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Trwyn Du round cairn is a prehistoric burial monument located in Wales and protected by Cadw as a scheduled ancient monument under reference AN148. Round cairns of this type are typically Bronze Age funerary structures, constructed by heaping stone to mark the final resting place of prominent community members. The cairn was built directly upon Precambrian bedrock composed of mica schist, metamorphic rock that formed deep within the Earth's crust during the earliest geological period and was subsequently exposed through millions of years of erosion.
The mica schist foundation provides a distinctive local character to this monument, its silvery-grey mineral composition creating a natural stone platform from which the cairn builders quarried material for construction. The Precambrian bedrock of Wales has weathered into characteristic forms that would have been both familiar and practical to those who raised the cairn, providing readily accessible suitable stone for the monument's construction.
The cairn survives today as evidence of Bronze Age burial practices and the relationship between prehistoric communities and their local landscape. Its protection under Cadw ensures the preservation of this important archaeological site for future study and public understanding of Wales's prehistoric heritage.
Trwyn Du round cairn is a scheduled monument protected by Cadw under reference AN148. View the official record →
Trwyn Du round cairn is a prehistoric burial monument located in Wales and protected by Cadw as a scheduled ancient monument under reference AN148.
Trwyn Du round 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.
Trwyn Du round 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 AN148.
Several scheduled monuments lie within 10 km, including Pont Aberffraw (1.1 km), Pen-Sieri Inscribed Stone (3.3 km), Tywyn-y-Parc Promontory Fort (3.4 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Trwyn Du round 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.
Trwyn Du round cairn stands on Precambrian mica, bedrock that formed in the Precambrian. The rock here is mica schist; undifferentiated metamorphic.