Dry Dredgers Field Trip
March 28, 2015

Southeast Indiana
Waynesville, Liberty and Arnheim Formations

Photos and words by Bill Heimbrock

It was below freezing that morning when we arrived at our favorite fossil site - a large road cut that exposes almost the entire Richmondian Stage of the Cincinnatian Series of formations. We had a huge turnout of members that morning. It was so cold, the mud was frozen and picking up fossils on the surface was like the old penny glued to the sidewalk trick. But that didn't stop anyone from collecting fossils.

We started on the sunny side of the road and the ice turned to mud. We were glad for that. By afternoon, the other side of the road had melted too, making some great fossil hunting.

- - Fossils Found That Day - -

Best Finds of the Day: The Mollusca

I heard one person say that they thought everyone looking for trilobites found at least one. That is probably true, but the best find of the day was this large coiled nautiloid cephalopod that appears to be Charactoceras baeri. It was found in the talus from the base of the Lower Whitewater formation. It's a really nice specimen, but began crumbling when handled. It's still in good shape, though. (next 3 pictures)

Most of the nautiloid cephalopods we found that day were straight shelled. Here's both sides of one nice specimen.

Here's another straight shelled nautiloid that was falling apart. What remains are the internal mold of each chamber of the orthocone.

Individual fragments of nautiloid cephalopods were fairly common as shown in the random sampling below.

The next best find of the day was this very strange bryozoan. It appears to have encrusted something that is completely gone now, but the original shape of the outer shell is preserved. Our best guess at this time is that it was a monoplacophoran called Cyrtolites ornatus. it was originally encrusted with bryozoans, as are many Cyrtolites, but the shell did not survive. We now see only the bryozoan taking its shape. Very interesting (next 2 pics).

Monoplacophorans are thought to be a type of mollusk. Here is another monoplacophoran found that day. It's Phragmolites dyeri. Note the ornate surface.

A similar form that was found is more likely to be a snail. It most closely resembles Trochonema madisonense

More common were the spired snails like the two pictured below.

Pelecypods (clams)

Another type of mollusk we found was pelecypods - specifically the internal molds created by clam shells. Here's a picture of one showing the hinge line to prove that it's really a clam.



This site may be the best public site in the Cincinnatian for finding trilobites. Most people found their trilobites in the butter shale layer of the Liberty formation. One person found at least 6 Flexicalymene sp. trilobites. (next 3 pics)

Most people found only one trilobite, though. Here are some of the Flexicalymene sp. found.

The above picture shows only the glabella of a Flexicalymene on a rock surface.

But this next one is pretty interesting. It looks like a burrow of a trilobite. But it also resembles the form of a nautiloid cephalopod which shows the siphuncle.

Some Isotelus trilobite fragments were found too. Here's a huge but nearly complete hypostome (mouth plate) of what was clearly a large Isotelus sp.

Some thorax segments of broken Isotelus were still articulated.

Also, the Isotelus shell segment form the genal area were found loose and in matrix (next 2 pics).


This Indiana site is rich in brachiopods. You can collect more than a dozen varieties from this site alone if you try.

First we have examples of Lepidocyclus perlamellosum. Some of these could actually be Hiscobeccus capax.

We also found some individual valves of the brachiopod Plaesiomys subquadratus.

We all found lots of Strophomena sp..Note the identifiable muscle scar in the second picture below.

Strophomena sp. were found covering many of the slabs of rock in certain layers of this site.(next 2 pics)

Only a few Glyptorthis insculpta were found. Here are photos of the two valves of one nice specimen we found.

This next brachiopod, I'm not sure of the ID. I'll update my report as soon as I find out for sure. It looks like a Cincinnetina sp..

This next brachiopod is easy to identify. Rafinesquina sp. are common throughout most of the Cincinnatian and this site was no exception.


This next Rafinesquina specimen has two different kinds of inarticulate brachiopods attached to it. As seen in the first picture, the larger scab-like mass is Petrocrania scabiosa. In the second picture, we see the other type of inarticulate - Philhedra sp..

In pockets of shale, we found bunches of the small brachiopod, Eochonetes clarksvillensis. These were formerly referred to Thaerodonta.

And no trip to a Richmondian fossil site is complete without finding at least one Hebertella sp..

Here's a sample of rock showing the huge variety of brachiopods that are everywhere on this site.


Two basic types of coral were found on this site in the Liberty formation. Rugose solitary coral (also known as horn coral) and colonial coral.

The most common horn coral we found was Grewingkia canadensis. (next 7 pics).

The common colonial coral we found was Protaraea richmondensis (next 3 pics).


Like all Cincinnatian fossil sites, bryozoans were everywhere. Here is one rock with some attractive specimens of ramose (branching) bryozoans.

Ichnofossils (Trace Fossils)

Most of the trace fossils we found seemed to be presumably worm burrows. Here's one in which the burrows seem to go in multiple dimensions in the rock.

And finally, here are some of the collecting bags people had to show with their various selections of fossils. The Dry Dredgers stir up quite a bit of controversy over whether to use plastic bags, cloth bags, buckets, baskets, or coffee cans in which to collect fossils. Here is some evidence that plastic bags are popular.

That's it for this field trip.

Now lets see how we did on our April 2015 field trip to a Northern Kentucky Kope Formation Site.

See previous field trips to this Southeast Indiana fossil mecca.

March 2014
April 2013
April 2012
May 2011

March 2010

September 2008

September 2007
September 2006
March 2006

March 2004

October 2003

April 2002


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