his movements. Colonel Lytle's force was thrown with great promptitude to the Elk River Ferry, and on yesterday morning, having accompanied Colonel Lytle's expedition as a volunteer, I had the pleasure of greeting the two commanders in Rogersville. The enemy had received intelligence of the Lytle expedition, which was intended only as a feint, and were in the act of removing their baggage and train when attacked by General Negley, whose coming was entirely unanticipated. I supposed he would dispute the passage of Elk River, a most formidable barrier, but in this I was mistaken. He had already fled from Rogersville, and was in the act of crossing his last boat load of troops to the south side of the Tennessee when attacked by General Negley.

An expedition started at 12 meridian on yesterday from Rogersville, to capture Bainbridge Ferry and to destroy the boats. This has been accomplished with great promptitude and success.

We have now possession of all the ferries below Decatur and the shoals, and shall prevent hereafter the passage of any troops to the north side of the river. The ferries from Florence down to Savannah I trust will be guarded by boats sent from the main army at Pittsburg Landing. I have converted a large flat, seized on the opposite side of the river, into a gunboat. She will be ready for service this day, and will doubtless render most valuable assistance on the river in preventing the passage of marauding bands. Having, as I think, effectually cut off the enemy's means of crossing the river below Decatur, and knowing almost exactly the number of troops that have entered and now remain within the region under my command from that direction, after destroying these troops I will turn my attention promptly to the mountain regions bordering upon the Nashville and Chattanooga Railway.

Very respectfully, your obedient servant,

O. M. MITCHEL,

Major-General, Commanding.

Honorable E. M. STANTON,

Secretary of War, Washington.

HEADQUARTERS THIRD DIVISION,
Camp Taylor, Huntsville, Ala., May 15, 1862.

After long and continuous efforts to obtain reliable information of the forces of the enemy which had crossed the river at the ferries below