Muds from the emerging Taconic Mountains in the northeast were deposited in shallow tropical seas teeming with abundant sea floor life. Fossils of brachiopods, bryozoans, corals, and crinoids are common in the Ordovician rocks in southwestern Ohio.
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.