Pennsylvanian trilobite hash & crinoid?

[Mochaccino]

Hello,

 

I have two slabs that I would like ID help with, one is a hash plate with trilobite cephalons and pygidiums, the other has a crinoid calyx/crown.

 

I'm told they were collected in Reynolds County of Illinois, USA. I did some googling and I don't think there is a Reynolds county in Illinois, but there is a Reynolds village in Rock Island/Mercer County Illinois which is what I'm guessing the seller meant.
 

Anyways, assuming this info, the geological map of Illinois suggests that this locality consists of the Tradewater Formation which is Pennsylvanian in age:

https://isgs.illinois.edu/content/bedrock-geology-map-illinois

 

The crinoid calyx is small at just 1 cm across not including the very long primaxil spines. From what I've seen, primaxils produced as spines is a feature that seems uncommon in most geological periods but commonly seen in many Pennsylvanian crinoids. So I'm more convinced that the crinoid is Pennsylvanian.

 

On the other hand, the trilobite cephalons (also measuring about 1 cm) look very much like calymene/flexicalymene which are Silurian/Ordovician genera, so I'm a little more doubtful here. 
 

Anyways, here are photos. First the crinoid plate:

 

 

And the trilobite hash:

 

Thank you.

Edited January 23, 2023 by Mochaccino

[EMP]

I agree those trilobites are some kind of calymenid, which means this is Ordovician-Silurian and not Pennsylvanian. I haven't collected in Illinois, but from my experience in Wisconsin it looks like it could be from one of the upper Ordovician formations from the area (like the Maquoketa Group). 

 

As for the crinoids, I can't really say for certain, but I did find this ID guide for Pennsylvanian crinoids from nearby:

 

 

There are a few in there that look similar to me, but I've never been a crinoid guy. 

 

It's always possible that these were collected at separate sites that happened to be fairly close together geographically, and so they got lumped together by the original collector. That would explain the whole Ordovician trilobites, Pennsylvanian crinoids thing.

[Tidgy's Dad]

Can't help, but what a lovely crinoid! 

[connorp]

The trilobits look very much like Flexicalymene to me. Did the seller say these from the same site? Can you ask for clarifications on location from them?

[Mochaccino]

12 hours ago, EMP said:

I agree those trilobites are some kind of calymenid, which means this is Ordovician-Silurian and not Pennsylvanian. I haven't collected in Illinois, but from my experience in Wisconsin it looks like it could be from one of the upper Ordovician formations from the area (like the Maquoketa Group). 

 

As for the crinoids, I can't really say for certain, but I did find this ID guide for Pennsylvanian crinoids from nearby:

 

 

There are a few in there that look similar to me, but I've never been a crinoid guy. 

 

It's always possible that these were collected at separate sites that happened to be fairly close together geographically, and so they got lumped together by the original collector. That would explain the whole Ordovician trilobites, Pennsylvanian crinoids thing.

 

7 hours ago, connorp said:

The trilobits look very much like Flexicalymene to me. Did the seller say these from the same site? Can you ask for clarifications on location from them?

 

Thanks! I just double-checked with the seller and he says they are actually indeed from 2 different localities in northern Illinois, one Silurian-aged, and one Pennsylvanian near Mazon creek and by Reynolds. Perhaps that helps with getting identification?

 

EDIT: Kankakee County near Iroquois River. According to the Geological map this is indeed Silurian! So that's likely where the Trilo-plate came from.

Edited January 21, 2023 by Mochaccino

[Advantage]

Lovely specimens.

[connorp]

3 hours ago, Mochaccino said:

 

 

Thanks! I just double-checked with the seller and he says they are actually indeed from 2 different localities in northern Illinois, one Silurian-aged, and one Pennsylvanian near Mazon creek and by Reynolds. Perhaps that helps with getting identification?

 

EDIT: Kankakee County near Iroquois River. According to the Geological map this is indeed Silurian! So that's likely where the Trilo-plate came from.

This doesn't make sense. Reynolds is no where near the Mazon Creek deposits.

[Mochaccino]

9 minutes ago, connorp said:

This doesn't make sense. Reynolds is no where near the Mazon Creek deposits.

Ah Dang it, let me double-check.

[connorp]

30 minutes ago, Mochaccino said:

Ah Dang it, let me double-check.

Mazon Creek deposits are concentrated around the Morris/Braidwood area.

[JBkansas]

Kankakee is by Mazon Creek, maybe he just got the two mixed up.

 

Then again the Iroquois river is on the side opposite from Mazon Creek.

Edited January 21, 2023 by JBkansas

[Mochaccino]

1 hour ago, JBkansas said:

Kankakee is by Mazon Creek, maybe he just got the two mixed up.

 

I think that's most likely the case. He says he collected these MANY years ago and is relying on old records.