Taken from the on-site information board:
Grand dolmen
Megalithic tomb of the Neolithic
(3200–3000 BC)
This grand dolmen was excavated in 1967. The tomb was surrounded by an oval mound approximately 2 metres high. The surface of the mound reached up to the upper edge of the six lateral supporting stones. These supported two massive capstones.
The roughly rectangular burial chamber was accessed via a narrow passage, approximately 1.5 m long, at one end.
The tomb was constructed using animal or human power. The stones, weighing several tonnes, were moved using traction and leverage via rollers.
The chamber is 5 m long, 1.2 to 1.9 m wide and 1.6 m high. The floor consisted of compacted clay and was divided into several sections by red sandstone slabs.