Enrolled Phacops rana

First two images of an enrolled Phacops rana (Green, 1832) trilobite fossil found in the Silver Creek Member of the North Vernon Limestone of Clark County, Indiana.  This fossil has been sandblasted though concrete like residue still remains in between thorax segments.  Creature existed in the Middle Devonian Period.  Nice size for this trilobite at about 3 cm wide.

Still not been able to determine if pygidium or cephalon exists on this fossil due to hardness of matrix.  Tried using the engraver some to expose more of fossil but conservative use due to fragile nature of fossil.

Fossil in plate before sand blasting.

Phacops Trilobite Molts

This post shows some of the Phacops rana (Green, 1832) trilobite molts I have found over the last year. These fossilized remains were found in Clark County, Indiana or Jefferson County, Kentucky. While not museum grade finds and none are intact enrolled trilobites, they are still nice finds. The trilobite fossils most likely are from the Jeffersonville Limestone layer of the Devonian Period.  If you are a fossil collector in the United States of America, this trilobite is always nice to find.  Some of the best looking Phacops (Emmrich, 1839) trilobites are found in the Silica Shale in Ohio as opposed to these limestone fossils.

This trilobite is most interesting because of the lens of its compound eye.

Enrolled Phacops trilobite thorax pieces

 

Close up of two enrolled Phacops thorax pieces

 

Two fossils that need to have some matrix removed from the thorax segments

A selection of Phacops trilobite cephalon pieces

Close up of one of the cephalons

 

Phacops Trilobite From Ohio

This trilobite is from Lucas County, Ohio. This trilobite is probably my favorite because it is the one I find the most in the Louisville, Kentucky area. The creature lived in the Paleozoic Era in the Middle Devonian Period (around 395 million years ago).

This one was probably found in Silica Shale. It is from the phylum Arthropoda and was called Phacops rana (I have also seen specimens from Ohio referred to as Phacops rana crassituberculata). This trilobite might also be known by the name Eldredgeops rana. The fossil trilobite must be found quite a bit in Pennsylvania was well since it is their state fossil.

This specimen is enrolled sort of like the modern day isopod Armadillidium ("pill bug") does. Also note the large compound lens eyes. This type of eye is called Schizochroal allowing the trilobite to have 360 degree vision. Since the creature had this ability I am guessing it was preyed upon by something (maybe a shark).

Thanks to an anonymous friend for the images.

Devonian Period Phacops Trilobite

The following are some trilobite fossil pictures taken using a glass plate to eliminate shadow. The lighting could be better and my background cloth is a little wrinkled. I did not set up the light box but instead used a much more primitive setup.

The fossils were found in Clark County, Indiana. They are from the Devonian Period.

This first three images are of the same fossil. It is one of the better specimens I found that day. The Phacops rana trilobite is a little over 2 cm wide. It is possible the whole trilobite is intact. The pygidium and lower thorax are partially covered by matrix. I will try air abrasion cleaning at a later date. Unfortunately, the compound lens of the trilobites eye are gone from one side. I count 8 thorax segments visible.




Welcome to the land of fossils in Clark County, Indiana. This rock layer might be Jeffersonville Limestone. Beautiful day to collect!


Phacops rana cephalon that is probably a molt. Two views of the same fossil.


Fragment of a Phacops rana cephalon that seems to have a bit of black maganese on it.


Upside down cephalon embedded in matrix. This trilobite is probably a Phacops rana.

Devonian Fossils Found Today

I am tired after collecting at a KYANA field trip this morning. A large group showed up of both KYANA members and a junior group from Evansville. The weather was great and everyone seemed to have a good time. I took a panoramic picture around noon.

This is a trilobite (maybe a Crassiproteus) found in what I guess the North Vernon Formation in Clark County, Indiana. It was not found by me but someone else on the trip. It was enrolled and I don't think it was a molt.

This blastoid was found by the same person who found the trilobite. It is probably an Elaeacrinus verneuili (Römer [aka Roemer], 1851) found in the Jeffersonville Limestone in Clark County, Indiana.

Phacops rana on a Brachiopod

A cousin found this in Clark County, Indiana. It is a small Phacops rana missing is part of its rear thorax and pygidium. The Devonian brachiopod is unidentified. I like how it is just sitting on the shell.

Phacops rana Trilobite aka Eldredgeops

Here is one of the largest Phacops rana trilobite molts I have found. It is about 4 cm wide. It is quite broken up and has piece of bryozoan stem sticking through it.

It was found in Clark County, Indiana (across the Ohio River from Louisville, Kentucky) in the North Vernon Formation. This creature existed in the Devonian Period.

Devonian Trilobite

Here is a trilobite tail piece embedded into a rock found in Jeffersonville, Indiana off Middle Road in 2004. It is probably a Phacops rana. Since they seem pretty common in that area.

Phacops rana

Here is a trilobite head of the Phacops rana found in the Jeffersonville Limestone layer which can be found in Speed, Sellersburg, and Jeffersonville Indiana that I know of.

This is just a molt where the creature grew bigger and discarded its old shell which got buried and fossilized over time.