Unknown "stick" from Jacksboro Texas

[BobWill]

I found this 16mm long, slightly tapered stick-like specimen at the Lost Creek Lake spillway near Jacksboro Texas in the Finis Shale member of the Graham formation, Late Pennsylvanian. Until I got a closer look I thought it was an encrusting Bryozoan but this texture appears to be much less organized than the pores on them. It is similar in texture, but more coarse, to the material found in the cores of some possible concretions which have been described as burrows with a core (?) that occur frequently there. The end view shows a thin, shell-like outer layer which is also on some of the cores of the concretions.

 

A burrow with a core never made any sense to me anyway but I don't usually get a look at the core protruding out like these for a look at their surface texture so the similarity caught my eye. Besides the finer texture the ones in concretions do not seem to taper like this stick. I wonder if they could be some kind of plant material. We find some here but it is marine so it would be wood that floated out and sank.

 

 

 

 

 

Here are two of the "burrows" or maybe concretions. The second one has odd, randomly spaced rings around it.

Edited September 4, 2021 by BobWill

[DPS Ammonite]

39 minutes ago, BobWill said:

I found this slightly tapered stick-like specimen at the Lost Creek Lake spillway near Jacksboro Texas in the Finis Shale member of the Graham formation, Late Pennsylvanian. Until I got a closer look I thought it was an encrusting Bryozoan but this texture appears to be much less organized than the pores on them. It is similar in texture, but more coarse, to the material found in the cores of some possible concretions which have been described as burrows with a core (?) that occur frequently there. The end view shows a thin, shell-like outer layer which is also on some of the cores of the concretions.

 

A burrow with a core never made any sense to me anyway but I don't usually get a look at the core protruding out like these for a look at their surface texture so the similarity caught my eye. Besides the finer texture the ones in concretions do not seem to taper like this stick. I wonder if they could be some kind of plant material. We find some here but it is marine so it would be wood that floated out and sank.

 

It looks slightly like a worn Tabulipora bryozoan covering a sponge. Maybe the whole thing is a new sponge.

 

 

EDIT:

 

Could it be the inner filling of a Opiomorpha burrow with impressions of the rounded fecal pellets Compare the round structures by size and shape with the known Opiomorpha burrows at the site.

 

https://ichnology.ku.edu/invertebrate_traces/tfimages/ophiomorpha.html

Edited September 4, 2021 by DPS Ammonite

[BobWill]

7 hours ago, DPS Ammonite said:

It looks slightly like a worn Tabulipora bryozoan covering a sponge. Maybe the whole thing is a new sponge.

 

 

EDIT:

 

Could it be the inner filling of a Opiomorpha burrow with impressions of the rounded fecal pellets Compare the round structures by size and shape with the known Opiomorpha burrows at the site.

 

https://ichnology.ku.edu/invertebrate_traces/tfimages/ophiomorpha.html

 

 

Thanks John. I considered both of those and one or the other may be right. The only problem I had was trying to reconcile the thin outer layer which these both seem to have. I sent most of my burrows off to an ichthyologist in hopes of learning more about them. I don't understand how an inner core could be preserved if the outer part is also a burrow. It just seems like a filled-in burrow would have been empty inside so that led me to think of concretions instead. 

[DPS Ammonite]

Did you mean ichnologist? If so, what is the name of the ichnologist? I am trying to identify trace fossils from the similarly aged Naco Formation in Arizona.

[BobWill]

45 minutes ago, DPS Ammonite said:

Did you mean ichnologist? If so, what is the name of the ichnologist? I am trying to identify trace fossils from the similarly aged Naco Formation in Arizona.

Ha ha! Yes, of course that's what I meant. He is John-Paul Zonneveld    zonneveld@ualberta.ca

I believe his main focus is tracts but he offered to let me send him samples of these after a fb discussion several months ago. I don't know if he has managed to find the time for such a minor issue and won't bother him for a further response but he is likely to be able to help you or at least have some curiosity about your traces. I believe I found his snail-mail address on the university website.