Type of quern developed in late prehistoric times with a thick round stationary lower stone in which there is a socket for a spindle, and a hemispherical (beehive-shaped) rotating upper stone that sits over the lower stone. The two stones are held in register by the central spindle which also serves as a chute down which grain can be poured, so that it is taken between the stones near the centre of the quern and gradually moves outwards as it become finer in texture. A socket in the upper stone allows the insertion of a handle to make turning the quern easier.