These ruins are located above Iso Tunnel on Route 330 and are from the Shell Mound Period about 3,000 years ago. During excavations, Ichiki type earthenware from Kyushu was uncovered which evidences the exchanges between Kyushu and the Ryukyu Islands in the Jomon Period (till 200 BC). Pit dwellings were discovered on the cliff above and below it is the shell mound.