A large quarry working along the rocky escarpment of Graig Ddu. It is shown as a working quarry on late 19th century Ordnance Survey maps and to have expanded on the 1900 edition of the 1:2500 map. The 1919-1920 edition of the map marks this as an ?Old Quarry?. J.J. Hall, Trysor, 21 January 2013