Dolmen of Guilliguy

The monument is 10.40 m long and oriented east to west. It was built on a rocky outcrop. The chamber measures 6.80 m in length and between 1.40 m and 1.70 m in width. It is bounded by twelve orthostats and is still covered by two capstones. The cella measures 1.80 m in length.

The entrance passage lies at the east end of the chamber and forms an angle of 90° with it. The passage meets the chamber at a slab notched like a porthole, 1.15 m high, 0.76 m wide and 0.15 m thick. A slab of matching dimensions was found in 1992, reused in the construction of a Bronze Age tomb near the entrance to the passage. The entrance is paved.

The slabs are of granite quarried on the spot from a surface outcrop, and the side that had suffered natural erosion was set facing outward. One slab bears a small cup mark 7 cm in diameter and 2.50 cm deep. Seven further small cup marks, 30 to 40 mm in diameter and 9 to 13 mm deep, are visible on a nearby outcrop; five of them are arranged in staggered rows. They were made with a metal tool.

The excavation of 1992 by M. Le Goffic showed that the tomb had been surrounded by a peristalith, a ring of stones that had earlier been mistaken for a cromlech. Five blocks of it, set in an arc, remain visible.