Annadorn dolmen has a large, low, slightly displaced capstone about 65 cm thick covering a rectangular chamber and supported by three stones about 60 cm high. An account of 1802 suggests that it was formerly set beneath a large rectangular cairn 60 ft in diameter and approached by a lintelled passage, so it could be the remains of a passage grave.
Another possible explanation could be that the supporting stones were originally upright supporting the capstone, representing a more typical tripod dolmen. The monument has not been excavated and closer examination would be required to correctly interpret the site. The capstone has many small solution pits on the upper surface, two of which appear to have been enlarged. The 1802 account also says the chamber under the capstone contained ashes and a number of bones.
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.