This subrectilinear structure lies on the southern slopes of Garn Gron beyond the eastern end of the Blaen Groes Fechan field system. It is aligned south southeast to north northwest, 8 metres by 4 metres. It is terraced into the slope at the north end, which is rounded, and built up on the south end with a 2.5 metre long semicircular stone spread beyond. The walls of the structure are 1 metre wide where spread, probably 0.7 metres originally, standing to a height of 0.7 metres. There is a possible entrance on the east side. Sunken shelter NPRN 529426, 25 metres to the east, is probably associated with it. J. J. Hall, Trysor, 8th February 2013