The first field trip of the season is always a good one. The winter brought a miserable February with lots of freezes and thaws that break up rock and expose fossils. It was a great February for fossil hunters to enjoy in March. It was a beautiful early spring day with plenty of sun. So the turn-out was the best ever, with more than 50 people attending. As you can see from these pictures, there is plenty of room on the site for everyone and a plethora of fossils. As our field trip chair, Bob Bross, phrased it at the meeting the night before, "the site is fossiliferous. That means lots of fossils." He was right.
The chosen site was a large road cut in southeast Indiana that is very popular with colleges and fossil clubs for field trips. It exposes the Waynesville, Liberty and Whitewater formations of the Richmondian stage of the Cincinnatian Series. The age of the rocks is approx 430 to 440 million years old.
Here are some photos of the great time we had.
Best Finds of the Day
There were many good finds that day. I think the best was a Tricopelta breviceps (formerly Chasmops breviceps) Trilobite. Shown in the four photos below, it is not whole, but there are signs that there are actually two specimens of Tricopelta in this one specimen. Note in the second picture below how you can see three compound eyes, two of the articulated above the Glabella and one below the Glabella. Very nice find!
I think the next best find is this crinoid calyx.
It appears to be a Cupulocrinus
polydactylus, but missing the basal plates.
Photo Courtesy of Cynthia Striley
Next in the "best find" category are two Cephalopod
entries. The first shown below is an impression of the surface of a Cephalopod.
I think the impression was made by bryozoans that were attached to the Nautiloid.
The next best was this curved or coiled Cephalopod.
Also in the best find category is what I think is either the
But I'm not sure which. Graptodicta are
typically from the Farview formation, which makes me uncertain. You be the judge. It's an interesting
specimen, in any case.
Another good find was the Monoplacophoran, known as Phragmolites
Here are the rest of the finds that day.
Trilobites Found: Flexicalymene retrorsa
This is one of our best sites to find trilobites. The most common of these is the Flexicalymene retrorsa.
The next two specimens are the burrows known as Rusophycus
of trilobite Flexicalymene.
Trilobites Found: Isotelus
A nice pygidium (tail plate) of Isotelus was
And also found was a genal spine.
A young member found a nice Grewingkia.
Streptelasma, which are smaller and are
attaching solitary coral, were also found.
Streptelasma Horn Coral
The Streptelasma can be distinguished from Grewingkia
by a smaller size, wider opening and a narrow end that shows it attached
to an object.
Another type of coral that was found is not a solitary coral
but a colonial coral that encrusts brachiopods and other hard shells. Here is an
example of the coral Protaraea richmondensis encrusting the
Here is another example of a colonial coral. Note the septa on
the sides of each chamber.
It was easy to find articulated crinoid stem sections on the
surface of rocks (next 2 pics).
Most of the Gastropods found that day were internal molds with
no external shell featuers. (next 3 pics.)
Some gastropods, though, did show external features and were
preserved in Calcite.
Another type of mollusk found was this Bellerophontid Monoplacophoran.
The most common kind of Articulate Brachiopod found that day
In some layers, the Rafinesquina were
"shingled" and compacted in a slab of rock, probably as the result of
a storm event 445 million years ago.
The next most common Brach is similar to the Rafinesquina. It's Strophomena. (next 2 pics)
This site is rich for it's variety of Brachiopods. This
includes the common Articulate Brachiopod genus, Lepidocyclus.
(next 3 pics)
The Brachiopod Hebertella
could also be found here and there. (next 5 pics).
People also found examples of Glyptorthis.
One type of Brachiopod found here is similar to the Sowerbyella
of the Kope Formation. Here in the Richmondian, though, we find Eochonetes,
Here are some inarticulate brachiopods called Petrocrania
scabiosa, attaching to a Rafinesquina, a type of articulate brachiopod.
Quite a few different kinds of clams were found. Most were
internal molds. One type, however, was commonly found with the external surface
features of the shell preserved. The clam is named Caritodens
Another genera of clam, Ambonycha, also had
surface features, not so completely preserved, but visible.
The internal molds could be identified, at least as clams, by
the presence of a hinge line where it was clear there were two separate, but
equal valves. (next 2 pics)
Here's a group shot showing a Caritodens alongside two
internal molds. Note that black coloring on one. This is of particular interest
in that it's a remnant of the original shell.
Among the Bryozoans that could be easily identified was
Constellaria. It's identified by the star patterns on it's surface. Thus the
There were plenty of ramose (branching) Bryozoan pieces found.
Other Bryozoans found had a flat, "leafey" shape.
Many fossils and rocks revealed beautiful Calcite crystals on
the inside of them. These are the the carbonates from which many our rocks and
fossils in the greater Cincinnati area are made.
There were plenty of good examples of straight shelled
nautiloid cephalopods found. These are often prized finds when they are large,
articulated or well preserved.
Above and below photo courtesy of Betty Yan.
The above is a group shot of one member's finds. Can you now identify everything in the picture from the previous ID's in this field trip report?
Another cephalopod that was found was this fine and rare type of curved cephalopod. I did not see this specimen but Greg Courtney caught it on video. See the video of this field trip from our education chair, Greg Courtney, on Youtube.
Meet our education chair, Greg Courtney, and see all his videos on on Youtube.
That's all for this month. Join us for our April field trip to Northern Kentucky.
See photos of previous field trips to this Southeast Indiana fossil meca.
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