Dry Dredgers Field Trip
April
26, 2014
Northern Kentucky Scenic Byway
Middle Kope to Lower Fairview Formations

Photos and words by Bill Heimbrock

The Dry Dredgers had a dry and pleasant day for the April field trip, which was in contrast to the drizzly day we had for our March field trip.

This month we returned for a tour of some road cuts along a scenic byway in Northern Kentucky. Gas prices were up to $3.89 per US gallon (which is high for us), so stops were chosen that were close to Cincinnati. 

Site 1

Our first stop was to a site that exposes the lower Fairview Formation and the upper Kope formation. These rocks are about 450 million years old. The fossils are from animals of the Late Ordovician Period, a time when a shallow sea covered this part of the continent, which was then near and below the equator, making it a tropical paradise of marine invertebrates.

Here are some photos of the nice spring day we had and the Dry Dredgers doing their thing, surface collecting nicely preserved and abundant fossils.

Fossils Found that day: Site 1 (Lower Fairview/Upper Kope Formations)

Cephalopods 

Almost immediately after stepping out of the car, we found examples of huge straight-shelled nautiloid cephalopods in the upper Kope slabs.

Lots of other straight-shelled nautiloids were found at site 1 preserved as internal molds and/or calcite replacements. This next photo shows a cross-section of a siphuncle, which is a tube that runs along the internal length of the orthocone.

This next example is odd because it's a bit disarticulated. It looks like a crinoid stem, but the chambers of the cephalopod replaced with calcite can be seen.

You can see this same preservation in these next two specimens of cephalopods.

We also came across cephalopods that were filled in with shale and fossil hash.

Here is a real puzzler. I have heard that the bryozoan Spatiopora sp. which encrust nautiloid cephalopods align their monticules in the direction of the cephalopods travel, perhaps to reduce water resistance. That makes sense, right?

Here's a cephalopod specimen found at site#1 that's encrusted on both sides with Spatiopora sp..One of those sides (second picture below) is a partial cast of the cephalopod shell, with Spatiopora sp. encrusting the inside structure and the monticules are still aligned in the direction of travel. How can this happen? The cephalopod was dead when the shell was partially filled in with silt. Did the bryozoan encrusted the silty cast of the shell? Or was the bryozoan on originally on the outside surface of the cephalopod shell when the animal was alive and continued to encrust the cast after the cephalopod was dead and the shell disintegrated? Send your thoughts to Bill Heimbrock at billheim@cinci.rr.com.)

Crinoids

In several spots there were pockets of crinoid stems but no other body parts of the crinoid, such as the calyx (cup) were found. The species is hard to identify from the stem, but thanks to resources such as Jack Kallmeyer's and Ron Fine's Crinoid stem web page,  it is possible. The stems below are likely to be Cincinnaticrinus varibrachialus and Ectenocrinus simplex. Both of these are common in the Kope and Fairview Formations.

Trilobites

Probably the best trilobite found at site #1 was this inverted exoskeleton of a Flexicalymene sp. (next 2 pics). This could be of the species F. granulosa or F. meeki. It's probably a molt because the thorax segments look like they have separated and the hypostoma (mouth plate) is missing. But the free cheek is broken rather than separated along the suture, as is happens when Flexis molt. So I'm not certain in this case.

This ichnofossil (trace fossil) may be the tracks/burrow of a trilobite, possible a Flexicalymene. There are signs of foot marks moving in the mud.

Most often, fragments of Flexicalymene species are found on the surface of rocks and shale. Can you identify the Flexicalymene parts in this photo (below)?

The other trilobite we found parts of was the very large Isotelus sp.. In the photo below, we found a large fragment of either the cephalon (head) or the pygidium (tail).

Bryozoans

As is true for almost all fossil sites in the Cincinnati Ohio, Northern Kentucky and Southeast Indiana region, bryozoans are abundant. But one particular type of bryozoan is limited to the Fairview formation and we found quite a few examples of it. I'm referring to Escharopora falciformis.   (next 3 photos)

Other than that species, the brozoans we found were hugely abundant on site 1.   We found some massive trepostomate bryozoans...

And we found lots and lots of ramose (branching) bryozoans. (remaining photos)

 

Brachiopods 

The most common brachiopod we found at the Fairview and upper Kope formation site #1 was Cincinnatina multisecta (formerly Dalmanella multisecta and Onniella multisecta).

Gastropods (snails)

The only gastropod I saw that day on site 1 was this example of Paupospira bowdeni.

Graptolites

Yes, we even found graptolites, thanks to Dry Dredgers vice president, Rich Fuches.

Ichnofossils (trace fossils)

Trace fossils abounded on site 1.  This first one is a bit of a mystery. These burrows are denser than the surrounding shale, allowing them to come above the eroded surface of this slab.

An interesting and common trace fossil we found were Diplocraterion. These are "U" shaped burrows that look like dumbells on the surface, having a bulge at either end (first picture). From the side of the rock, you can see that the burrows go vertically down into the substrate and form a "U" shape.

The site had lots of other trace fossils on shale surfaces.

Stromatoporoid?

I'm not sure of the identification of this fossil. It looks like a bryozoan, but it could be a stromatoporoid, which are currently thought to be sponges.

Site 2

The second stop was to a site that is described as an exposure of the middle Kope formation.

Fossils Found that day: Site 2 (Middle Kope Formation)

Site 2: Cephalopods

As the pictures below show, there was some excellent brown calcite internal molds of straight-shelled nautiloid cephalopods.

Site 2: Bryozoans

Oddly enough, we found several spear-shaped bryozoans with diamond-shaped zoecia we recognized as Escarapora sp.. But I would guess the species is probably Escharopora acuminata because it was found in the middle Kope rather than the Fairview formation. 

Other bryozoans found include massive bryozoan structures.

There were some "leafy" trepostomate bryozoans found.

And branching (ramose) bryozoans were abundant.

Site 2: Crinoids

 

Here's an interesting crinoid stem. It's grouped with some similar-looking bryozoans. Can you spot the crinoid stem in the next photo? I think this is Anomalocrinus sp., which frequently keeps company with bryozoans.

Here are a couple of pictures of the holdfast of the crinoid Anomalocrinus sp. It attaches to bryozoans and often has a shape like a "volcano."

This next crinoid stem is also very interesting. It's highly weathered and looking at it edge-on (second photo) the underside looks as though it's missing. It makes this crinoid stem look like a few other types of fossils.

Other crinoid stems found on rock surfaces were more clearly Ectenocrinus simplex.

Site 2: Brachiopods

Rafinesquina sp. were abundant on site #2.

We found a layer in which the brachiopod Rafinesquina sp. was shingled and pushed around in the now-lithified mud. The layer indicates a large storm event in our geologic past.

Cincinnatina multisecta (formerly Dalmanella or Onniella multisecta)  are also abundant in certain layers on site#2. These layers, like the shingled Rafinesquina, act as marker beds for finding the relative position of the bed in the strata.

Site 2: Trilobites 

No whole trilobites were found that day on site#2. We did find fragments of Flexicalymene sp. trilobites. Here is a glabella (part of the head) of Flexicalymene sp.. 

Isotelus sp. fragments.were found on the surface of rocks, as shown in the next 3 photos.

That's it for this field trip. I hope you enjoyed it. If you want to know more about the sites along this scenic northern Kentucky byway, join the Dry Dredgers!

See previous trips down this scenic byway in northern Kentucky

October 2010
October 2008

Now let's see our May 2014 field trip to the Bellevue and Corryville Formations.


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