Ordovician cephalopods from the Maggol Formation of Korea

抄録

A cephalopod fauna consisting of 11 species belonging to 7 genera is described from the Lower Ordovician Maggol Formation near Taebaeg City in South Korea. The fauna includes two new species, Ormoceras weoni and Michelinoceras cancellatum, and Wutinoceras, a primitive genus of the family Actinoceratidae first reported from South Korea. Ormoceras cricki from the Middle Ordovician Duwibong Formation occurs in the uppermost horizon of the Maggol Formation, and thus may be regarded as a forerunner of the ormocerids in Korea. The Maggolian cephalopod fauna comprising Wutinoceras robustum, Kogenoceras nanpiaoense, and Manchuroceras spp. shows closest affinities with those from the Setul Limestone of the Langkawi Islands, Malaysia and from the Beianzhuang Formation of Hwangho Basin, North China. This fauna is, therefore, assigned in age to the late lbexian to early Whiterockian in the American Early Ordovician scale.