Abstract
Large-sized stegodontid left and right fossil molars were discovered during dam construction for a storage reservoir in Hirayama, Ajimu-machi, Usa District, Oita Prefecture in February 1987. Subsequently, an excavation of the locality was undertaken in November 2004 by the Lake Biwa Museum, Ajimu-machi Board of Education, and local volunteers. The skull of the molars was discovered in the middle part of the Tsubusagawa Formation, but unfortunately, due to strong compression in the bed, its form could not be observed in detail. The presence of nine ridges and a talon in the fossil molars indicates that they are from Stegodon miensis.
