The Kitadani Formation (Japanese: 北谷層 Kitadani-sō) is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum.
The Kitadani Formation is a unit within the Tetori Group, a major sequence of Lower Cretaceous rocks that is distributed across Fukui, Ishikawa, and Gifu prefectures of western-central Honshu. The Tetori Group exhibits marked lateral variation, and the Kitadani Formation is only present in Fukui Prefecture. The Kitadani Formation comprises interbedded tuffs, sandstones, and shales and reaches a maximum thickness of approximately one hundred meters (~328 feet). It conformably overlies the Akaiwa Formation and is unconformably overlain by the Omichidani Formation. The Kitadani Formation is significant because it is the major source of dinosaur fossils in Japan and because of Japan's unique position along the northeastern margin of Eurasia during the Early Cretaceous.
