I did a Google search for the Holt Cemetery but only found the same info you did; Gaul surname with no other info. Also there wasn't any contact info for the cemetery.
Sometimes local historical and genealogical societies keep track of who was buried in cemeteries in their county. I'd contact the Genealogical Society of Whitley County, http://whitleycountyin.org/
and the Whitley County Historical Society, http://whitleycountyin.org/
. Successful Searching!