In the spring and early summer of 1977, excavations confirmed the presence of a Neolithic cairn alongside the A40 at Gwernvale. This Cairn was of the Severn/Cotswold Tradition and was dated at around 3.000 B.C.
Realignment of the roadway to the south of the site, coupled with the necessary landscaping of the verges, provided additional areas for excavation. The main excavation of the site took place between March and September 1978, under the auspices of the Clwyd Powys Archaeological Trust. This excavationon revealed the existence of a trapezoidal (wedge-shaped) cairn, over 45 metres in length, having a recessed forecourt at its eastern end.
The cairn was found to enclose three chambers with a possible fourth chamber or cast at the western end. The cairn was oriented east/west and edged by an inner and outer dry-stone wall of which only the lowermost courses have survived to the present. The capstones to the chambers had not survived, although it is known that the capstone of chamber 1 was removed in 1804 and it is likely that the cairn as a whole had become ruinous by this time, the northern and western extremities being overrun by the main road.
For more information and photographs, click the links below.
http://www.stone-circles.org.uk/stone/gwernvale.htm
http://www.megalithic.co.uk/article.php?sid=4060
Footnote
As we reported in our winter newsletter of 2016, the cairn has, in recent years, become overgrown with vegetation. We undertook enquiries in 2013 but renewed our efforts in 2017 and were informed that the site is owned by the Welsh Governments Trunk Road Agency and that Cadw were working with them to “put together a programme of consolidation and re-presentation.” No timetable was given.
We were delighted to note that in January of this 2017 Cadw had carried out the work on clearing the vegetation from the stones. The cairn is now looking much better. Thank you Cadw, a job well done.
Crickhowell History Society 