Ohio's State Fossil - Isotelus
Description From Ohio History Central - http://www.ohiohistorycentral.org/w/Ohio%27s_State_Fossil_-_Isotelus?rec=1874
In 1985, the Ohio government made Isotelus Ohio's official fossil. Isotelus is a trilobite that existed between 430 and 480 million years ago. At this point in time, an ocean covered much of what is now Ohio. Isotelus is evidence of this, as it was a marine organism. A trilobite was an invertebrate creature that had a hard outer shell or skeleton. Two lines crossed the body of the trilobite, making it appear to be in three parts. Trilobite means "three-lobed creature." Isotelus primarily lived during the Ordovician Age. They were one of the largest trilobites, with some of these animals reaching nearly thirty inches in length. Isotelus no longer exist, becoming extinct approximately 430 million years ago.
Isotelus - Ohio's State Fossil
http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/GeoFacts/geof06.pdf
Ohio Trilobites
http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/GeoFacts/geof05.pdf
Fossil Collecting in Ohio
http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/GeoFacts/geof17.pdf
Summary of Geological History in Ohio
http://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/GeoFacts/geof23.pdf
GeoFacts Series Listing by Topic
http://geosurvey.ohiodnr.gov/publications-maps-data/free-downloads/geofacts-series
Two big trilobites have been found in the Caesar Creek Spillway. This one is on display in the Visitor Center. The other one is in the Smithsonian. Photo credit; Erin Shaw - ODNR Caesar Creek Naturalist
Cincinnati Dry Dredgers References
Types of Cincinnatian Trilobites
http://drydredgers.org/trilobit.htm
Videos