parallel rock formations on sea shore in tidal zone of sea outdoors La Rasa Mareal flysch cliffs algae alga algal growth Basque Country Spain Europe

alga algae algal artificial atlantic basque bay beach beaches biscay cliffs coast coastal country ebb eroded erosion europe flood flysch formations geologic geology gipuzkoa growth high la low mareal natural nature ocean outdoors parallel parallels rasa rock rocks rocky sea shore spain steep stone stones stony tidal tide tides washed zone zumaia