Dry Dredgers Field Trip
Saturday, April 27, 2019
Southeast Indiana
Whitewater, Liberty, Waynesville and Arnheim Formations

Photos by Bill Heimbrock
All specimens are to scale with a U.S. penny, diameter 1.9 cm or 3/4 inch.


A good turnout of members and guests

Every year or two we visit our favorite field trip site in southeastern Indiana. Our last visit was October 2017. The site is famous to the the tiny trilobite Flexicalymene retrorsa minuens in the big shale layer of the Liberty Formation. This is presumed to the be the same layer that is exposed at the Caesar Creek spillway.

Fossils Found That Day

Trilobites

Lots of the trilobite Flexicalymene retrorsa retrorsa and F. retrorsa minuens were found. Here are photos of some of them. While reviewing these photos, I spotted an unusual epibont encrusting the right genal area of an enrolled Flexi. Unfortunately, I don't know who found it. If it is you, check your trilobite with a microscope or high-magnification loupe. The attaching animal is a lot more rare than the common trilobite, whatever it is. (next 2 photos)

Check out this interesting underside of a prone Flexicalymene trilobite. The underside components are worth spending time examining because they are not seen as often as the top side. Look for the hypostome or mouth plate which is absent on molts and on this specimen. And what's that tiny blurry granule above the trilobite??? Why it's a very tiny enrolled trilobite! See the second photo for a close-up.

Usually on this particular site we usually find our Flexicalymene trilobites prone or enrolled. Less common are the partially enrolled ones, such as the one below.

Here's a perfect prone Flexicalymene trilobite. The first photo is the top side which was carefully extracted from the shale with all the dirt intact. Prone trilobites are fragile and should be prepared sparingly or not at all onsite. The second photo shows the underside of the trilobite. You can tell a bit more that it's a nice specimen.

The other common trilobite found was Isotelus sp. This first photo is a relatively complete pygidium (tail).

The next two fragments of Isotelus sp. are from the underside of the trilobite and are probably both from the cephalon.

This next one is interesting because on the fragment of Isotelus sp. is a glabella of a Flexicalymene sp. trilobite.

Crinoids

No crinoid calyxes were found and not very many crinoid stems were shown to me to photograph. But someone found a holdfast of a crinoid attached to another crinoid stem. The next 2 photos are of the same specimen.

Nautiloid Cephalopods

This is the only nautiloid specimen shown to me. It's an internal mold of a cephalopod. Note the infills of the individual chambers and at the bottom is a bit of the siphuncle showing.

Coral

Here's a really nice big colony of tabulate coral. (next 2 pics)

Another specimen of a colonial coral found that day.

Although the most common coral we found was horn coral, a solitary coral.

Snails and Monoplacophorans

These two beauties are a monoplacophoran named Phragmolites dyeri.

These next two are internal molds. Perhaps a Cyclonema sp..

Here are two Cyclonema with the shell still preserved. Nice preservation.

This one is Paupospira sp.  

Here's a fragment of Sinuites sp.

Bivalves

Here art the three sides of an internal mold of a clam similar Modiolopsis sp. (next 3 pics).

Brachiopods

Hebertella sp.

The Hebertella on the left is particularly interesting because it has an unusually deep sulcus.

Eochenetes clarksvillensis

Lepidcyclus perlamellosum

Strophomena sp.

Zygospira sp.

Vinlandostrophia clarksvillensis

Glyptorthis insculpta

Plaesiomys subquadratus

On the left is a valve of Plaesiomys subquadratus. On the right is a valve of Glyptorthis insculpta.

Rhynchotrema dentatum

Strophonema sp.

Bryozoans

Alas, a lone bryozoan. Just kidding. They ruled the site.

That's all for this field trip. Now let's see our May 2019 field trip to a huge Kope, Fairview and Bellevue site in Northeastern KY.

See previous field trips to this Southeast Indiana fossil mecca.

October 2017
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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