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Archaeoastronomy in South Wales

Archaeoastronomy (Introduction)

Neolithic Tombs in GLA & MON

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Stone Circles & Avenues

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Round Cairns & Round Barrows


Enclosures & Ringworks

by Martin J. Powell

The enclosure monuments included in this study represent a somewhat enigmatic group which appear to be related to ring-cairns. The Royal Commission describes them as "more elaborate rings", in most cases having no obvious indications of internal burial pits or cists. Only a thorough excavation would reveal the true nature of these obscure sites.

In Glamorgan county, the most impressive examples are Graig Fawr (SN 628 066), Tor Clawdd (SN 670 063) and Penlle'rbebyll (SN 635 048), which are all located on high ground to the North-east of Pontardulais.  All three contain unusual internal features. Graig Fawr is a perfectly circular stony ring, some 170 ft (52 m) in diameter, with a round structure close to its Southern bank (see a satellite photo of the enclosure on Google Maps). Tor Clawdd (see Google Maps satellite photo) appears to have sockets contained within it, which may once have held upright stones. The ring at Penlle'rbebyll (see Google Maps satellite photo) is open towards the SSE and contains an elliptically-shaped ring, with a crescentic-shaped bank nearby.

Penlle'rbebyll, viewed from the South (10 KB)Penlle'rbebyll, viewed from the South (click for full-size image, 10 KB). The ringwork is about 55 ft (17 m) in diameter and survives to 2 ft (0.6 m) in height. The ring is open to the SSE, with an oval-shaped structure (to right of picture) partly occupying the gap.

The purpose of such rings is unknown, but they are assumed to be of Bronze Age date because of their apparent parallels with sites elsewhere. One suggestion is that they may have served as cattle pounds. Some of them bear similarities with timber circle sites and their associated enclosures across England and Northern Europe (e.g. see Gibson 2005). In considering the possibility that the ring at Graig Fawr could be the remnants of a prehistoric domestic dwelling, the Royal Commission states that "the accuracy which which the outer ring is set out, and the absence of any entrance through the inner [ring], make it unlikely that this is a hut enclosure" (RCAHMW 1976, 54). The apparent existence of an alignment on the Beltane/Lughnasa sunrise, through a raised causeway 7 ft (2.1 m) wide at the ENE of the ring, may indicate that the site's original function was ritual.

A similar sized entrance at the Tor Clawdd ring , this time at the South-east of the ring, may have been aligned on the Moon's most Southerly rising position. The intention of the ring builders may have been to align the entrance upon the full Moon rising up the gentle slope of Tor Clawdd hill, 0.75 miles (1.2 km) distant. However, this site is much smaller than Graig Fawr and consequently the entrance appears relatively wide when viewed from the centre of the ring, making determination of a precise centre-line azimuth very difficult.

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The plan of the peculiar enclosure at Pebyll (SS 910 972), North-east of Abergwynfi, may have been based on an ellipse with a numerical eccentricity of approximately 0.42, its major axis aligned NE-SW (see Google Maps satellite photo). The long axis measures 94 ft (28.7 m) and the short axis is 85 ft (26 m). The major axis line to the North-east and South-west may indicate the Moon at its Northerly and Southerly extremes respectively. Measured from the geometrical centre of the ellipse, two other significant alignments are found at Pebyll; one to a narrow entrance at the North-west, now marked by a single upright slab; the other to a small cist (burial chamber) which is set into the bank at the South-east. Interestingly, no obvious astronomical target could be found for the ring's main entrance at the SSE. Like at Tor Clawdd, Pebyll also appears to have a number of stone sockets within it, most evident along the inner face of the Northern bank. The Royal Commission consider that the site may have been artificially levelled before construction of the ring (RCAHMW 1976, 93-4).

Graig Fawr, a particularly large ring some 170 ft (52 m) in diameter (15 KB)Graig Fawr, a particularly large ring some 170 ft (52 m) in diameter (click for full-size image, 15 KB). The photo was taken from the centre of the ring looking South over the smaller, internal ring. The sight-line from the main ring's centre through its Southern entrance passes just to the left of Twyn Tyle (the dome-shaped hill visible in the photo), 0.4 miles (0.6 km) distant.

In Brecknockshire (a.k.a. Breconshire, South Powys) there are two unusual earthworks, of unknown type, whose entrance directions have not yet been studied in an astronomical context. The double ringwork named Rhyd Uchaf or Llech-Llia (SN 923 189) stands near the well-known Maen Llia standing stone in the Llia valley. It is 82 ft (25 m) by 59 ft (18 m) and has an apparent entranceway at the East (see Google Maps satellite photo). It may have once contained a standing stone (RCAHMW 1997, 78-9). A hengiform monument named Tir yr Onnen (SN 963 129) lies near the River Hepste, to the East of Ystradfellte (see Google Maps satellite photo). It measures 39 ft (12 m) by 36 ft (11 m) and also has an East facing entrance (RCAHMW 1997, 93-4).

The Royal Commission identifies about 18 other ring-cairns in Brecknock county, but only a handful of these have entrance-type features which could be considered worthy of archaeoastronomical examination.

Survey Results (Explanation of Data Table)

Archaeoastronomical survey results for prehistoric enclosures and ringworks in South Wales (29 KB)

Archaeoastronomical survey results for prehistoric enclosures and ringworks in South Wales (click for full-size table, 29 KB)

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BIBLIOGRAPHY

ROYAL COMMISSION ON ANCIENT & HISTORICAL MONUMENTS IN WALES

1976  An Inventory of the Ancient Monuments in Glamorgan Vol. 1. Pre-Norman, Pt. 1: The Stone and Bronze Ages (HMSO, Cardiff).

1997  Brecknock: Later Prehistoric Monuments and Unenclosed Settlements to 1000 A.D. (Sutton Publishing Ltd., Stroud).

GIBSON, Alex

2005  Stonehenge and Timber Circles (Tempus Publishing Ltd, Stroud).

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Archaeoastronomy in South Wales

Archaeoastronomy (Introduction)

Neolithic Tombs in GLA & MON

Neolithic Tombs in BRE & HRF

Stone Circles & Avenues

Stone Rows & Stone Pairs

Round Cairns & Round Barrows

Archaeoastronomy: Enclosures & Ringworks (Full Desktop Site)


Prehistoric Sites in Wales

Prehistoric Sites in England

Prehistoric Sites in Scotland


Copyright  Martin J Powell  2001


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