In addition to its recognized ethnographic, cultural and religious relevance, the surroundings of the Sanctuary of Virxe da Barca also have a special geological interest. The origin of these “abaladoiras” rocks is found in the erosion produced by the sea, which creates alveoli in the peripheral regions that give it that characteristic rounded shape. These large rocks would originally be gravitationally supported at two points, so it would be possible to move them with minimal effort. Surrounded by superstitions and legends, they constitute a unique ethnographic and geological element present throughout the Galician coast, but the Piedra de Abalar, the Piedra dos Cadrís and the Piedra do Timón are the best known.