Camp Cobb at Gunnery Springs N-30 In 1775, during the Revolutionary War, this "noble spring" was part of a 10½-acre tract purchased for the Fredericksburg Gun Manufactory. On this site in 1898 stood Camp Cobb, a Spanish-American War training camp for the 4th U.S. Volunteer Infantry Regiment. It was named for Confederate Brig. Gen. Thomas R. R. Cobb, killed in the Battle of Fredericksburg, 13 Dec. 1862. Because of the danger yellow fever posed to American troops in Cuba, recruiters sought to fill the regiment with men whose medical backgrounds suggested immunity to tropical diseases. The first company of the "Immunes," as they were called, arrived on 4 June 1898. The Immunes never saw combat, as the fighting ended in July, and the camp was dismantled.