The basal notches have a concave shape resulting from the excavation of the rock walls by the breaking water jets. The potholes correspond to excavated depressions in the granites, resulting from the combination of the kinetic force of the waves with the pebbles and boulders that are found there, the circulation movement of these sediments leads to the deepening and widening of these structures over time.

These geoforms represent testimonies of the Atlantic erosive action, during the last interglacial period 130 to 115 thousand years ago (Eemian period), and are considered excellent markers of the sea levels existence and position, certifying in this Natural Monument the 5 meters coastal platform (IV).