KOCHIAN STAGE

lowermost and oldest major division of the Lower Cretaceous rocks and time in Japan (the Cretaceous Period began about 136,000,000 years ago and lasted about 71,000,000 years). The Kochian Stage precedes the Aritan Stage and is correlated with the lower portions of the Neocomian Stage, the worldwide standard lowermost Cretaceous stage. It is characterized by fossil ammonite cephalopods.