A building footprint defined by concrete footings, measuring 7m north-south by 5m on a level area on the southwest side of the Grwyne Fawr river, just below the reservoir. The area was overgrown with grass and nettles when recorded in September 2007. It seems likely that this is the remains of a building connected with the construction of the reservoir along with NPRNs 267137 and 267138. J.J.Hall, Trysor, 27 September 2007