Ancient Monuments

History on the Ground

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Clawdd Mawr, Mynydd Caerau

A Scheduled Monument in Glyncorrwg, Neath Port Talbot (Castell-nedd Port Talbot)

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Latitude: 51.6411 / 51°38'27"N

Longitude: -3.5985 / 3°35'54"W

OS Eastings: 289483

OS Northings: 194796

OS Grid: SS894947

Mapcode National: GBR HC.7X5F

Mapcode Global: VH5GY.K0ZS

Entry Name: Clawdd Mawr, Mynydd Caerau

Scheduled Date: 5 July 1955

Source: Cadw

Source ID: 2906

Cadw Legacy ID: GM231

Schedule Class: Monument

Category: Linear earthwork

Period: Early Medieval

County: Neath Port Talbot (Castell-nedd Port Talbot)

Community: Glyncorrwg

Built-Up Area: Blaengwynfi

Traditional County: Glamorgan


The monument consists of a linear earthwork, a substantial bank and ditch forming a major boundary between two adjacent landholdings. It may date from the medieval period. The dyke runs almost straight for 192 metres WNW to ESE at about 490m above OD. It is located roughly 15m above the floor of a narrow saddle running east from Mynydd Caerau, on a slope running steeply westwards. The north end lies at the head of a steep-sided natural gully, the south on a steep slope. There is a gap where a track crosses it, but this appears recent. The dyke has been formed by throwing earth downwards from a ditch on the upper side. Near the north end, the bank and ditch measure about 7.5m by about 1m high overall, but the earthwork steadily decreases in size towards the south end, where it is now merely a shelf about 1.5m wide. There is no sign of stonework.

The monument is of national importance for its potential to enhance our knowledge of medieval defensive organisation and settlement. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits. A linear earthwork may be part of a larger cluster of monuments and their importance can further enhanced by their group value.

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

Source: Cadw

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