Anacostia, and engaged the Confederate batteries for several hours, again with little effect. The largest guns of the squadron were 32-pounders. On June 1, the Thomas Freeborn, Anacostia, Resolute, and the sloop-of-war bombarded the batteries for almost 5 hours, firing over 500 rounds. Captain Lynch reported no deaths or injuries from the second and third days of shelling, only the death of a chicken and a horse. Lynch added that his works sustained some damage, houses in the rear were "knocked about" and the railroad was torn up in three or four places. Lynch said that he returned fire sparingly in order to save ammunition and because he could fire only when the ships came in view and range of his embrasures as the big guns could not be turned. Nonetheless, during the fight both the Thomas Freeborn and the Pawnee took minor damage from the batteries and required repairs. No Federal sailors were seriously wounded or killed. Aftermath On June 27, 1861, Commander James Harmon Ward became the first United States Navy officer killed during the American Civil War. He was killed while his vessel, the Thomas Freeborn was giving close support to a landing party which was attempting to silence another Confederate battery and to set up a Union battery along the Potomac River at nearby Mathias Point in King George County, Virginia. Following the battle of Aquia Creek, the Confederates reinforced their defenses in the area by constructing a third battery on the bluff at Aquia and a fourth across the mouth of Aquia Creek at Brent Point. On July 7, Confederates placed mines off Aquia Creek in the Potomac River, marking the first such use in the war. The mines, which were 80-gallon casks supporting a boiler-iron torpedo and enough gunpowder to blow up a ship the size of the Pawnee were spotted by Pawnee sailors as the devices were floating toward them. The mines were later removed from the river by sailors from the Resolute, although one of the mines actually sank into the river. By the end of October 1861, the Confederate batteries effectively closed the Potomac River for a short time until the Union Navy slowly discovered that the batteries could not hit passing vessels, probably due at least in part to poor quality gunpowder. Despite the Union Navy's conclusion about the lack of threat from the Confederate guns, the Navy forbade civilian