Directly beneath Glossop lie areas of Carboniferous Millstone Grit, shales and sandstone. A stone Iron Age grain millstone (quern) was found close by. Each of the structures consists of Carboniferous limestone overlain with Millstone Grit. A putto sits atop a millstone (or grindstone) with a chip in it. It is a part of the Carboniferous Millstone Grit group. These were followed by dark marine shales, siltstones, and coarse sandstones of the Millstone Grit. Another local area containing Millstone Grit rock stacks is Plumpton Rocks. Only the limestone shaft and sandstone base (a former millstone) survive. The building is constructed of Rawdon Hill millstone grit. Roller grain mills are an alternative to traditional millstone arrangements in gristmills. The summits are capped by Grassington Grit, a variety of Millstone Grit. A typical millstone will have six, eight or ten harps. Bonnie was romantically linked with Asher Millstone, one of Annalise Keating's interns. Okinawan tradition derives the tonfa from a millstone handle. The land on which it is built consists of clay, sand and millstone.