OS Grid Reference: SH 5887 2284. Neolithic monument consisting of two independent burial chambers stands in a field, 200 feet above sea-level, at the east side of Dyffryn Ardudwy village, Gwynedd, on the western slopes of Moelfre Hill which rises to 1932 feet. Dyffryn Ardudwy is 5 miles north of Barmouth. The ancient monument from about 4000 BC is also known as a ‘chambered cairn’, ‘portal dolmen’ and ‘cromlech’; it goes by several other names including Arthur’s Quoit, Carreg Arthur and Coaten Arthur. These megalithic burial chambers or dolmens can be reached by way of a lane running east off the A496 (coast road to Harlech) just before, or after Bro Arthur, depending on which way you are walking, and then by a short footpath into the fields (passing close by the village school) for maybe 100 metres east of the village. It is marked by a large cairn of stones spread widely about and two burial chambers that are set-apart, each of them having upright slab-stones and huge sloping capstones.

   Some very good information is given in the following description by T. G. E. Powell, MA, FSA (Reader in Prehistoric Archaeology, University of Liverpool), and here quoted in full. He says: “It will be understood that the cairn  had been used over a long period as a quarry for stones to build the neighbouring walls and perhaps older structures no longer visible. Only the basal layers of cairn stones therefore survived, but sufficient to show that it had been roughly trapezoidal in plan, measuring  about 100ft in length, and in width some 35ft at the eastern end and 54ft at the western end. The cairn had a rough edge of small boulders. It’s bulk was made up of loose stones of kinds that could have been collected nearby. The megalithic slabs of which the chambers were built come from grits and slates of the Cambrian series and could have been obtained on the hillside. Excavation disclosed that there had been two periods of construction at the site. First, the smaller, western, chamber had been put up and surrounded by a small oval cairn. Later, but at perhaps no great lapse of time, the larger, eastern, chamber had been erected; then the trapezoidal cairn had been built to envelope everything. Whether this final cairn covered the capstones of both burial chambers cannot be proven, but it is likely that the cairn reached at least as high as their edges.

   “The construction of the western chamber shows it to be of a type often called for convenience a ‘Portal Dolmen’. At the higher, eastern end there is a pair of massive forward projecting stones with a high blocking stone between. These form a portal although one that is blind or non-functional. Access to the chamber was doubtless over the low slab forming the southern side. The floor of the chamber consists of a single large flat rock probably found here in its natural position by the original builders. The markedly sloped position of the capstone resting on the two portal stones and on the end stone of the chamber should be noted as characteristic of the Portal Dolmen type.

   “The eastern chamber was much more ambitious in construction, especially in the width to be spanned and in the weight of the capstone that was raised into position. It was found necessary in 1961-62 to provide additional support for this great roofing stone and a buttress was built on either side of the chamber for this purpose. This chamber stands some 28ft east of the other and is itself some 12ft long, splaying in width from 5 to 7ft. A low cross-slab with broken upper edge should be noted near the eastern end within the chamber. This may have stood to a greater height, thus acting as a partial closing stone. The gap between its free end and the southern side of the chamber was found to have been filled with blocks. A gap towards the rear in the walling of the north side of the chamber may have been intentional as it was spanned only by small flat slabs and no socket for a missing upright came to light. Eastwards of the cross-slab, the projecting walls of the chamber provided a kind of covered portico; then there was an open area bounded by small uprights of various heights, more or less continuing the shape of the portico. Finally, all this area the cross-slab outwards was sealed up with a massive blocking of sloped slabs and cairnstones. 

   “The original contents of the western chamber (Portal Dolmen) are unknown and had doubtless long been destroyed, but a pit under the cairn, just in front of the portal, produced a quantity of potsherds of a recognizable Neolithic ware. The original deposits in the eastern chamber had not been so much thrown out as thoroughly disturbed and mixed up with modern rubbish. Potsherds of several kinds were however found, as well as two polished stone pendants and some traces of cremation burials.”

   T. G. E. Powell in his conclusion of the site at Dyffryn Ardudwy says that: “This chambered cairn is a com-posite burial monument first having consisted of a small megalithic chamber of Portal Dolmen type surrounded by a small oval cairn. The  Portal Dolmen type is widely distributed in the coastlands of Wales, in Cornwall, and in Ireland. The Neolithic pottery found in the pit associated with this chamber at Dyffryn Ardudwy is related  to similar  wares known from Pembrokeshire and Cornwall. It was not possible to obtain any material during the excavation suitable for radio-carbon measurement so that only a suggestion based on other evidence can be given about date. On present information it seems likely that this Portal Dolmen was erected the middle of the third mill. BC. Subsequently, a larger megalithic tomb was built and the cairn proper to this chamber was extended so as to envelope the older monument to the west. The somewhat irregular shape of this cairn may be explained by this factor in conjunction with the slope of the ground. Pottery recovered from the eastern chamber belonged to various types and suggested a period of use beginning a little later than that of the Portal Dolmen, continuing perhaps to the opening of the second mill. BC. The general structural characteristics of the eastern  chamber, and its trapezoidal cairn, suggest a mixing of building practices owing something to the Portal Dolmen tradition, but more to influences coming by pastoral routes through the mountains from the Cotswolds and south-eastern Wales.”

   Chris Barber & John Godfrey Williams (1989) say of this site that: “On early Ordnance Survey maps they are marked as Cromlech and as Burial Chamber on later ones.” Bill Anderton (1991) says that: “As part of an outbreak of light phenomena, columns of light were seen issuing from the ground here in 1905. The site stands on the Morchras geological fault.” Christopher Houlder (1978) describes it as a “long cairn” and also adds that: “The cairn lies in an area of some of the finest Iron Age cultivation terraces in the country, visible on the hillside above.” And Jacquetta Hawkes (1975) informs us that: “The Dyffryn long barrow is approached through the iron gates of the village school and will be found alongside the playground not many yards from the highway. Hawkes goes on to say: “The barrow was excavated in the 1960’s revealing a long and complex history.”

Sources and related websites:-

Anderton, Bill, Guide To Ancient Britain, Foulsham, Slough, Berkshire, 1991. 

Barber, Chris & Williams, John Godfrey, The Ancient Stones of Wales, Blorenge Books, Abergavenny, Gwent, 1989.

Hawkes, Jacquetta, A Guide To The Prehistoric And Roman Monuments In England And Wales, Cardinal (Sphere Books Ltd.,) London, 1975. 

Houlder, Christopher, Wales: An Archaeological Guide, Faber & Faber, London, 1978.

Powell, T. G. E., Dyffryn Cairn – the megalithic chambered cairn at Dyffryn Ardudwy, Merionethshire, Dept of the Environment Ancient Monuments and Historic Buildings on behalf of the Welsh Office – for H. M. S. O, 1973.

https://en.wikipedia.org/wiki/Dyffryn_Ardudwy      The photo (above) from the Wikipedia website is displayed under the Creative Commons Attribution Share-Alike License.

http://cadw.gov.wales/daysout/dyffrynardudwyburialchamber/?lang=en

http://www.megalithics.com/wales/dyffryn/dyffmain.htm

http://www.megalithic.co.uk/article.php?sid=4449

                                                                                     © Ray Spencer, The Journal Of Antiquities, 2017.