The stones in Penrhos Feilw were probably set in the Bronze Age, around 2000-1500 BC, but it is not known by who and for what purpose it were built. Stones could have cult significance and be used for religious purposes, although no burials or remains of sacrifices were found nearby. They could also be an indication of the place of tribal gatherings, or the construction of the site was never completed and it was not used at all.
The stones are about 3 meters high, 0.9 meters wide at the base, only 20 to 30 cm thick, and have similar shapes. They were laid on a flat, open and grassy place between two low hills along their long axes in the north-east and south-west directions, at a distance of about 3.3 meters from each other. Most likely, they were not part of the stone circle that was supposed to be around them according to the local tradition. Reports that a small ossuary (cist) was found nearby have not been confirmed.
The Royal Commission on The Ancient and Historical Monuments and Constructions in Wales and Monmouthshire. An Inventory of the Ancient Monuments in Anglesey, London 1937.