Paleontology and geology

Indiana was located south of the equator and was covered by a shallow ocean during most of the Ordovician. The majority of the Ordovician rocks in Indiana are limestones and shales, which are exposed in the southeastern part of the state. These rocks contain abundant fossils of marine organisms, such as brachiopods, bryozoans, trilobites, and corals. Many of the limestones are interpreted as storm deposits.