In megalithic archaeology a port-hole slab is the name of an orthostat with a hole in it sometimes found forming the entrance to a chamber tomb. The hole is usually circular but square examples or those made from two adjoining slabs each with a notch cut in it are known. They are common in the gallery graves of the Seine-Oise-Marne culture. Texto de en:Megalithic archeology#Port-hole slab, a donde redirige en:port-hole slab
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Base Mérimée, ministère français de la Culture. Fuente citada en fr:Allée couverte
