Joan Baez sings, "Stonewall's cavalry" on the cover version that was released as a single. In a later cover version (possibly a live concert recording) she sings, "so much cavalry." I suspect that someone corrected her, or she forgot the lyrics...

Union Major General George Stoneman, West Point class of 1846, commanded the Cavalry Corps in the Army of the Potomac in 1863. Before that, the north did not deploy large cavalry units (brigade & divsion size) to protect their armies' flanks and to perform reconnaissance.

Stoneman later commanded the Cavalry Corps in the Army of the Ohio. The song refers to that latter command in early 1865 -- during which Stoneman's cavalrymen wreaked havoc behind the Confederate lines as several Union armies closed-in on Lee's army.

Confederate General Thomas J "Stonewall" Jackson was mortally wounded in May 1863 at the Battle of Chancellorsville, so he was not alive when "they drove ol' Dixie down." Jackson commanded the II Corp of the Army of Northern Virginia (Robert E. Lee's army). Oddly enough, Jackson had been George Stoneman's roommate at West Point.

Decades after the war, Stoneman was elected governor of California. He authorized the construction of a hotel in Yosemite Valley, the Stoneman House. The original hotel burned down in the 19th century, but its namesake stands in the shadow of Glacier Point.

Maybe we should record a new version and sing, "Schwarzenegger's cavalry" or "Arnold's cavalry,"

http://en.wikipedia.org/wiki/George_Stoneman