Unknown from Jacksboro Texas

[BobWill]

I found this at the Lost Creek dam spillway in the Finis Shale of the Upper Pennsylvanian at Jacksboro Texas. The patterns remind me of cartilage.

 

            

 

 

                                       other side

 

 

                                                edge

 

more photos in reply

 

[BobWill]

Here is a close-up on one end

 

 

                                                           closer look at dark spot below

 

 

                                                     closer

 

 

 

                  

 

                                               Close-up of other side

 

 

odd bit stuck to first side

 

 

another odd bit

 

 

another close-up of back side

 

[FossilDAWG]

The "odd bits" seem to be crinoid stem or arm ossicles to me.  Not sure about the main bit.  I would gave guessed eroded bryozoan but I'm not familiar enough with shark cartilage to be sure of the difference.

 

Don

[Tidgy's Dad]

Looks more like a tabulate coral of some sort to me. Something like Favosites. 

But really, really small! 

[BobWill]

6 hours ago, FossilDAWG said:

The "odd bits" seem to be crinoid stem or arm ossicles to me.  Not sure about the main bit.  I would gave guessed eroded bryozoan but I'm not familiar enough with shark cartilage to be sure of the difference.

 

Don

5 hours ago, Tidgy's Dad said:

Looks more like a tabulate coral of some sort to me. Something like Favosites. 

But really, really small! 

 

Don, I agree with tiny crinoid parts and bryozoan was my first guess before I looked closer at the parts that look a little like the cartilage on this known fossil.

 

 

 

Tigy's Dad, I see what you mean but views number 4 and 6 would be hard to fit with coral.

 

[KimTexan]

If it is anything like stuff I have found there many things got covered with bryozoan colonies. So it could possibly be something with bryozoan layered on top.

[Herb]

looks like coral and crinoid stems pieces to me

[BobWill]

I meant to refer Tidgy's Dad to the third picture for the thickness which doesn't exceed 2.5mm. If the back side were an encrusting bryozoan it would be covering something very thin. It's hard to tell from the photo but those are raised knobby features rather than a lattice in pictures 8 and 11.

[Al Dente]

Way too small to be coral. I don’t think I’ve seen prismatic cartilage this small either. My guess would be bryozoan.