An old millstone lying in the River Dove at Milldale in Staffordshire, England. The one pictured here is a runner stone, showing the Spanish Cross, carving at the hub. The surface of the millstone bears ten harps, which are in the typical pattern of furrows and lands. Millstones were used in watermills and windmills for grinding wheat and other grains. They were worked in pairs, with the bed stone on the bottom and the runner stone on top.