The megaliths of the Alignement de la Grée Galot (also known as Alignement de l’Orme d’à-Haut) are located on the border between Sion-les-Mines to the north and Lusanger to the south, in the northern part of the Loire-Atlantique department in France.
This is the only known stone row in the department. Of the originally nine blocks, seven have fallen or disappeared over the centuries.
The stone row now consists of seven main blocks made of quartz sandstone. Starting from the west, the second and third monoliths still stand, measuring 1.2 and 1.8 meters in height, respectively. The others lie on the ground. The sixth block, about 2.0 meters long, was split in half in 1825 to serve as a megalithic bridge, which was unsuccessful. Another megalith is found in the street.
According to Jean-Philippe Bouvet, the stone row has been recorded in the local cultural atlas since 1782. In 1788, there were still seven stones oriented east-west over a length of about 13 meters. Five had already fallen when the last edition of the Dictionnaire de Bretagne was published in 1853. At that time, Pitre de Lisle du Dreneuc (1846–1924) made a sketch that is very similar to the current state.