The constant musketry on our left between 7 and 8 o'clock this a.m. was from the guard in Sedgwick's division, who upon being relieved claim to have proper authority to discharge their pieces. If it is not stopped it will be impossible for us to distinguished real alarms from false ones.

I was relieved by Brigadier-General Berry, of Hamilton's division.

Most of the details were deficient in numbers, and many of the regiments had a very small force. I would recommend that the field officers in charge of working parties and guards, as well as all engineer and artillery officers, be required to report and confer with the general of the trenches by 9 o'clock a.m., and be ordered to make to him a written report of operations during the day and night, so far as necessary to his proper direction of working parties and guards, by 7 o'clock a.m. otherwise upon such a long line it would be impossible for the general to get into communication with these officers and ascertain their requirements and give necessary orders to the guards.

I am, general, your obedient servant,

D. B. BIRNEY.

Brigadier-General, General of the Trenches.

General PORTER, Director.

Numbers 47. Reports of Brigadier General Erasmus D. Keyes,

U. S. Army, commanding Fourth Corps, of operations on the left, April 27-29, with indorsement.

HEADQUARTERS FOURTH CORPS,
Warwick Court-House, April 27, 1862

SIR: I have the honor to report operations on the left during the last twenty-four hours.

Four of the enemy's gunboats were reported in James River yesterday. I saw three. They threw, say, twenty shells, the most of them at Peck's works, but without any damage to the troops. Peck had one man wounded yesterday by the enemy's pickets and another the day before. Brigadier-General Hancock, with a strong force, was out most of the day yesterday. He succeeded in cutting and clearing in front of Smith's left a space of 40 or 50 yards, and by erecting breastworks of logs for his pickets secured them from constant murderous attacks heretofore made on them in that quarter. I have not yet received General Hancock's report, but I derived from a personal interview with him an exact understanding of the enemy's works at a point about 750 yards below the one-gun battery. At that point they are very strong, and can only be reached by vertical fires from our side. The enemy have two dams there, and are busy at something which I do not understand, unless they are preparing for a sortie or for a cross-fire on Smith's batteries. The benefits which we should derive there from 8-inch siege mortars in that quarter would be so great as to justify strong exertions to obtain them. Couch's division have done much in erecting fortifications of different kinds, Smith's have done next in amount, and Casey's have done nothing.

As Lee's Mill is no doubt an extremely strong portion of the enemy's lines, where he could cross and form 15,000 men in a short time, a system of defense to secure Casey from a coup de main is required. I