Pierres Plates, Neolithic dolmen in Locmariaquer, France

Pierres Plates is a large megalithic burial structure from Neolithic times located near the coast of Locmariaquer. The structure consists of stone corridors with a side chamber and is formed by standing stones and flat capstones arranged into an enclosed passage.

The megalithic burial structure was built during the late Neolithic as a communal burial place for regional populations. Early archaeological work in the 1800s uncovered carved stones and evidence of ritual activity within the passage.

Twelve upright stones inside the passage carry carvings, mostly scutiform motifs shaped as cartouches split by vertical lines and filled with circles and horseshoe forms. Some researchers read them as fertility figures with multiple breasts; others once saw palms or scarabs. One carved stone is kept at the Musée de Préhistoire in Carnac.

The dolmen lies in the dunes a few metres above a sandy beach on the south side of the Locmariaquer peninsula, reached by a worn path up the bank. The entrance passage is only about 1.40 m high, so visitors stoop to look inside; the main chamber beyond the bend rises to about 1.75 m. Much of the walling above the upright stones is filled with small rubble, rebuilt during the 1931 restoration under Zacharie Le Rouzic.

The passage bends about 120° roughly six metres in, and a small side chamber opens westward at the elbow. Most of the 38 upright stones are granite, but four, including the main chamber's capstone, are orthogneiss, probably pieces of a deliberately broken large menhir.