800 metres (2,600 ft) thick) is the uppermost formation of the Hayang Group, belonging to the Gyeongsang Supergroup.

[4] The Hayang Group consists of Chilgok, Silla, Hakbong, Haman, Banyawol, Songnaedong, Chaeyaksan and Geoncheonri Formations in ascending order.

[4] Since plant fossils were first reported in the Geoncheonri Formation in 1925, a series of paleontological studies has been made with molluscs, spores and pollen, charophytes, and dinosaur footprints.

Plant fossils from the Geoncheonri Formation were correlated with the Monobegawa Group and the Gyliak Series (Lower to "Middle" Cretaceous) in Japan.

Yang (1978) noted that the co-occurrence of a pelecypod Trigonioides paucisulcatus in the Geonchonri Formation and in the Gyliakian Goshonoura Group (Cenomanian to Turonian) of Japan.