28th Annual Digging the Past Event

 

Yesterday I volunteered at the Falls of the Ohio State Park (Clarksville, Indiana USA) where I spent about 5 hours setting up, identifying and digging up Silurian fossils for visitors to the park. Most of my time was at the Waldron Shale piles containing Silurian period fossils. The main building was closed due to the air conditioning system being replaced. It has been hot this last week and as a result there was a very light turn out, maybe the fewest number of people I have seen since I started volunteering at this annual event.

The heavy rain the night before revealed a number of fossils on the surface but it was extremely muddy and I almost lost my shoe several times getting stuck in the mud. After splitting some of the shale rocks, I found several Eucalyptocrinites crinoid cups and a holdfast, and brachiopods which I gave away to visitors. One visitor found two trilobite pygidium imprints of a Dalamites and Arctinerus.

 

These next images show Fardenia brachiopod fossil imprints.

All in all a somewhat nice day. It was in the 80s F in the morning and was getting hotter by noon. Working in the shale piles was muddy. I did not get to check out how the mineral piles or Devonian period fossil piles were going. The Devonian one was very mucky and wet.

Crinoid Holdfast on a Crinoid Calyx

This post is of an Eucalyptocrinites (Goldfuss, 1831) holdfast fossil that grew on a fallen Eucalyptocrinites crassus (Hall, 1863) calyx cup. Fossil found in the Waldron Shale of Clark County Indiana USA. It dates to the Silurian Period.

Fossil on display at Falls of the Ohio Interpretative Center Clarksville Indiana USA as of December 2022.

Myelodactylus? Crinoid Fossil

 

I found this rock in a pile of river rock in Louisville, Kentucky USA. It appears to be a crinoid holdfast. Rock contains a lot of crinoid fossil fragments.

It reminds me of a Myelodactylus crinoid fossil. See these previous posts of ones found in this area:

https://louisvillefossils.blogspot.com/2014/05/myelodactylus-crinoid-attached-to.html

https://louisvillefossils.blogspot.com/2010/06/silurian-crinoid-arm.html 

 https://louisvillefossils.blogspot.com/2020/02/myelodactylus-convolutus-crinoid-from.html 

https://louisvillefossils.blogspot.com/2020/02/myelodactylus-convulotus-crinoid-from.html

https://louisvillefossils.blogspot.com/2010/05/silurian-crinoid-arm.html 

Bryozoan Holdfast Fossil

In September 2021, I was collecting in Alpena Michigan USA. While there I found something that was not immediately apparent what it was. After consulting with Paleo Joe he told me it was a fan bryozoan holdfast fossil. It was found in the Potters Farm Formation of the Traverse Group. The fossil dates to the middle Devonian Period (Givetian Stage). Only found this one and was a little thrown off as I don't remember ever encountering a holdfast that looked like this.

Waldron Shale Cystoid Holdfasts?

 

On September 21, 2020, I posted this fossil but was unsure what exactly it was. After consulting with my cousin Kenny and Ken (a Waldron Shale fossil hunter of over 40 years), I am leaning toward and identification that this fossil is a cluster of cystoid holdfasts.

Kenny showed me a paper entitled Taphonomy of diploporite (Echinodermata) holdfasts from a Silurian hardground, southeastern Indiana, United States:palaeoecologic and stratigraphic significance by James R. Thomka and Carlton E. Brett published in 2014 at Geol. Mag. 151 (4) in 2014 pages 649-665. It shows a variety of fossils similar to the one pictured that are thought to be parts of Silurian cystoid fossils.

A link to that paper is here:

http://webcentral.uc.edu/eprof/media/attachment/eprofmediafile_2376.pdf

The fossil was found the Silurian Period (Wenlock: Homerian Stage) in Clark County Indiana, USA. If this fossil is a series of holdfasts, then they grew in close proximity to one another.

I have found numerous cystoids in the Waldron Shale notably Caryocrinites (Say, 1825) and Holocystites (Hall 1864) aka Megacystites (Hall, 1865). See previous entries:

https://louisvillefossils.blogspot.com/2010/06/holocystites-cystoid.html

https://louisvillefossils.blogspot.com/2011/08/caryocrinites-cystoid-in-matrix.html

https://louisvillefossils.blogspot.com/2011/10/caryocrinites-persculptis-cystoid.html

https://louisvillefossils.blogspot.com/2012/05/pyrite-encrusted-caryocrinites-cystoid.html

https://louisvillefossils.blogspot.com/2012/12/silurian-caryocrinites-cystoid-fossil.html

Digging The Past Event

Saturday, August 29, 2020 The Falls of the Ohio State Park held their Digging the Past event. It has been several years since I had last attended back in 2015. In the past I always enjoyed identifying what people found in the collecting piles and elaborating about the minerals or fossils. The downside is the place to do this was at the cleaning screens and by the end of my shift I was quite wet and sometimes muddy.


This year everyone was in masks and social distanced so I only identified a couple of things. I volunteered to give a talk about fossil collecting but ending up talking to 2 people. While I was there I would estimate at least 100 people visited. Most of my time was spent speaking with exhibitors, helping with fundraising by selling fossil/mineral egg cartons or working around the presentation area.

At the end I went in the collecting area which was really muddy and my Estwing rock hammer split apart large pieces of Waldron Shale. It was almost impossible to find fossils in the muddy shale. Splitting the rocks helped in that I found several Eucalyptocrinus crinoid holdfasts, Metopolichas breviceps trilobite cephalon and Dalmanites pygidium.

