3 min read During the Ordovician period ... known mainly from the tiny fossil teeth they left behind. The few complete fossils that have been found suggest they were finned, eel-like creatures ...

Photomicrographs of local limestone samples below showing fossil fragments (Bc=brachiopod ... section of the Cincinnatian Series limestones (Upper Ordovician) of southwestern Ohio, southeastern ...

Fossil echinoderms, including the common Cambrian and Ordovician echinoderms figured here (Fig. 1 from Deline, et al., 2021; request permission to use here) have a rich and diverse fossil record.