This is a horseshoe shaped cromlech that was originally located just south of Penvenan but after it was excavated in 1963-4 it was moved. It can be seen in Tréguier and is by the estuary on the main road not far from the bridge.
On the original site there was a mound with the horseshoe almost enclosing it. It is about 30m (100ft) diameter and open to the east. There are 50 granite stones are the two that flank the opening are larger. Three of the stones had carvings but they were taken away. When excavated two of the stones that had carvings were found to be set upside down so it was assumed these were recycled stones from a nearby ruined burial chamber.