Quarriers cut millstone blanks from an exposed ledge of gneiss rock beside Mill Rock Branch at the upper end of Sautee Valley. Using hardened steel hammers called mill picks, they cut grooves and ridges to shape the working faces of millstones used in grist mills to grind corn into grits and cornmeal. One surviving millstone is unfinished, while others came from Stovall Mill and Watts Mill. E.P. Williams, owner of the Nacoochee slave dwelling, operated an industrial complex on nearby Sautee Creek where flowing water powered machinery and slaves provided labor, and its grist mill used a millstone similar to these but somewhat larger.