The detached expedition to Yazoo City, under Lieutenant-Commander Walker, had returned on the evening of the 23d. On the approach of the vessels, the Confederates had set fire to the navy yard and three steamers on the stocks building for ships of war, one a very large vessel, 310 feet long by 70 feet beam and intended to carry 4½-inch plating. All that had not been destroyed or removed by the enemy the gunboats finished, the loss being estimated at two million dollars. An attack was made upon the gunboats at a bend of the river by a small force of riflemen with three field pieces, but was repelled without trouble, one man only being killed and eight slightly wounded. The morning after their return the same vessels were again sent up. One of the light-draughts, the Signal, met with the curious accident of knocking down her smoke-stacks, an incident which again illustrates the peculiar character of this bayou warfare. Sending her back, and leaving his own vessel, the De Kalb, to follow as rapidly as possible, Walker pushed on with the Forest Rose, Linden, and Petrel to within fifteen miles of Fort Pemberton, by which the Yazoo Pass expedition had been baffled. Here four fine steamers had been sunk on a bar, stopping farther progress. Having no means of raising them, they were fired and burned to the water's edge. The vessels then passed down the Yazoo, burning a large saw-mill twenty-five miles above Yazoo City, till they came to the Big Sunflower River. They ascended this stream one hundred and eighty miles, branch expeditions being sent into the bayous that enter it, destroying or causing the destruction of four more steamers. Transportation on the Yazoo by the Confederates was now broken up below Fort Pemberton, while above it a few steamers only remained.
From this time until the surrender of Vicksburg little occurred to vary the routine siege operations. Thirteen heavy cannon, from IX-inch to 32-pounders, were landed from the fleet to take their place in the siege batteries, in charge, at different points of the lines, of Lieutenant-Commander T.O. Selfridge, and Acting-Masters C.B. Dahlgren and J.F. Reed; and as many officers and men as could be spared were sent with them. Three heavy guns, a X-inch, IX-inch, and 100-pound rifle, under the command of Lieutenant-Commander F.M. Ramsay, of the Choctaw, were placed in scows close to the point opposite the town, but where they were protected by the bank, enfilading the batteries and rifle-pits on the enemy's left, against which the Cincinnati had made her unsuccessful attack. The gunboats below were constantly under fire and the mortars steadily shelling. On the 19th of June Grant notified the admiral that he intended to open a general bombardment at 4 A.M. the following day and continue it till 10 A.M. The lower division, the scow battery, and the mortars joined in this, shelling the hill batteries and the city, but no reply was made by the enemy from the water front.