Two parallel, short, stony banks running north-south to the west of the Grwyne Fawr reservoir. They were both 1m wide and 0.20m high with 3m in between them. One was 4m long and the other 7m. When recorded in September 2007, they were largely turf covered. Their purpose was unknown but probably connected with the building of the Grwyne Fawr reservoir in the early 20th century. J.J.Hall, Trysor, 27 September 2007