The Sant Pol beach
The Sant Pol beach has undergone an intense urban transformation, but the coastal dunes are still recognizable (fine sands accumulated by wind and fixed by vegetation) between the seafront and the beach. A peculiarity of this cove is that under water (between -0.5 and -2.5 m) there is a submerged fossil beach, a sand and gravel slab cemented by calcium carbonate that extends from end to end, in parallel to the coast.
The sand on the beach comes from the erosion of the continent, transported through Sant Pol and Segueró rivers. Waves are responsible for redistributing it to one side and the other. Only a small fraction comes from the sea (for example, the shell fragments). During the storms, part of the sand moves towards the seabed.