La Pierre Couvretière dolmen, Neolithic dolmen in Ancenis-Saint-Géréon, France.

La Pierre Couvretière is a Neolithic passage dolmen now reduced to a single visible element: a square capstone of conglomerate measuring 4.20 by 4 metres and 0.70 to 0.80 metres thick. It has tilted about 45° and lies half submerged in rainwater collected in the hollow around it. Two orthostats of siliceous sandstone remain in place, the eastern one 2.50 metres high and sunk 0.60 metres into a schist fissure, the western one 1.50 metres high with a single artificial cupule.

This burial site was built during the Neolithic period as a tomb for multiple individuals from that early population. Excavations in the 1970s revealed tools and pottery from that ancient era inside the chamber.

Local tradition calls it the Pierre du Diable: Satan was promised the people of Ancenis if he reached the town with three stones before the cock crowed, but the crowing caught him in the prairie Saint-Pierre and he dropped his load. The gneiss pillar, a rock not found on site, was brought from several kilometres away. The monument was quarried in the past, and cutting marks remain on one pillar.

The site sits in an industrial area with road access from two different streets nearby, making it relatively easy to locate. Before visiting, it is helpful to check access conditions since it is an ancient monument situated in a modern developed zone.

The capstone is a square slab of conglomerate measuring 4.20 by 4 metres and 0.70 to 0.80 metres thick. It tilted about 45° when the covering mound was destroyed and now lies half submerged in rainwater collected in the hollow around it. It is the only part of the dolmen still visible.