Archaeoastronomy in South Wales
Stone Rows & Stone Pairs
by Martin J. Powell
At least six stone rows, one avenue and three stone pairs are located within the South Wales region comprising Glamorgan, Gwent (Monmouthshire) and Brecknockshire (South Powys).
A seven-stone row at Saith Maen NW (68 KB, SN 833 154) near Craig-y-Nos castle (Brecknock) is aligned NNE-SSW and has no obvious astronomical significance. It points along the valley towards the Cerrig Duon circle, some 3.4 miles (5.5 km) to the NNE, so in prehistoric times it may have served as a directional marker. The most Northerly site in the study area is also called Saith Maen, situated South-west of Llanwrthwl (SN 949 603). It comprises eight small stones (not seven, as the Welsh name implies) aligned East-West over a length of 24½ ft (7.5 m). Professor Alexander Thom proposed an Easterly alignment to the star Procyon in 1660 BC, and a Westerly alignment towards the equinoctial sunset (Thom 1967, 101; Burl 1993, 240). A third site by the name of Saith Maen SE on Y Wern mountain (SN 861 146) has often been described as a stone row, but the Royal Commision considers it to be a natural boulder (RCAHMW 1997, 161, 180).
The Saith Maen (Craig-y-Nos) stone row, near Glyntawe (click for full-size image, 7 KB). It is 42 ft (13 m) long, aligned on a True bearing of 25º/205º. The tallest stone, which is now fallen, is 9½ ft (2.9 m) long.
The three-stone row of the Harold's Stones (96 KB) in Trellech village, Monmouthshire (SO 499 051) is the most visually impressive of the alignments in South Wales. In this assessment, the alignment is studied towards the North-east, however other reseachers have also considered the alignment in the opposite direction. Fred Hando suggested that they might be aligned on the midwinter sunset, and this was re-enforced by Burl (Burl 1993, 256-7) who gave it an azimuth of ca. 229º and a resulting declination of -23º.5.
Three stone rows in South Wales are located alongside stone circles. In a remote valley in the Brecon Beacons, a small double row of converging stones (technically an avenue) leads uphill towards the Cerrig Duon circle. Six miles (9.6 km) further North, on Mynydd Bach Trecastell, a row comprising at least seven small stones hides in the bracken beside the two Trecastle Mountain circles. In Gwent, two monoliths known as "The Pipers" stand beside a ruinous stone circle on the Southern slope of Gray Hill. Several other stones, recumbent and turf-covered, are positioned along the line of the two upright monoliths, technically making this a stone row (Chadwick & Pollard 2010, 94). Further details of these sites can be found on the accompanying stone circles page.
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Three further stone rows are known in the Brecknock (Powys) region, none of which have yet been studied in an astronomical context. The two stone rows listed by The Royal Commission are located on the North-west facing slope of Mynydd Llangynidr, near the Southern boundary of the Brecon Beacons National Park, North of Tredegar (RCAHMW 1997, 158). The Pant Serthfa row (SO 118 167) is 19½ ft (6 m) long, aligned North-South and comprises four stones, while the Carreg Wen Fawr y Rugos (SO 132 175) stone row is the same length, aligned NW-SE and comprises five stones.
The Harolds Stones, Trellech, looking towards the South-west and the midwinter sunset (click for full-size image, 10 KB). The central stone has two large cup-marks on its South-western face (not visible in the picture).
Also in the Brecon Beacons, three roughly parallel stone rows occupy the South-eastern slope of Craig y Fan Ddu ridge (SO 056 180), North of Pentwyn Reservoir and 5.6 miles (9 km) North of Merthyr Tydfil. A survey by the Clwyd-Powys Archaeological Trust (CPAT) determined the rows to be about 13 ft (4 m) apart and orientated NNE-SSW (roughly in accord with the contour lines of the ridge slope). The Western row is 65½ ft (20 m) long and contains five upright stones and one recumbent; the central row is 42½ ft (13 m) long and has four remaining uprights and one recumbent and the Eastern row has just two remaining uprights which define each end of the 65½ ft (20 m) long row. Two further standing stones and numerous recumbent slabs in the vicinity suggest that this may once have been a significant stone row complex (Jones 2012, 178-9).
In the Gower peninsula two menhirs, one fallen and one upright, in a pasture field to the North of Knelston have been suggested as having been aligned in the direction of the equinoxes (Bowen 1992, 20). The Eastern stone is known as the Burry Menhir (SS 464 901) and after it fell in 1947 it was excavated by archaeologists Hubert Savory and J. G. Rutter. Nothing was found which could help provide either an erection date or an obvious function for the stone. The Western stone, known as Burry Lesser (SS 462 901), is upright but has never been excavated; it is positioned on the opposite side of the field from the Burry Menhir. A study of the potential astronomical lines in both directions shows that whilst the alignment is indeed close to the Sun's declination at the equinoxes (0º) it is imprecise in the Westerly direction and is even less so in the Easterly direction. Alternatively the alignment to the West may have pointed to the Neolithic burial chamber of Sweyne's Howes North (SS 421 899), which is just visible on the slope of Rhossili Down some 2.6 miles (4.3 km) distant and is almost directly in line with the Western stone as seen from the Eastern.
The two stones at Cefn Cribwr (98 KB) near Pyle, Mid Glamorgan (SS 873 826) stand in marshy ground and at the time of the author's last visit (1990) they were not intervisible because of intervening trees. There are a number of partly submerged boulders lying close to the Western stone which may have once formed an alignment, or even a stone circle. The Royal Commission suggests they might even be boundary markers from recent times (RCAHMW 1976, 123). Just across the border in Carmarthenshire, two stones on Mynydd Myddfai beside the Usk reservoir (SN 806 284) are far apart and they may not have originally had any intended relationship with each other.
Finally, a brief mention should be made of a pair of stones in a field at Cae'r-hen-Eglwys (38 KB) near Laleston in the Vale of Glamorgan (SS 875 809). They are often said to be a prehistoric structure, but they are in fact gateposts from a former churchyard (a plan of the church appears in Llewellyn 1895, 325-6).
Survey Results (Explanation of Data Table)
Archaeoastronomical survey results for prehistoric stone rows and stone pairs in South Wales (click for full-size table, 26 KB)
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Archaeoastronomy in South Wales
1992 Ancient Siluria: Its Old Stones and Ceremonial Sites, Llanerch Publishers (Felinfach).
1993 From Carnac to Callanish: The Prehistoric Stone Rows and Avenues of Britain, Ireland and Brittany, Yale University Press (New Haven & London).
CHADWICK, Adrian M. & POLLARD, Joshua
2010 "The Gray Hill Landscape Archaeology Project, Llanfair Discoed, Monmouthshire, Wales" in Lewis, Helen & Semple, Sarah (eds.), Perspectives in Landscape Archaeology (BAR Publishing, Oxford), pgs. 94-106.
HANDO, Fred J.
1944 The Pleasant Land of Gwent (R. H. Johns Ltd., Newport).
JONES, Nigel (CPAT)
2012 Archaeology in Wales, 51.
LLEWELLYN, R. W.
1895 Archaeologia Cambrensis (The Cambrian Archaeological Association, Cardiff).
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).
1967 Megalithic Sites in Britain, Oxford University Press (Oxford).
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Prehistoric Sites in Wales
Prehistoric Sites in England
Prehistoric Sites in Scotland
Copyright Martin J Powell 2001-2017
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