Ordovician Period Trilobites

Two trilobite fossils are shown in this entry. The first is an intact enrolled Flexicalymene sp. trilobite. It is probably Ordovician Period and found in Kentucky. Thanks to Mary Ann for letting me photograph it. I forgot to ask about how it became part of her collection.  With some air abrasion cleaning, this specimen could be look'in nice!

The second trilobite fossil is just a fragment.  It is an Isotelus sp. I recently found on a field trip to Franklin County, Kentucky.  The original find was just the back of the cephalon plate with a broken genial spine. Using a Dremel engraving tool, more of the cephalon was exposed and the eye appeared as well.  Unfortunately, my inexperience with the engraver caused some white scratch marks on the cephalon and the eye piece.



This fossil was found in Lexington Limestone and is from the Ordovician Period.  The particular trilobite is the official state fossil of Ohio.  It was awarded that distinction by the legislature in 1985.

The image shows a close up to where the genial spine once protruded off the cephalon.

Possibly, these creatures reached lengths to almost a meter.

Flexicalymene Trilobite - Kentucky

Here are some pictures of a specimen I have posted before but this view is of the pygidiums. Also these pictures were taken in full sun light while the previous batch were under fluorescent light. These pictures are of a cluster of the remains of three Flexicalymene trilobites preserved in the Kope Formation of Carroll County, Kentucky.

They still need more work with the engraver and air abrasive cleaner.

Ordovician Flexicalymene Pygidiums

Yesterday, KYANA Geological Society stopped by Carroll County, Kentucky for some Ordovician siteseeing after a marvelous tour of the Cincinnati Museum Grier Collections Center fossil department. I took a lot of pictures of specimens to post! Here is a sample of Flexicalymene trilobite pygidium pieces I found on the roadcut. I think we were in the Kope Formation of the Ordovician Period.

This first piece is of an enrolled Flexicalymene with a damaged cephalon and pygidium.

Ordovician Flexicalymene Trilobite

I picked this rock up in one of the eastern Louisville, Kentucky road cuts that has Ordovician Period fossils. Originally, I was attracted to a conical shaped cephalopod mold looking rock. Once I picked it up, it had a small exposed area of a trilobite thorax. The ridges of the thorax had matrix in them so it seemed like a good idea to sand blast them clean.

I took it to my cousin and pointed out that a cephalon was partially visible and maybe a whole trilobite was there. So he sandblasted the rock for about 20 minutes and what a surprise. There were sections of three Flexicalymene trilobites there. The largest one is about 2 cm long.

This is a work in progress. More matrix needs to be removed to see if another cephalon exists. Notice the white marks on the rock made by the engraver tool.

Flexicalymene Trilobite

Here is an Ordovician Period trilobite called Flexicalymene from the Mt. Washington area in Kentucky. It is approximately 2 cm in length and has been cleaned with a sand blaster. It is about the only one I have found that is stretched out and almost fully intact.

I found it on a field trip with KYANA Geological Society (www.kyanageo.org) of Louisville, Kentucky.

Flexicalymene Trilobite Tail

Here is a possible Flexicalymene trilobite tail found in Trimble County, Kentucky. I think the rock I was looking in had Ordovician fossils in it.

There appears to be a piece of bryozoan in the rock as well.

Ordovician Trilobite Pygidiums

Here are some Ordovician trilobite pygidiums (or tails) found at the Bardstown Road cut outside of Louisville, Kentucky. They were found in June 2008 during about a 90 minute search.

They are small less than a centimeter across.

I would guess they belonged to Flexicalymene meeki which seemed to be popular in this rock layer.

Flexicalymene meeki

This trilobite was found near Mt. Washington, Kentucky (a little ways east of Louisville) on the Bardstown Road cut.

I spent time trying to figure out whether this was Calymene or Flexicalymene because the eyes are partially obstructed by matrix. The nose seems small and the head (cephalon) triangular. It was found in Ordovician rock so with the previous two features rules out a Phacops trilobite. I counted 13 segments in the thorax which puts in the correct range of 11-13. The tail or pygidium is slightly broke off and at an angle from the rest of the body.

Eventually, this specimen will be sand blasted to see if more detail of the head can be revealed.

Good trilobite research >webpage

Flexicalymene or Calymene Trilobite

This blog is to highlight fossils found around Louisville, Kentucky and southern Indiana. So to start it off I found a fossil while cycling this morning on the side of the road. Usually, the trilobite is one of the hardest to find. For those who do not know, a trilobite is a completely extinct creature that is an arthropod. Arthropods are spiders and crabs today. The trilobite might be closest related to the horseshoe crab of today.

I was surprised to see this fragment in the gravel spot in the grass. Since it was in a mix of gravel it is hard to say if it weathered out the ground or was dropped there. The rock seems almost like sandstone and the fossil is an imprint. I am wondering if it is Silurian period but it could be Devonian.

Usually, I find Phacops trilobites in this area and a lot of times I just find part of the tail section. So this is nice to find an almost intact head and enough of it to see it matches narrow nose with small eyes and a bump in front of each eye.

After researching another trilobite, this appears to be Silurian in age. The question is now is it a Calymene celebra shown at the Kentucky Paleontological Society webpage link or a "Flexicalymene" celebra shown on page 108-109 figure 1 in the Fossils of Ohio book (1996, Ohio Department of Natural Resources, Bulletin 70).