ARITAN STAGE

major division of Cretaceous rocks and time in Japan (the Cretaceous Period began about 144 million years ago and lasted until about 66.4 million years ago). Rocks of the Aritan Stage overlie those of the Kochian Stage and underlie those of the Lower Miyakoan Stage. The Aritan is correlated with the upper part of the Neocomian Stage, the lowermost standard worldwide division of the Cretaceous. The Aritan is characterized by distinctive ammonite cephalopods (mollusks).