Outside of the rocks, I found a small Stegerhynchus brachiopod and Platyostoma gastropod. The crowds would have probably been larger if no Covid epidemic and the weather being overcast with it looking like it was going to rain most of the morning. It was nice to be back and I got some exercise walking along the river front and breaking rocks.

Here are some links to past events I have participated at the Falls of the Ohio State Park:

https://louisvillefossils.blogspot.com/2015/09/digging-past-event-2015.html

https://louisvillefossils.blogspot.com/2014/09/digging-past-event-at-falls-of-ohio.html

https://louisvillefossils.blogspot.com/2013/08/earth-discovery-day-august-2013.html

https://louisvillefossils.blogspot.com/2012/10/earth-discovery-day-2012.html

https://louisvillefossils.blogspot.com/2011/09/fossil-festival-fun.html

https://louisvillefossils.blogspot.com/2011/09/2011-falls-fossil-festival.html

https://louisvillefossils.blogspot.com/2010/09/fossil-festival-2010.html

Archimedes Bryozoan Fossil with Holdfast

Here is a rare example of an Archimedes sp. bryozoan fossil with part of holdfast (root like structures) exposed. It was used to anchor it to the seabed. Another rare feature is the part of the netting or mesh structure that extended out into the water along the edge of the creature's screw shape. The name for water pump screw credited to the Greek engineer Achimedes of Syracuse (287-212 BC).

The naming of this genus is credited to Indiana's first state geologist David Dale Owen (1807-1860) to his publication, A Geological Reconnoisance and Survey of the State of Indiana in 1837 and 1838 in 1838. He later wrote an article for The American Journal of Science and Arts, Volumes 43-44 (1842) entitled Regarding Human Foot-Prints in Solid Limestone. He writes "characterized by a very remarkable fossil coralline, resembling the Retepora of Lin., but verticillated spirally like a continuous screw; described by Lesueur under the appropriate name of Archimedes.*" He writes that on page 19 with a foot note listing, "I am not sure that Lesueur ever published his description of this fossil; but I know that while he resided here (at New Harmony) he engraved a plate containing several views of it, with that intention. He considered it, I believe, a new genus; but it may be only a new species of Retepora; if so, most aptly entitled Retepora Archimedes."

Owen is referring to the French naturalist Charles Alexandre Lesueur (1778-1846). He lived at New Harmony Indiana from 1826-1837. He was good friends with Thomas Say who named the Pentremites blastoid fossil genus and is buried at New Harmony.

The fossil pictured above was part of the James Conkin collection. This bryozoan existed in the Mississippian Period, the genus died out in the Permian Period. No locality was listed with this fossil but I am guessing it was found in Indiana or Kentucky. Thanks to Kenny for the picture.

Crinoid Holdfast on Dead Crinoid Stem

This pictures show a crinoid holdfast growing on the side of a fallen crinoid stem. The fossils were found in the New Providence Formation of Scott County, Indiana USA. The fossils date to the Mississippian Period. Thanks to Kenny for the images.

Ancyrocrinus Crinoid Fossil Anchor

This crinoid had any interesting angle on existing in the Devonian Period sea. At its base was a pod with spikes that allowed it to anchor on the seabed. These pictures show an Ancyrocrinus sp. crinoid fossil. It was found in the Beechwood Limestone of Clark County, Indiana USA.

Unidentified Crinoid Holdfast Fossil

This image is of an unidentified crinoid holdfast attached to larger crinoid stem fossil. It was found in the New Providence Formation (Keokuk) of Scott County Indiana USA. This creature existed in the Mississippian Period. Thanks to Kenny for this image.

Microfossil Crinoid Pieces from Clark County Indiana

My cousin recently sent me some images of crinoid fossils he has been finding in the New Providence Formation of Clark County, Indiana, USA. The fossils date to the Mississippian Period (Carboniferous). All pictures were taken using a microscope and have an approximate field of view of 2 mm.

Thanks to Kenny for the images.

Unidentified Crinoid Holdfast

It is difficult to sometimes identify Devonian Period crinoid stems without their calyx. This specimen was found in Clark County, Indiana, USA. The fossil fragment has a lot of texture.

Unprepped Silurian Crinoid Holdfast

This crinoid holdfast is maybe the most extensive one I have every found. It is still quite embedded in Waldron Shale matrix but the large number of roots are exposed. Somewhat amazing how much this animal has such similar characteristics to that of a plant. While not able to make an exact identification it appears to be the holdfast of an Eucalyptocrinus of the Silurian Period. Fossil found in Clark County, Indiana, USA.

On the other side of the matrix piece, this smaller holdfast was found that appears to be like a large tap root with small branches coming off it.

Identification is based off of images of Eucalyptocrinus roots (holdfasts) from illustrations from Plate 19 (Figures 6-7) Indiana Department of Geology and Natural History Eleventh Annual Report John Collett State Geologist 1881.

Also plate 20 shown below.

Life on a Brachiopod

This specimen is an interesting example of biodiversity layer upon layer. The top layer consists for at least 5 crinoid holdfast probably belonging to the Eucalyptocrinus. See following magnified images for more detail. These holdfasts attached to an encrusting bryozoan that could be either Lichenalia or Sagenella. The bryozoan is covering an Eospirifer brachiopod.

Creatures lived in the Middle Silurian Period (425-419 million years ago). Fossil found in the Waldron Shale of Clark County, Indiana, USA.