Wednesday, April 23, 2014

A pair of Pleurotomaria sp. Gastropods from France

Here are a pair of Pleurotomaria sp. gastropods that come from a quarry near Evrecy (southwest of Caen), France that excavates rock from the Bajocian stage of the Jurassic. The rock is very distinctive with a tan color that is speckled with small red hematite nodules.

The first fossil is Pleurotomaria textilis still attached to the matrix.

Then we have Pleurotomaria granulosa. The shell is not as tall as P. textilis but it still has that distinctive decoration along the whorls.

Thanks to my friend Gery who sent me these fossils.

Monday, April 21, 2014

Blastoids from Michigan

A few years ago a member of the Fossil Forum gave me these two blastoids in matrix. What I know about them is that they came from the Alpena area of Michigan and are Devonian in age. I reached out to my friend Joe K. for some ID help and he suggested that it comes from the Thunder Bay formation and would be classified as a Heteroschisma subtrunctatum.

Specimen #1

Specimen #2

I need to get both specimens cleaned and prepped so that they are more visible. The Thunder Bay formation (or limestone, depending on who you are talking to) is the uppermost layer of the Traverse group in Michigan which places it as latest Givetian stage of the Devonian.

Saturday, April 19, 2014

Megistocrinus sp. crinoid calyx from Marilla, NY

It's not a great fossil but the specimen below is one of the few Crinoid calyxes that I have found. It's a weathered Megistocrinus sp. calyx that I found in the Deep Run mbr. of the Moscow formation.I found it in a creekside exposure of Buffalo Creek near Marilla, NY.

Here is the matrix with the bottom of the calyx sticking out on the right hand side.

A closer view of the side where you can see some of the geometry of the plates that make up the calyx. along the top of the calyx are some round knobs where the arms once were attached.

Another side view
A view of the bottom with the basal plates where the stem would have attached.
The patterns on the calyx plates are not those that would have been seen in life. Since the specimen has eroded due to exposure to the elements the marks on the plates are more likely a crystallization pattern that is preferentially weathered.

The Deep Run mbr. of the Moscow Fm. is stratigraphically older than the Windom shale and is not found along Lake Erie. The town of Marilla is located about 15 miles east of Buffalo and the exposure there of the Deep Run Mbr. is only about a foot thick. I need to find another exposure farther east so that I can explore this rock unit more.

Thursday, April 17, 2014

Some new finds from the Kashong Shale

This past spring I hunted among the eroded remnants of the Kashong Shale near Greigsville, NY and found a few interesting fossils.

This is a very narrow Crinoid holdfast that must have grown on a jumble of thin shell material.

It is not uncommon to find pieces of shell hash that have flat bryozoans incoporated in with them. This is a piece of matrix that has a Taeniopora exigua piece on one side...
... and some Sulcoretipora incisurata on the other side.

Lastly I found a portion of a crushed Blastoid that may have been a Nucleocrinus or Devonoblastus.

All the above specimens were found in the Kashong shale member of the Moscow formation which is middle Devonian in age (Givetian stage).

Tuesday, April 15, 2014

Melocrinites sp. crinoid from Germany

This will be the last of the fossils that I received from my friend Nils to be featured for a while. I have a few more Devonian fossils from Germany to feature but I will post them up later. The featured fossil for today is a Melocrinites sp. calyx from the Oos formation (Devonian, Fransian) near Wallersheim, Germany. It's a little rough but you can make out the calyx plates and arm attachment points.

Dorsal surface
 Oral surface

These next photos are of the calyx in profile and turned about 60 degrees counter clockwise between photos.

Thank you to Nils for this specimen!