Gwynedd Archaeological Trust
Regional Historic Environment Record

Round Cairn, Trwyn Du, Aberffraw

Primary Reference Number (PRN) : 3003
Trust : Gwynedd
Community : Aberffraw
Unitary authority : Ynys Mon
NGR : SH35236787
Site Type (preferred type first) : Bronze Age ROUND CAIRN
Status : Scheduled Monument

Summary :
Approximately 5000 years after the site was used for Mesolithic flint working, an Early Bronze Age burial mound (cairn) was constructed on top of the earlier ground surface at Trwyn Du (in c. 2000 BC). The cairn was excavated in 1956 by C. Houlder, and was found to have been built over a narrow D-shaped grave (similar to that found at Tyn y Pwll, Llanddyfnan, Anglesey). The body did not survive due to the acidic conditions created by sandy soil.

The mound was built of stone - mainly boulders and large water-rolled pebbles - retained by an unusual kerb of large slabs. The slabs were alternately one large and two small, and six of the larger stones are still visible through the grass. Excavations by R. B. White in 1974 also revealed a smaller, un-edged cairn immediately next to the main cairn.

Description :
This is a Bronze Age round cairn, overlying a Mesolithic flint industry excavated by C. H. Houlder in 1956. About 60% was excavated at that time which yielded a 'D'-Shaped enclosure. It was a Bronze Age grave with no trace of a body.

Trwyn Du is on the coast today, it would have been 2 or 3 miles inland during Mesolithic occupation, therefore it can be described as inland rather than coastal. By summer 1974 erosion had resulted in a hole 6m square cutting through and destroying old ground surface. The soil was sieved and 563 pieces of flint and a range of implements comparable to those already published were found.

The excavations in 1974 produced 7000 flints and rough outs for 2 Neolithic axes. There were also a number of flint packed pits. Occupation was dated to the first half of the C7th BC.

The cairn is probably beaker. The 'D'-shaped arrangement of stones in the grave parallel to other sites on Anglesey and Glamorgan. In the absence of dateable finds, all that can be said with certainty is that the cairn post dates the Mesolithic deposits over which it is built, for the cairn is 7000BC. The kerb around the cairn shows work of the Bronze Age of a more sophisticated structure, from an archaeological point of view, than simple piles of stone or turf.

Two tranchet axes were found showing the direct response to the spread of forests which characterised the transition from glacial to post glacial periods. <1>

The cairn is now well grassed over although 4 kerb stones can be seen. Because it has been left in a half excavated state after archaeological work it is not obvious what it is. On a low cliff edge promontory, not prominent from the land nearby but provides a dramatic viewpoint and would be prominent to any boats entering the estuary. (Smith, 2003)

The monument comprises the remains of a burial cairn, probably dating to the Bronze Age (c.2300 BC - 800 BC) and situated on the leading edge of the rocky foreshore on the NW side of Aberffraw Sands. The grass-covered cairn is roughly circular on plan and measures about 9m in diameter and up to 0.6m in height. It has been partially excavated in the past (Houlder 1957; White 1978), the work revealing a well-preserved kerb cairn coincidentally overlying flint debris and occupation material of early Mesolithic date (c.7000 BC). <5>

Sources :
Smith, G. , 2003 , Prehistoric Funerary and Ritual Monument Survey: West Gwynedd and Anglesey ( © GAT)
Smith, G., and Steele, N. , 2005 , Pan-Wales Prehistoric Funerary and Ritual Sites Survey: Trial Data Synthesis ( © GAT)
The Royal Commission on the Ancient and Historical Monuments of Wales , 1937 , An Inventory of the Ancient Monuments in Anglesey
White, R. B. , 1978 , Archaeologia Cambrensis , <1>
Savory, H. N. , 1957 , Proceedings of the Prehistoric Society , <2>
Lynch, F. , 2009 , Anglesey Past Landscapes of the Coast , <7>

Events :
42642 : Excavations at Trwyn Du, Anglesey, 1974 (year : 1974)
40526 : Prehistoric Funerary and Ritual Monument Survey: West Gwynedd/Anglesey (year : 2003)
40527 : Pan-wales Prehistoric Funerary and Ritual Sites Survey: Trial Data Synthesis (year : 2005)

Related PRNs : 302323

Compiled date :

The above data are supplied by GAT in partnership with its Local Authorities (Anglesey, Conwy and Gwynedd County Councils, and Snowdonia National Park Authority), © GAT 2019 (and in part © Crown, 2019 - as indicated)
This information is supplied for the purposes of personal interest only and may not be used as part of a commercial project.

March 25, 2019, 3:32 am - HTML file produced from Gwynedd Archaeological Trust Regional HER
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