Fossils 101: Caesar’s Creek Ordovician Fossil Hunting

When I was a child growing up in Ohio, my class would take yearly fieldtrips to the Caesar’s Creek Spill off to go fossil hunting. As a child, it was hard to stay focused on the task at hand. We would never read the signs stating we had to leave behind the fossils bigger than our palms, and now that I’m older, I can appreciate why the signs were posted.

I was lucky enough to find a sample of every fossil that ever lived in this area. Rather the fossils that archaeologists are aware of. Some of them are quite small and some are broken in pieces, nonetheless, I was lucky to find the samples that I did.

What is a fossil?

For those of you fossil novices, a fossil is formed when sea creatures die. Their bodies would float to the bottom of the sea. As with most fossils, if the animal was covered quickly with mud and silt, like many dinosaurs were, its hard outer coating or shell would be protected from deterioration and rotting. After years and years of weathering and layers upon layers of mud and other animals, the weight of the mud became so heavy that it turned to stone, and the animals to fossils.

Ordovician Fossil Hunting

My personal trip to Caesar’s Creek to find fossils.

This particular area was the home of the Ordovician Sea, a warm, shallow sea, dating to around 450 million years ago during the Ordovician Period.The name Ordovician came from the British tribe called the Celts who lived near the area these fossils were found, and are still being found. Interestingly enough, the fossils formed long before the Celts were born.

Trilobites

The most fascinating of the fossils found here, and it’s quite rare and hard to find them in fact, are trilobites. Trilobites were close relatives to the horseshoe crab and they had a three lobe body which they could curl up like a pill bug to avoid danger. Trilobites were related to modern day spiders, lobsters, insects, and crabs and they crawled on the ocean floor, where they shed their hard outer covering.

Although trilobites lived in the ocean 35 time longer than humans have lived on earth, they became extinct close to 250 million years ago. No one seems to know why, however fossil hunters have a healthy obsession with finding their remains.

Horn Coral

If you searched the ocean floor over 400 million years ago, beneath the mud you would have found these horn coral attached. These fossils look like a dinosaur’s tooth or a bull’s horn, although they really were ancient sea creatures.

Cephalopod

The cephalopods were related to the Octopus Family, however they have a cone-shaped shell, similar to an ice cream cone. The shell covered the entire body and only its head and arms stuck out. These sea creatures would fill their chambers with air and then propel themselves by shooting the water back out, thrusting them forward.

Bryozoan

The Bryozoan may look like coral, however they were animals which built homes around themselves, resembling twigs of a tree. These fossils, also called “moss animals”, were the apartment builders of the ocean floor.

Gastropod

The Gastropod fossil is located at the bottom left of this sample where the rock narrows, and its looks like a spiral shaped shell. There is also a crinoid sample at the far right on the bottom (looks like a tootsie roll).

When I first found a Gastropod fossil it looked more like a modern snail and that’s exactly what these ancient sea creatures really looked like. These snails carried their homes on their backs and moved by using a muscular foot.

Crinoid

The quartz looking animal you see to the far left is actually a top to a crinoid.



I found several crinoid samples, yet they were missing many of their stems. Crinoids were called “sea lilies” and they had a stem which attached them to the bottom of the ocean. Some would actually float in the ocean. Typically, the center of the crinoid had a five point star in the center of the stem, at the bottom usually. The Crinoid was related to the starfish.

Brachiopods

I had so much luck finding Brachiopods. In fact, I found one that had separated from a very large piece of limestone. Separated in way which made me think someone chiseled it out.

Brachiopods resemble sea shells which is why people tend to throw then back on the pile. Not to mention, they are the easiest fossils to find at Caesar’s Creek. Many of these creatures could be found on the bottom of the Ordovician Sea, attached by a small foot. Some were drifting about and some burrowed in the mud. Most of the specimens I discovered were attached to a large piece of limestone at the bottom of the spillway.

More Video Footage of Caesar’s Creek Fossils

This is a delightful video a couple took while on a day trip to Caesar’s Creek. Keep in mind, however, that climbing on the rocks is strictly prohibited. Visitors are encouraged to stay at the bottom of the spillway so not to destroy any layers of the limestone and the fossils they preserve.

What’s your fossil hunting memory? Did you have a place like this in your hometown?

Also check out:

Ohio Decalogue Stone

How odd to find out that a rare tablet was discovered not far from where I used to live in Ohio. The Ohio Decalogue Stone, sometimes called the Ten Commandment Stone, was discovered in Ohio by archaeologists during the excavation of a cairn in 1860.

Read more: The Ohio Decalogue Stone

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