it's not a dolmen. There's only a stone, not very high, which is not easy to qualify. It's possible to see in this stone a boundary too. From an ethnolgical point of view, this stone is linked to rites : little children who have late to walk are carried on this stone. The other name of the Pierre de Grimann is La Pierre du Diable (Devil 's stone).
Most of megaliths in this department (french territorial division) called Les Landes, are chalcolithics and localized in south of this department. This one, if it's a megalith, is in the north part, region totally different of the south, and where there's no chalcolithic context. So, megalith or not, we can't be sure.
Hervé Barrouquère
Archeolandes
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