Pennsylvanian zipper fossil from Texas

[BobWill]

This photo was sent from a person who knows nothing about fossils or geology so the questions far outnumber any answers. We hope to see it in person in 2 weeks or so and will then determine the location, confirm the formation, and provide the size.

 

The area around Jacksboro Texas, the only information we have now, is mostly the Graham formation, so that makes it marine deposits in the Cisco group, Late Pennsylvanian. I have tried to imagine it could be a bryozoan or some kind of plant but nothing I know of is a good fit. I thought maybe someone here might recognize it.

 

[Sjfriend]

I think you were right..... that's a zipper. Ok, really I have no idea

[Rockwood]

Are you quite certain it isn't a badly crushed ammonite ?

[DPS Ammonite]

Slight resemblance to Clathrocrinus crinoid arms, a Pennsylvanian genus.

 

 

 

 

 

 

 

 

 

Edited October 23, 2021 by DPS Ammonite

[ClearLake]

My first impression was an Archimedes (I guess it would be several) but I realize that doesn’t totally fit with what you think you know about it. It is a bit if a mystery, just want to expose more of it!!

[BobWill]

15 minutes ago, DPS Ammonite said:

Slight resemblance to Clathrocrinus crinoid arms, a Pennsylvanian genus.

 

That looks very close. I'm surprised Peter Holterhoff didn't suggest that but he may have had a reason to rule it out. I also asked Mark McKinzie. That thing looks more like a zipper than mine!

 

I suppose it is more of a zig-zag while mine has sort of alternating nodes breaking off the sides. The thing on the right is similar to the zipper strings but looks a little like a dermal denticle.

[DPS Ammonite]

Also similar to an external mold of crinoid arms especially one at upper right.

 

 

Even better a Delocrinus.

Edited October 23, 2021 by DPS Ammonite

[DPS Ammonite]

Here is a Deltocrinus from Jacksboro: smoking gun? An exterior mold of these arms?

 

http://www.thefossilforum.com/index.php?/topic/113841-texas-pennsylvanian-weekend-trilo-crinoids-goniatites-and-more/

 

 

[Tidgy's Dad]

I think these are parallel bryozoan pinnules; branches of a the genus Penniretepora would appear most likely, but maybe Pinnatopora or Acanthocladia. 

A close up of the branches and zooecia would be necessary for someone to tell which.  

 

[Missourian]

Possibly a trace fossil of some sort?

 

The leaves and twigs in the lower left corner indicate that they could be quite large.

[DPS Ammonite]

20 minutes ago, Missourian said:

Possibly a trace fossil of some sort?

 

The leaves and twigs in the lower left corner indicate that they could be quite large.

The leaves and twigs are modern. The Jacksboro area has mostly Pennsylvanian fossils.

[Missourian]

1 hour ago, DPS Ammonite said:

The leaves and twigs are modern. The Jacksboro area has mostly Pennsylvanian fossils.

 

I was referring to scale.

[DPS Ammonite]

1 hour ago, Missourian said:

 

I was referring to scale.

Of course, I misread your reply.

[Top Trilo]

I don't think trace fossil is likely, as there are at least three of these "lines" next to each other and a fourth partial one.