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Carnedd Dafydd cairn is a prehistoric round cairn situated in Wales and protected as an ancient monument by Cadw under reference CN367. The structure was constructed on bedrock comprising Ordovician felsic tuff, an extrusive volcanic rock formed during the Ordovician period over 440 million years ago. This geological foundation of ancient volcanic material would have been exposed or partially buried when the cairn was built during the Bronze Age or earlier prehistoric period, creating a substantial natural base for the monument's construction.
The cairn was built by stacking stone over a likely central burial chamber or ceremonial deposit, a typical practice for funerary monuments of prehistoric Britain and Wales. The volcanic tuff bedrock that underlies the site consists of compacted ash and rock fragments ejected from ancient volcanic activity, providing a firm and stable foundation. Such stone-rich geological conditions in Wales made the upland landscape ideal for cairn construction, as suitable materials lay naturally at hand.
The monument remains a significant survival of Welsh prehistoric architecture and funerary practice. Its Ordovician bedrock, among the oldest rock formations in Britain, anchors the cairn within the deep geological history of the Welsh landscape, linking human ritual practice to the ancient Earth movements that shaped the region's bedrock.
Carnedd Dafydd cairn is a scheduled monument protected by Cadw under reference CN367. View the official record →
Carnedd Dafydd cairn is a prehistoric round cairn situated in Wales and protected as an ancient monument by Cadw under reference CN367.
Carnedd Dafydd cairn dates from the prehistoric period, and is classified as a round cairn. It is one of over 32,000 scheduled monuments protected across the UK.
Carnedd Dafydd cairn is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is CN367.
Several scheduled monuments lie within 10 km, including The Holyhead Road: the Ogwen Pass (2.7 km), Hut Circle Settlement at Nant Bochllwyd (3 km), Nant Ffrancon Anti-invasion Defences (3.2 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Carnedd Dafydd cairn's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Carnedd Dafydd cairn stands on Unnamed Extrusive Rocks, Ordovician, bedrock that formed in the Ordovician. The rock here is felsic tuff.