The Kaseki Hiroba, or fossil dig site, is a place where fossils of shellfish, plants, and other things from the age of dinosaurs (the late Cretaceous Period) can be collected. The Mifune Group, which is found throughout Mifune Town’s neighboring areas, is a stratum formed in a land and shallow marine environment during the Late Cretaceous Period of the Mesozoic Era, or about 90 million years ago, and has a thickness of as much as about 2000 meters. Due to the different types of rocks that make up the stratum, the Mifune Group is subdivided into three parts: the Basal Formation, the Lower Formation, and the Upper Formation. The Lower Formation of the Mifune Group is exposed at the Kaseki Hiroba and consists mainly of mudstone and sandstone. It is a stratum formed at the time in shallow water and abundantly yields brackish-water and shallow-sea shellfish fossils. On rare occasions, it also produces fossils of terrestrial vertebrates, such as crocodiles and turtles, making this dig site the perfect location to learn about the stratum.
The Mifune Group, which is found throughout Mifune Town’s neighboring areas, is a stratum formed in a land and shallow marine environment during the Late Cretaceous Period of the Mesozoic Era, or about 90 million years ago, and has a thickness of as much as about 2000 meters. Due to the different types of rocks that make up the stratum, the Mifune Group is subdivided into three parts: the Basal Formation, the Lower Formation, and the Upper Formation.
The Lower Formation of the Mifune Group is exposed at the Kaseki Hiroba and consists mainly of mudstone and sandstone. It is a stratum formed at the time in shallow water and abundantly yields brackish-water and shallow-sea shellfish fossils. On rare occasions, it also produces fossils of terrestrial vertebrates, such as crocodiles and turtles, making this dig site the perfect location to learn about the stratum.