geophagy Look up geophagy at Dictionary.com
"dirt-eating," 1850, from Gk. *geophagia (the actual Gk. was geotragia), from geo-, comb. form of ge "earth" + phagein "to eat."
"A diseased appetite ... prevails in several parts of Alabama, where they eat clay. I heard various speculations on the origin of this singular propensity, called 'geophagy' in some medical books." [Lyell, 1850]