A distinctive type of pottery produced in Derbyshire from the mid 2nd century AD through to the 4th century AD. It is hard and gritty with a surface that is sometimes described as being like ?petrified gooseflesh'. color varies from grey and light-brown to red. The surface texture is due to the presence of silica particles in the local clay. All vessels are jars, mostly with a lid-seating on the rim.