Mecca Quarry Shale finds

[connorp]

I had a great time hunting with ESCONI at the Starved Rock Clay Pit. It exposes the Pennsylvanian aged Francis Creek Shale and Mecca Quarry Shale. There were tons of concretions lying around, but we were told they are usually empty and rarely split well, so I didn't bother. I was really there for the black shale anyways. I found a bunch of bits which may prove to be more interesting after prep, but here are the more exposed finds of the day. I am not familiar with this fauna, so I was hoping to get help with IDs.

 

#1) I found a few similar specimens. Best guess is coprolite.

 

 

#2) Not sure if this is a fossil. Maybe coprolite or an arthropod carpace. Or just a mineral stain.

 

 

[connorp]

#3) Not sure what this crystal is, but there was tons of it here. This piece looked suggestively like a cephalopod cross section. Probably not, but posting to be sure.

 

 

 

#4) This is interesting. Absolutely no idea. Part of an arthropod exoskeleton?

 

[connorp]

#5) This brachiopod was pretty common. I found a bunch of other bits but this is my most complete one. Not the best preservation though, I saw a few others people found which were better. Anyone recognize it? Righthand picture shows the counterpart as well.

 

[connorp]

#6) When I first saw this, I thought I found a Listricanthus spine which was my goal for the day, but it doesn't appear to be one (or two). Maybe some other kind of fish spine?

 

 

 

#7) No idea on this large thing.

 

[connorp]

Oops, mods can you move this to

Fossil ID. Thanks.

[connorp]

2 hours ago, connorp said:

#5) This brachiopod was pretty common. I found a bunch of other bits but this is my most complete one. Not the best preservation though, I saw a few others people found which were better. Anyone recognize it? Righthand picture shows the counterpart as well.

 

I now believe these are actually the bivalve Dunbarella sp.

[connorp]

A couple closeups. I believe these are bony fish spines, texture looks like bone. Maybe acanthodian?

 

[connorp]

And here’s a close up of #4. Maybe cartilage?

 

[RCFossils]

I love the Mecca Shale!

Did anyone find any complete fish?

I would agree that the first example is likely fish bits (likely paleoniscoid).

These masses are often referred to as regurgitates.

I cannot make out much on #2 but think it is likely mineral staining.

The third fossil appears to be a cephalopod.

The fourth is possibly a partial concavicaris but difficult to say for sure.

The fifth is the pecten Dunbarella.

The sixth does appear to be acanthodian spines. I will post a picture of a more complete specimen for comparison.

I think #7 is likely plant material.

 

[RCFossils]

Here is a partial example of a Mecca Shale acanthodian for comparison.

[westcoast]

9 hours ago, connorp said:

I now believe these are actually the bivalve Dunbarella sp.

I agree that Dunbarella  is a good call on these 

[connorp]

4 hours ago, RCFossils said:

I love the Mecca Shale!

Did anyone find any complete fish?

I would agree that the first example is likely fish bits (likely paleoniscoid).

These masses are often referred to as regurgitates.

I cannot make out much on #2 but think it is likely mineral staining.

The third fossil appears to be a cephalopod.

The fourth is possibly a partial concavicaris but difficult to say for sure.

The fifth is the pecten Dunbarella.

The sixth does appear to be acanthodian spines. I will post a picture of a more complete specimen for comparison.

I think #7 is likely plant material.

 

I read a good deal of "The Paleoecological history of two Pennsylvanian black shales" by Rainer Zangerl this morning. I now agree with #1 being regurgitate. In Zangerl's text, he mentions a lot of of driftwood/stems being found in the Mecca Quarry Shale, so plant material seems a good candidate for #7. I feel like #2 might be a coprolite? I'm going to get it under a microscope when I get back to uni to see if I can make out any small bone fragments in there. As for #4, I did consider Concavicaris, but the pattern doesn't seem to watch up with the complete specimen you posted back in 2012. I wish I found more of it to be sure though.

 

What I find interesting about the spines is the associated fragments, especially around the larger on top. Zangerl mentions that a lot of fish material from these shales are regurgitated, so maybe these were partially digested?

 

I don't know if anyone found a complete fish, although I did see two guys hauling off a large block of shale so it's possible. Most of the other finds I saw were Listricanthus, Dunbarella, and cephalopods. It was a pretty fun but challenging hunt. Almost all the fossils I found came from only 3 blocks of shale, and I probably split open over 50.

 

Thanks for all your help.

[connorp]

Here are a couple shots of the quarry. Good time except for when I got stuck in a deceptively deep clay pocket and trashed my clothes.

 

 

[deutscheben]

Dang, you ended up with some good finds, @connorp! That set of acanthodian spines is outstanding, and the regurgitate and bivalve are nice too. (I realized I had been referring to the shells as brachiopods yesterday, but they do all seem to be bivalves instead). I thought about trying to haul a 2x3 foot piece of shale with intriguing things on it back to my car, but then I cut my finger and also thought about my full workspace and decided against it...  

[connorp]

21 minutes ago, deutscheben said:

Dang, you ended up with some good finds, @connorp! That set of acanthodian spines is outstanding, and the regurgitate and bivalve are nice too. (I realized I had been referring to the shells as brachiopods yesterday, but they do all seem to be bivalves instead). I thought about trying to haul a 2x3 foot piece of shale with intriguing things on it back to my car, but then I cut my finger and also thought about my full workspace and decided against it...  

I definitely brought too much back. Probably around 100 lbs of shale. I've spent the day breaking down larger blocks and found a few more Dunbarella already, although all partials.

[connorp]

Alright here’s one more bivalve that I found while breaking down larger blocks for storage. I looked through a list of bivalves from the MQS but honestly they all look the same to me. Not sure if this specimen is complete enough to identify but we’ll see. It was photographed wet.

 

[connorp]

On 8/21/2019 at 3:26 AM, connorp said:

Alright here’s one more bivalve that I found while breaking down larger blocks for storage. I looked through a list of bivalves from the MQS but honestly they all look the same to me. Not sure if this specimen is complete enough to identify but we’ll see. It was photographed wet.

 

Any thoughts? Went through the guide I have again but still couldn’t figure out exactly what species this guy is.