Ancient Monuments

History on the Ground

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Twyn Bryn Glas round cairn

A Scheduled Monument in Vaynor (Y Faenor), Merthyr Tydfil (Merthyr Tudful)

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Latitude: 51.7943 / 51°47'39"N

Longitude: -3.4731 / 3°28'23"W

OS Eastings: 298501

OS Northings: 211657

OS Grid: SN985116

Mapcode National: GBR YK.Y556

Mapcode Global: VH5G7.R579

Entry Name: Twyn Bryn Glas round cairn

Scheduled Date: 13 January 2004

Source: Cadw

Source ID: 4010

Cadw Legacy ID: GM561

Schedule Class: Religious, Ritual and Funerary

Category: Round cairn

Period: Prehistoric

County: Merthyr Tydfil (Merthyr Tudful)

Community: Vaynor (Y Faenor)

Traditional County: Brecknockshire


The monument comprises the remains of a round cairn probably dating to the Bronze Age (c.2300 BC - 800 BC). The cairn is situated in open moorland on the saddle between two prominent rocky knolls immediately to the south-east of Cadair Fawr. The cairn is circular on plan and measures about 10m in diameter and up to 0.6m in height. The cairn was partially excavated in 1958 (Webley 1962) and, having opened four small trenches and excavating to the bedrock beneath (and also exposing the earthfast structures in their entirety beneath the cairn material), the excavator described three periods of construction.

The monument is of national importance for its potential to enhance our knowledge of prehistoric burial rites and ritual, social organisation and the environment. The feature is an important relic of a prehistoric funerary and ritual landscape and retains significant archaeological potential. Its importance is further enhanced by the presence of an excavation report pertaining to a relatively early period of scientific field archaeology.

The area scheduled comprises the remains described and an area around them within which related evidence may be expected to survive.

Source: Cadw

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