The Songjeong Pseudotachylyte geosite is located on a secluded beach in the eastern part of Busan Metropolitan City, and various igneous rocks, such as andesite, andesite tuff, dacite, and rhyolite that compose the Jangsan igneous body, part of the igneous rocks in Yucheon Group formed during the Late Cretaceous. Pseudotachylytes, a fault rock created in connection with the formation of the Jangsan cauldron (volcanic depression), are observed. Pseudotachylyte is formed by frictional melting of the wall rocks during a rapid fault movement and has a very significant scientific value.