I believe that your great grandmother may have been Sarah H. "Sally" Nix b. 1854 who later married someone with the last name Funderburk. The records I have indicate that Sally's nephew William Barney Nix b. 1892 was married in Buckner, Lafayette Co., AR.

If this is your great grandmother, her parents were John Wilson Nix b. around 1827 and Sarah Caroline Sparks b. around 1832. They married 2 Sep 1847 in Monroe Co., MS. John W. Nix died in Arkansas 20 June 1891. Sarah Caroline Sparks may have died in 1894.