Genbudo and Seiryudo Caves with beautiful columnar joints were designated as national natural monuments in 1931. There are three features that make these caves famous. Firstly, they have beautiful curvaceous columnar joints. Secondly, the Japanese word for basalt “genbugan” comes from Genbudo Cave. Thirdly, this area is noted as the location where Quaternary reversed polarity was first discovered. In 1926, Professor Motonori Matuyama of Kyoto Imperial University found that the basalt at Genbudo Cave had remnants of reverse magnetization. Based on this fact, Quaternary geomagnetic reversal polarity was first proposed to the world.
*Summary version (The Japanese name “genbugan” for basalt comes from Genbudo Cave. This area is also noted as the location where reversed polarity of the earth was first discovered.)