The Precambrian: The Precambrian in Indiana is represented primarily by igneous rocks, thus there are no Precambrian fossils known from the state. These igneous rocks are not exposed at the surface anywhere in the state and are known only from drill cores.ield Guides (showing 3 of 3 listings). Cincinnati Fossils: This site lists all fossil taxa described or reported from the type Cincinnatian strata (Upper Ordovician) of Ohio, Kentucky, and Indiana, including mollusks, arthropods, echinoderms, brachiopods, and many other groups.