a. The denuded long cairn at Carneddau Hengwm measures c.52m E-W by 17m. Set within the cairn are an uncertain number of chambered features, some of which appear to have retained their capstones: a second, similar cairn lies some 44m to the N (Nprn401800).
Source: Bowen & Gresham 1967 'Hist. Merioneth', 9-15.
J.Wiles 04.11.04
b. One of two chambered cairns on Mynydd Egryn. This the South Cairn is said to be 200 feet long and 70 feet broad, aligned E-W and has two or three possible chambers one of which appears to have survived with its roof intact and can still be entered. Although well preserved as a site it is very evident that a large amount of stone from what must have been an enormous and dominant site, has been removed to build structures locally as well as the parliamentary boundary wall that (unfortunately) cuts through the site, dividing the "ceremonial portal" at the E end from the main body of the cairn. Two large uprights and a fallen slab (which may have been a capstone) survive of this Portal. Thomas Pennant writing in 1780 saw the tomb, apparently before it was damaged, and stated that it had two overlapping capstones. It is possible that the original tomb concept was the Portal Dolmen demonstrated by the surviving uprights and fallen capstone at the E and was later added to by a long cairn with lateral chambers to the W in the Severn Cotswold style more clearly demonstrated in the layout of the N cairn nearby (NPRN 401800).
John Latham RCAHMW 4 June 2019
Source: Muckle Partners, Archaeological Survey of Egryn for The National Trust (unpublished report) 2003.