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Garn Las Earthwork is a prehistoric round cairn situated in Wales on bedrock of the South Wales Upper Coal Measures Formation. This geological foundation comprises mudstone, siltstone, sandstone, coal, ironstone and ferricrete deposits laid down during the Westphalian period. The cairn's construction would have drawn upon stone available from the local landscape, materials shaped by the same geological processes that formed the underlying strata.
Round cairns of this type were typically constructed during the Bronze Age as burial monuments and territorial markers. Their form—a mound of stacked stone—allowed them to remain visible across the Welsh upland terrain for centuries. The presence of ferricrete and ironstone in the bedrock would have provided distinctive local building materials that differ from cairn construction elsewhere in Britain.
The monument is protected by Cadw, the Welsh government's historic monuments service, under reference GM236. This recognition reflects its archaeological and landscape significance as a surviving example of prehistoric monumental architecture in Wales.
Garn Las Earthwork is a scheduled monument protected by Cadw under reference GM236. View the official record →
Garn Las Earthwork is a prehistoric round cairn situated in Wales on bedrock of the South Wales Upper Coal Measures Formation. It is designated a Scheduled Ancient Monument by Cadw under reference GM236.
Garn Las Earthwork 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.
Garn Las Earthwork 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 GM236.
Several scheduled monuments lie within 10 km, including Rhos-Gwawr cairn cemetery (4.8 km), Remains of Iron Furnace at Cwmaman (5 km), Brynbychan Round Cairn (6 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Garn Las Earthwork'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.
Garn Las Earthwork stands on South Wales Upper Coal Measures Formation, bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.