Dry Dredgers Field Trip
October 28, 2017
Southeast Indiana
Whitewater, Liberty, Waynesville and Arnheim Formations

Photos by Bill Heimbrock

A cold rainy evening at the Dry Dredgers meeting was followed by a cold rainy start to the next day as the Dry Dredgers packed up to head out on the 10 am October field trip to a Southeast Indiana road cut.  The sky became partly sunny and warmer by 9:45 am and for most of the field trip, it was pleasant fossil hunting conditions. More than 10 people showed up for the trip. There was no rain and only late arriving chilling winds.

This site, which we last visited in March 2016, exposes most of the Richmondian Stage. Today, we will be spending most of our time finding tiny trilobites in the Liberty Formation of the Richmondian.

Here's Bill Heimbrock, who lead this field trip, at exactly 10 am waiting for people to arrive.

People did arrive, although they waited to make sure it wasn't going to start raining again. Some great fossils were found. Here are some photos of us collecting them.

And there's Steve Felton, our most advanced amateur who has won many awards for his outstanding contributions to the science of paleontology.

And what's up with this? Someone has tied a solar light to a telephone poll that sits on the first shelf of the Liberty Formation trilobite layer. Are they a night-time fossil hunter?

Fossils Found That Day

Best Finds of the Day: Trilobites

Tricopelta breviceps

Mike Bahan found this rare trilobite in the trilobite layer of the Liberty Formation, but didn't realize what he had found until he got home and examined it more closely. The thorax (middle) and pygidium (tail) look a lot like a Flexicalymene. But this one is special. It has a compound eye and a broad nose. It's a Tricopelta breviceps! Several others have been found by Dry Dredgers members in the past. Compare that to the thousands of Flexicalymene that have come out of that trilobite shale layer in the past. Nice find Mike! And thanks for the photos. 

Photo by Mike Bahan

Mike also found a double Rusophycus (trilobite burrows) with an enrolled trilobite on the underside!!! Did this trilobite make this burrow? Probably not. The trilobite is enrolled and at a 90 degree angle to the husophycus. But it's exciting to find anyway.

Photo by Mike Bahan

Trilobite Flexicalymene sp.

A Fist-full of Flexicalymene retrorsa minuens found by one family. This is the largest number of trilobites found by one family that day, I think.

The prone trilobite in this group had an enrolled Flexicalymene trilobite inside it! That really makes a total of six trilobites.

Here are some of the individual Flexicalymene retrorsa minuens found that day.

And lots of Flexi parts were found too. (next 2 photos)

Isotelus sp. Trilobite Parts

Isotelus trilobites can get up to 2 feet long or more. But as is true everywhere in the Cincinnatian, we find only fragments on this site.

Here are a couple of partial genal spines of Isotelus sp. we found that day.

We also found nice big thorax segments of Isotelus. (next 2 pics)

And here's a nice pygydium (tail) of an Isotelus trilobite. This was a big trilobite when it was alive in the late Ordovician Period (440 Million years ago).

Brachiopods

The most abundant brachiopod we found in the Liberty formation was Strophomena planumbona. Here are the two sides of this brachiopod, the brachial valve and the pedicle valve, respectively.

Lots of the partial Strophomena planumbona were also found showing the muscle scars on the inside surfaces.(next 2 pics)

The next most abundant brachiopod was Rhynchonelld brachiopods - Lepidocyclus perlamellosum and Hiscobeccus capax. (next 2 pics)

The trilobites in the Liberty "big shale" that day were mixed in with a tiny brachiopod that is the same size and similar shape, making the trilobites more difficult to find. These next 2 photos show Zygospira sp. brachiopods in wet shale that resembles the scene of an Ordovician sea bottom. In this way, we are traveling back in time.

Corals

This first coral is encrusting a strophomenid brachiopod. The coral is Protaraea richmondensis.

We found lots of horn corals. These are solitary corals in which the tip rested in the mud and the wide end is where the animal fed. The specimens in the next 3 photos look like Grewingkia canadensis.

Crinoids

We didn't find any crinoid calyxes (heads). But we did find lots and lots of stems. Here are a few pieces in the next 2 photos.

Pelecypods (clams)

Here's a tiny but nice internal mold of the clam Lyrodesma sp.

Gastropods (snails)

These next 2 pics look like Paupospira sp. internal molds. There are layers on this site that are loaded with snails. Somewhat like other snail-rich layers in the Cincinnatian, including the Miamitown Shale Lagerstatten.

That's all for this trip. Thanks for coming!

See previous field trips to this Southeast Indiana fossil mecca.

March 2016
March 2015
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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