[3] Pottery found in and around the monument indicates that it underwent a period of reuse in the Bronze Age, in the 3rd millennium BC.

Its first scientific recognition took place in the context of an academic congress in Morlaix in 1850, when it was classified as a tumulus.

The monument overlooks the Bay of Morlaix, probably a fertile coastal plain at the time of its erection.

[5] The 11 chambers of the Barnenez cairn are of the type known as Dolmen à couloir in French archaeological terminology.

Normally, the corbel vault rests on orthostats, in one chamber it actually sits on the ground, forming a true tholos.

They depict bows, axes, wave symbols or snakes and a repeated U-shaped sign.

One of the carved slabs is in secondary use; it was originally part of a different structure, an interesting parallel to the situation in several other such monuments, including Gavrinis.

They included pottery, polished stone axes (of dolerite), flint blades and arrowheads.

Pottery shards found outside the monument indicate that it was reused in the Bronze Age (3rd millennium BC).

Breton examples are Larcuste-Colpo, Le Bono, Petit Mont, Ty-Floc´h, Gavrinis, Île Carn, Ploudalmézeau and Guennoc (I´ile Gaignoc – sometimes spelt Guénioc) off the shore at Landéda.

An exhibition in the modern entrance building explains the results of scientific excavation and displays some objects from the site.