HEADQUARTERS DEPARTMENT OF THE SOUTH,
Hilton Head, S. C., May 28, 1864.

GENERAL: I have the honor to report that the expedition under Brigadier General W. Birney, which had been sent out by General Hatch before my arrival to destroy some bridges on the line of the Charleston and Savannah Railroad, as described in my letter of the 26th instant, has returned unsuccessful.

It appears from verbal reports, which are all I have yet received, that two of the transports, the steamers Edwin Lewis and the Boston, under the conduct of Colonel Thomas Bayley, Ninth U. S. Colored Troops, did not stop at the point designated for disembarkation, but, by mistake, continued on up the Ashepoo River until the steamer Boston ran fast aground within good range of a rebel battery. This battery obtained a direct and raking fire and soon disabled the vessel. The troops on board were saved by swimming and by the boats of the Edwin Lewis, with the loss of their arms. The steamer was then burnt. Our loss is 13 killed, drowned, or missing. Seventy-five cavalry horses and 8 team horses that were on the Boston were burnt with the vessel. The expedition then returned to this point, arriving this morning and during the night. I have ordered a court of inquiry to investigate this matter, and to fix the responsibility for the losses.

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

J. G. FOSTER,

Major-General, Commanding.

Major General H. W. HALLECK,

Chief of Staff.

HEADQUARTERS DEPARTMENT OF THE SOUTH,
Hilton Head, S. C., June 6, 1864.

GENERAL: I have the honor to report that nothing of marked interest has transpired in this department since my letter of the 28th ultimo.

I have visited Morris and Folly Islands, and also the District of Florida. In the former I found the condition of affairs to be satisfactory. General Schimmelfennig has succeeded, with his boat infantry, in driving the enemy's boats out of the creek between Morris and Folly Islands and James Island, and also in keeping close watch on the enemy's operations on James Island and in Fort Sumter.

A line of batteries and rifle-pits now extends from Fort Johnson to Secessionville and thence across to the Stono River. This line is very strong, but there are chances in favor of a surprise, by means of boats and light-draught steamers. These chances are, however, very small, with ordinary vigilance on the part of the enemy. The enemy still hold Fort Sumter, which they are constantly working to strengthen against an assault. I have not yet obtained full information on this point, but hope to be able to report it next week. There are, as in case of the batteries on James Island, some chances of succeeding in an attempt to assault Fort Sumter by means of small boats and steamers. I will communicate the details as soon as I obtain the necessary information. I directed the fire on the