Dry Dredgers Field Trip
May 29, 2010
Caesar Creek Spillway, Ohio
Liberty and Lower Whitewater Formations

We had a relatively small turn-out for our field trip the famous Caesar Creek Ohio spillway field trip. We had not been there since April of 2000. I think many Dry Dredgers think that all the good fossils are picked up and nothing new has eroded out. I've heard claims that mud continues to cover the site over time. The few Dry Dredgers that attended did not have problems with those issues. Good fossil hunters can find good fossils.

If you are going to Caesar Creek to fossil hunt, you need to go to the Visitor Center and sign a permit that allows you to collect in the spillway of the Dam. The spillway is the only place where fossil hunting is permitted. So we first met at the Visitor Center, signed our forms and then proceeded to the spillway to collect fossils

I highly recommend the visitor center. It has a really nice, but small museum of the fossils that have been found at Caesar Creek. Included are specimens from the well known Tom Johnson as well as Dry Dredgers members, such as Ron Fine.

Here are some pics of the visitor center. Don't forget, you must come here and get your permit before fossil hunting.

At the spillway, we gathered and made our way to the flat area of the spillway.

The Caesar Creek spillway has a well illustrated sign describing what you will find on the spillway floor, which was the ocean floor 450 million years ago during the late Ordovician period.

Here are some photos of us collecting fossils in the spillway.

Best Fossil Finds of the Day

Perhaps the best find of the day was this crinoid calyx (head) of Cupulocrinus polydactylus. (next 3 pics)

The next best find, I think, was this head of the trilobite Tricopelta breviceps, showing the excellent compound eye.

And since Caesar Creek is famous for it's trilobites, quite a few enrolled Isotelus trilobites were found, although they were all tiny as the photos show (next 5 pics).

These small Isotelus were also evident in the trace fossils they left on the surface of the ocean floor. This one below terminates with the resting trace of the Isotelus, called Rusophycus. Note from the picture that the trace fossil is from a small trilobite, typical of Caesar Creek and the fossil fits in the palm of the hand, which is the largest size permitted by the Army Corps of Engineers to be collected and taken home from the spillway.

Isotelus fragments were also common throughout the spillway. This is the way most people find Isotelus trilobites in the Cincinnati area. (next 2 pics)

Trilobite: Flexicalymene retrorsa minuens

Flexicalymene Trilobite Burrows: Rusophycus

We did find colonial coral on the spillway floor. It was a large rock too big to take back, since the limit is fossils the size of your hand. The specimen below is a big rock comprised entirely of the coral Tetradium.

Another type of coral found was solitary coral (horn coral), such as this specimen of what appears to be Streptelasma.

We also found evidence of crinoids. Here is a really nice cluster of crinoid holdfasts. This plated form of holdfast is called Lichenocrinus. These specimens were attached to a brachiopod named Rafinesquina.

Quite a fair number of straight shelled nautiloid cephalopods were found. Here are some internal molds (next 3 pics.)

Among the trace fossils found were worm burrows on the surface of rocks.

Internal molds of gastropods (snails) were found.

And also internal molds of pelecypods (snails) were found. The one below has a bit of dark calcification that preserves some shell features. It looks like it could be the clam Ambonychia.

Here's a nice assortment of fossils one Dry Dredger found at Caesar Creek that day. It gives you an idea of the relative quantities of each fossil type.

Now see photos of our July 2010 field trip to Bardstown, KY with the KPS and a picnic.

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