A raised, sloping, concrete platform or ramp, running for 20m east southeast - west northwest from SO2318930564 to SO2317630572. At each end the ramp was approximately 2m square but for most of its length it was 1m wide. It had two parallel grooves running down its length, each groove being c. 0.15m wide with c. 0.40 m in between them. The ramp sloped down towards the east southeast, and lay in line between concrete pad NPRN 267149 and mound NPRN 267146 and all features were thought to be connected with the construction of the Grwyne Fawr reservoir in the early 20th century. The feature itself was clear of vegetation, apart from moss and grass growing in the grooves, when recorded in September 2007, and surrounded by grass and reeds. J.J.Hall, Trysor, 27 September 2007