Rock City, 2.5 mi. s. on SR 106, then .5 mi. w. to 1051 W. Ivy Rd., is a group of about 200 mostly spherical or elliptical sandstone concretions. Ranging from 8 to 27 feet in diameter, they were formed underground by the precipitation of water-borne calcium carbonate in the spaces of loosely cemented sandstone. Erosion of the surface gradually uncovered the formations.