Millstones; Mill stones
Usually a pair of flat cylinder shaped stones driven by some machinery to grind materials. These are large than quern stones. These are circular and have grooves cutting across the upper surface of the lower stone to aid the milling process. There were millstone extraction sites across the region, see especially Harbottle Common and near the Millstone Burn, Northumberland. A shape was pecked out and wedges inserted to lever the stone out - some failures may be still found uncompleted or by trackways. Millstones were a famous export of the northeast.