The weather held out for the Dry Dredgers that overcast spring morning. There had been plenty of rain, but none that day. March field trips are often "iffy", but the Dry Dredgers hold their field trips rain or shine.
The site we chose for the day was one that has been popular for decades, particularly in the spring, when the winter's freeze and thaws break down the shale into clay and expose high quality fossils of all kinds. The layers exposed are from the Kope (Latonia) Formation. So they are mostly shale, or mudstones, with occasional cycles of hard limestone rock the pros call carbonate facies. The site showed us most of the Southgate member of the Kope. I love the Southgate. We have had so much fun over the years collecting on these northern Kentucky road cuts. I hope the photos give you an idea of how we enjoy being out here.
Pictures of the site:
Fossils Found that day:
Best Find of the Day
The best find today was a nice piece of what I think is
colonial coral from the Kope Formation. Coral is rare, or at least uncommon, in
the Kope. Almost all the reef building animals were Bryozoans 450 Million Years
ago in our area. I'm not completely certain this is coral, though. The openings
have weak or no septa. (See second photo). In the Cincinnatian, unlike in the
Lexington layers to the south of us, the preservation is much better. There is
very little crystalization and mineralization. In any case, this is a great
The next great find by a young member. It's Bryozoan with borings of Catellocaula vallata.
This is thought to be a tunicate. It is bored into a Prasapora simulatrix
Bryozoan. (next 2 photos).
No examples of the usual crinoid Cincinnaticrinus varibrachialus were found. They are probably more common than the ones we did find, but are smaller and harder to see.
It was also foretold at the meeting the night before that many
Nautiloid Cephalopods would be found. They were right. And the shell
preservation on many of these is excellent!.
Above photo by Marianne Shelton
While other Flexicalymene's were found as molted parts. Here's a pygidium (tail) in matrix (rock).
No whole Isotelus were found, but quite a few hypostomes (mouth plates) were found. (next 3
photo by Marianne Shelton
The shale layers of the Kope formation are not always
homogenous units of hard clay. There are often pockets of nodules, usually below
limestone layers. On some of these nodules, you can see encrusters like
bryozoans and crinoids. In the two examples below, no encrusters were found, but
the color of the nodules has changed and there may be surface evidence that
encrusters had been weathered off these specimens.
Some bryozoans we found had what appeared to be borings in them, such as the next specimen. It's possible this is Catellocaula vallata.
A wide variety of bryozoans could be found on this site. The
one in the center of the next photo is
Worm Tubes Found
The tubes of annelid worms such as Cornulites were found loose on on rock surfaces, as shown in the next two photos. When found in rocks, they do not always show that in life their narrow end was attached to something. Occasionally, we find what may actually be a free-swimming animal, known as Tentaculites. The true nature of the animals that made the fossils Cornulites and Tentaculites are still being investigated and can still be considered problematica.
Trace Fossils Found (Ichnofossils)
That's it for March 2009. Now lets look at April's field trip when the Dry Dredgers return to the Ohio Ponderosa Ranch.
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