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
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
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
This pygidium also looks like it might be a Tricopelta breviceps too!
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 Rusophycus. 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. Can you spot the one
trilobite thorax in this rainy picture of fossil hash?
(Clue: it's in the right center portion of the photo above.)
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
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).
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
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.
This first coral is encrusting a strophomenid brachiopod. The coral is
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.
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.
Here's a tiny but nice internal mold of the clam
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.
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