a. The Carneddau Hengwm North Cairn is a denuded long cairn approximately 35m from east to west by 14.5m showing traces of an uncertain number of chambered features, the most westerly retaining a capstone. A second and similar cairn lies some 44m to the south (NPRN 302786).
Source: Bowen & Gresham 1967 'Hist. Merioneth I', 9-15.
J.Wiles, RCAHMW, 4 November 2004.

b. One of a pair of chambered tombs on Mynydd Egryn, this the north cairn is described as just over 100 feet long and 50 feet broad, aligned E - W., with a number of features as are found typically in the Cotswold Group of barrows. Both the cairns here on Mynydd Egryn are exceptionally well-preserved. They both feature in C17th and C18th century descriptions as they were close to the main north - south route way at the time and essentially on a "tourist route". This the northern of the two cairns in this location is built in the style of a Severn-Cotswold lateral chamber tomb. It has been seriously disturbed over time and the chamber at the W end is not easy now to define. The chamber at E end however has two opposed lateral "entrances" and early drawings of this cairn suggest that there a "false" portal at the E end. In places fine drystone edging survives apparently demarcating the original edge of the cairn. A huge amount of material survives but nonetheless vast quantities of stone must have been removed over time to create field boundaries, sheep folds and the like. and notably the dominant parliamentary enclosure walls (early C19th) that dominate and actually cut through the site of the South Cairn as well as the Scheduled area.
John Latham RCAHMW 4 June 2019
Source: Muckle partners - Archaeological Survey of Egryn for the National Trust, 2003 (unpublished report).