This is a Geosite consisting of a rocky coast with coastal cliffs, coastal caves, and strangely shaped rocks formed by the erosion of the lava ejected in volcanic activity after the Sea of Japan was formed (in the Pliocene Epoch), and a sandy beach of squeaking sand. In this Geosite, there are three fishing ports: Natsudomari Port where female divers catch seashells, Aoya Port which once prospered as a junction port on the Kitamaebune―a shipping route to and from the north of Japan―and Nagawase Port which was recently constructed. These three fishing ports tell you the history of how this area has been developed.