Some 130m west of Carn Pen-y-clogau (NPRN 84092) in a slight hollow lie the remains of cairn or ring cairn. It is badly denuded and consist of a consolidated ring measuring. It survives as a ring bank 1.5m wide and 0.3m high, discontinuous on the north, enclosing an area measuring 4m across. A stony mound to the immediate south is possibly spoil from the robbing of a cairn, to leave the ring now visible, or else it may be an entirely separate feature.
This is perhaps the site of Carn Fatho, a cairn believed to be located near to Carn Pen-y-clogau. It was possibly used as a parish boundary marker.

David Leighton, RCAHMW, 5 April 2012