[jr.], Captain J. L. McAllister, Lieutenant E. A. Elarbee, and Mr. Motte Middleton.

Three of the monitor fleet took position off the battery at 8.45 a. m., opened fire at 8.45 a. m., and ceased at 4.15 p. m., the action, so far as these vessels were concerned, lansing seven hours and twenty-four minutes. Another monitor lay near the bend of the river below Harvey's Cut, but took no part in the action. She was accompanied by one plain view, and one which was not seen, but which threw mortar shells, together with the other two, during the whole engagement. The three iron-clads were drawn up in line of battle at distances varying from 1,400 to 1,900 yards from the battery. At these distances they appeared to be all so nearly of the same model as to render it impossible to distinguish them by differences of form our proportion. Each carried a single turret nearly amidships and in front of smoke-stack. They could only be distinguished from each other by their differences of color, which are given in the inclosed table. One of them lay above the target, the other two below it. Calling that above the target and nearest the battery Numbers 1, Numbers 2 lay about 300 yards below it, and Numbers 3 about 50 yards below Numbers 2. Their position was in the channel, about 200 yards from the marsh, on the opposite side of the river. Asst. Engr. Postell, stationed at Rosedew, states that one only of the three carried a flag upon her turret. This was probably the Montauk, which in previous engagements carried such a flag. The plates on the hull of Numbers 1 were distinguishable from the battery, and were thought by Mr. McAlpin to be from 118 to 24 inches square. The tables attached to this report will show the differences of color, armament, &c., of the three iron-clads, as well as the number of shot fired by each and the number which took effect upon the battery. The whole number fired was 224, and of these not more than 50 struck any part of our works. Of the 27 which struck the traverses and superior slope only 12 shells exploded, and they did no serious damage. the greatest injury inflicted by a shot was the destruction of the carriage of the 8-inch gun.

The fire of our battery was concentrated exclusively on Monitor Numbers 1. No shots whatever were fired at Nos. 2 and 3. The men on Numbers 3 watched the engagement from the deck of their vessel without fear of being fired at. Captain Anderson reports that he attempted firing by battery, but did not succeed for want of a signal which could be heard in all the gun chambers at once. He reports that the stroke of the bass-drum was not sufficient for this purpose. The firing of the 10-inch mortar (Captain Martin) was very accurate, all the shells falling near Numbers 1, and one filled with sand striking her deck and breaking to pieces. The 32-pounder rifled gun with charges of 7 pounds of powder did well, all the bolts and most of the shells being thrown satisfactorily. The 8-inch gun fired with its usual accuracy until dismounted at 11 o'clock. the firing of the 42-pounder, always accurate, was only interrupted for thirty minutes, when the traverse-wheel, being broken by a fragment of shell, it required that time to replace it. The gun was, however, fired several times with the broken wheel, but at last gave way. The 10-inch gun was served with an elevation of 6^ 30', and generally shot over the turret; it is thought, however, that several of its shot struck the vessel. The 32-pounders were fired I suppose for the purpose of dividing the enemy's attention. It will be thus seen that the 42-pounder and the rifle gun were those which principally maintained the action on