Geology of Clermont

& Vicinity

Clermont County is situated in a unique Geologic region. We have Ordovician bedrock rich with fossils and an interesting Glacial past that has shaped the area where the County resides.

The Ice Age

Glaciers flattened, eroded, and shaped the region.


Geologic Time

Why Clermont County and South Western Ohio's bedrock is special.
The geologic time scale is a linear timeline throughout Earth's history. It subdivides all time into named units eons, eras, periods, epochs, and ages. This is an illustration of the full geologic timeline.
All of Clermont County lies within what is called the Cincinnati Arch and Cincinnati Anticline, which has given the area a unique exposed alternating limestone & shale bedrock. The fossiliferous Ordovician strata have been exposed in our surrounding counties, and all strata between the Ordovician to the Pleistocene have been either eroded away or not been deposited over the millions of years, giving us our unique fossils and limestone strata you see in roadside hill cuts, landslides, rivers, and streams. This illustration represents the missing rock strata that eroded over time.
Clermont's Ordovician bedrock was created when the land we now call the State of Ohio was within a shallow ocean and was located below the equator.
The Ordovician oceans were full of life, some being algae, bi-valves, brachiopods, cephalopods, crinoids, trilobites, corals, and many more.
Over time these creatures died and landed on the ocean floor, accumulating and being covered by layers of shells and fine silt. It is thought extremely violent hurricanes would pull sediment and mud from shallow regions and lay that sediment as layers over the ocean floor which would become today our shale layers. The previously mentioned shell deposits would become limestone. The shell layers (future limestone) would take long periods of time to accumulate, while the mud silt layers (Shale) could happen in a short period of time, covering the sea life and giving us the intact fossils between the shale and on top of the limestone.


Road cuts throughout the county and area expose the strata of fossil-rich Ordovician rock structures.


With the help of amateur and professional paleontologists, and rock hounds we hope to expand our fossil section at the moment I have put together a list of fossil scientific names of the area fossils.

Fossils Gallery is under construction