http://www.atlantisquest.com/Carnac.html
Several nearby islands exhibit stone circles (cromlechs) which are partially or completely submerged. Pierre Mereaux, a French engineer in thermodynamics who has made a study of the stones, comments:
"On the Island south of Gavr'Inis in the Gulf of Morbihan there are 2 tangential circles; 28 stones in the north circle, 32 in the south circle; the stones are 2-5 meters high. Half of the north circle and all of the south circle are submerged--evidence that the sea level has risen and the Gulf flooded since the circles were built." (Mereaux, 1992)