A team from the Welsh Rock Art Organisation has begun excavating Ynys Môn's least-known Neolithic chambered tomb - Perthi Duon, on Anglesey, in northwest Wales - one of eighteen existing stone chambered monuments that stand within a 1.5 kilometre corridor of the Menai Straits.
     In 1723 the antiquarian Henry Rowlands reported three possible upright stones beneath the large capstone, however by the time the Reverend John Skinner sketched the site in 1802 it was in a ruinous state.
     The probable orientation of the entrance is east-west, with its concealed chamber at the western end. The team have so far uncovered several significant features, including areas of compacted-stone cairn that would once have formed a kidney-shaped mound surrounding the chamber.
     Team director Dr George Nash says that "This discovery, along with other excavated features clearly show this monument to be a portal dolmen, one of the earliest Neolithic monument types in Wales, dating to around 3,500 BCE. More importantly, the architecture of Perthi Duon appears to be a blueprint for other portal dolmen monuments within what is termed the Irish Sea Province. We hope, by the end of this excavation to gain a better understanding of the burial and ritual practices that went on at this site, some 5,500 years ago."

Edited from University of Bristol (21 March 2014)