Dry Dredgers Field Trip
April 27, 2013
Southeast Indiana
Waynesville, Liberty and Arnheim Formations

The Dry Dredgers returned to one of their favorite Indiana sites that exposes much of the Richmondian Stage of the Cincinnatian formations. We go in the spring each year because the trilobites weather out with enough rain and freezing/thawing. We always find a decent number of trilobites on this site.

  

Fossils Found That Day

Trilobites

Flexicalymene retrorsa

Flexicalymene retrorsa minuens

Isotelus sp.

A pygidium of the trilobite Ceraurinus icarus.

Crinoids

Gastropods (snails)

 

Corals

Corals were found on this site in two basic forms - solitary and colonial. These next two pictures show a couple of solitary coral named Grewingkia sp..

Another solitary coral we found was Streptelasma sp. Shown below, these corals are sometimes found attached to an object or it is apparent that they were once attached to an object. The picture below is a great example of the latter. These two Streptelasma sp. are now attached to each other and open air, where they were probably once attached to surface of some kind. This is a great specimen!

Here's another fantastic specimen. This brachiopod was PRIME REAL ESTATE for all kinds of attaching creatures. I see at least 5 Streptelasma sp. horn corals attached to it plus I see what looks like a couple of inarticulate brachiopods also attached. Pretty cool.

Now here are some photos of colonial corals.

This first colonial coral is awesome. When first spotted on the ground while the person is standing or walking by, even an expert would think this is a crinoid calyx. It has just the right shape!  But on close examination, it's clearly a group of coral.

A much more common variety of colonial coral we found was this encrusting tabulate coral Protaraea richmondensis. (next 2 pics)

Here's another group of colonial coral. I'm not sure of its identity, but it's interesting how it appears to be mostly below the substrate with the openings keeping a clear path to the water and food.

Pelecypods (bivalves/clams)

Ambonychia sp. (Next 3 pics)

Now here's an interesting bivalve fragment. It's the hinge of what appears to be Cycloconcha sp. preserved in pyrite. Note the "chevron" dentitions.

Brachiopods

It was not very hard to find examples of individual valves of the brachiopod Plaesiomys subquadratus.

Also abundant were Strophomena sp..

Another common brachiopod we found was Hebertella sp..

Large numbers of Cincinnatina sp. (formerly Dalmanella sp and Onniella sp.) were found particularly in the Waynesville Formation on this site.

Here is an interesting fragment of the brachiopod Rafinesquina sp. with a couple of worm tubes, possibly Cornulites sp. attached to it.

There are specific layers on this site where a storm event is apparent by large numbers of the brachiopod Rafinesquina sp. pushed close together sideways.

Mystery Squiggles


The above squiggle is thought to be a cephalopod surface. A previous example of one found on a Dry Dredgers field trip is from May 2006  and also one seen at the March 2009 meeting. However, I also think this surface resembles the monoplacophoran Phragmolites.


Here is another mystery squiggle. It most closely resembles the bivalve Caritodens.

Trace Fossils

That's all for this trip.
Now let's see the May 2013 field trip to Mt. Orab, Ohio.

Previous field trips to this Southeast Indiana fossil Mecca.

April 2012
May 2011

March 2010

September 2008

September 2007
September 2006
March 2006

March 2004

October 2003

April 2002

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