From another source:

>Written by Cool White, [aka John Hodges] it was originally published as “Lubly Fan” in 1844. A favorite of minstrel audiences, its words were easily changed to reflect the location of each performance (e.g. Buffalo Gals, Charleston Gals, Mobile Gals, etc.). The song was popular through the war.

"Lubly Fan" was a bastardization of "lovely fanny".