Dry Dredgers Field Trip
March 23, 2013
A Creek Bed in Ohio

The Dry Dredgers made their first outdoor field trip of 2013 a repeat visit to the creek bed in Ohio. This site exposes parts of the Maysvillian stage the Cincinnatian. The fossils from this creek are about 445 million years old. They were alive during the late Ordovician Period.

We met at 10 am in a culdesac and proceeded down the trail to the creek. The morning started out being chilly and overcast. But it cleared up later in the morning and became a nice day. Here are some pictures of the site and the fun we had.

Fossils Found That Day

The best find of the day was probably this double specimen of the trilobite Flexicalymene meeki. Very nice. It's unusual to find two prone trilobites beautifully preserved on one rock from a creek bead.

Photo courtesy of Steve Mccabe

And in true style of traditional paleontology, one of our younger, artistic members was able to provide us with an illustration of the above specimens, ready for publication in a professional journal!

Now, after a professional preparation job, here is the dual specimen all cleaned up. Don't it clean up nice?

The double-trilobite specimen was found weathered out of the bluish colored "butter shale" layer exposed on the bank of the creek.  (next 2 pics - courtesy of Steve Mccabe)

Here are some pictures of other Flexicalymene meeki found on the site that day. The second photo is a Flexi that is inverted (upside-down) in the shale.

Trilobite: Isotelus

Only fragments of the trilobite Isotelus were found, but as you can see from the photos below, they are nice fragments.

Pelecypods (Clams or Bivalves)

This site was loaded with moulds and casts of clams. Some were larger than the common Ambonychia. I think those are Anomalodonta plicata, as shown in the next two pictures. The first picture uses a finger for scale.

In this next picture, we see a slab was found that not only has an Ambonychia sp. and an Anomalodonta sp., but it looks like it also has an ENROLLED FLEXICALYMENE TRILOBITE! (Do you see it?)

Here are a couple more photos of clams that are likely to be mostly Ambonychia sp..

There were also clams with a black film material. These "black clams" are probably Modiolopsis sp.  This black film often has relict microstructure that reveals shell features not seen without a Scanning Electron Microscope (SEM).

Cephalopods

As was true in other visits to this site, a large number of straight-shelled nautiloid cephalopods were found.

Gastropods (snails)

Most of the snails found were internal moulds, such as the one below.

 

But good quantities of the platyceratoid gastropod Cyclonema sp. were also found. These snails have shell features preserved, which is typical for Cyclonema.

Brachiopods

Brachiopod: Vinlandostrophia ponderosa

Brachiopod: Zygospira modesta

Brachiopod: Rafinesquina ponderosa

Bryozoans

Ichnofossils (trace fossils)

Non-Maysvillian Fossils

Recent animals

Now let's see the April 2013 field trip to Southwest Indiana.


See previous trips to this creek bed in Ohio

2010
2009

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