OS first edition mapping shows a small oval feature associated with tracks which lead from the Penrhyn farm, the beach of Traeth y Ora and the storehouse at Morfa Dulas (see NPRN 525211). The structure measures 3m x 1.5m with the entrance elongated. The walls are drystone and form a slight bank. The floor is sunk to a depth of 0.3-0.4m. Lewis Morris, the 18th century hydrographer, records the burning of bracken and seaweed in kilns along the eastcoast of Anglesey. Kelp produced soda, which was used in glass making and later iodine production. Burning bracken produced potassium, which was used in soap making, glass making and other industries. The feature's outline is still visible on modern aerial photography.

Sources include:
OS 1st edition 25in mapping
NAW Aerial Photography 2006-9

Maritime Office, RCAHMW, June 2013.