Nautiloid (round) and tooth from Trinity river

[Lone Hunter]

This was my first trip to Trinity river in Tarrant co.,  this section was close to borders of QT and QAL and didn't know what to expect.  I certainly didn't expect to lift up rock and find a Nautiloid/Nautilus still soft in the marl.  Have no idea what the marl was or how to determine age of this. Only prepped it a little afraid to mess it up.  Tooth from same place and hesitant to call it bison since they're always bovid. 

[Rockwood]

I'm sort of on record as seconding, if not suggesting, these IDs. It'd be nice to think they are correct.

 Might make up for flubbing the recent ammonite/rudist thing. 

[Al Dente]

7 hours ago, Lone Hunter said:

I certainly didn't expect to lift up rock and find a Nautiloid/Nautilus still soft in the marl.  Have no idea what the marl was or how to determine age of this. Only prepped it a little afraid to mess it up.

 

This is really odd for Tarrant County Texas. Was this found in outcrop or loose in the stream gravel? The closest match I can find is with the Paleogene genus Hercoglossa or possibly Cimomia. I don't believe there are any Paleogene outcrops in the area. Collectors from the area would know for sure. Another possibility is a Paleozoic goniatite but the sutures face the wrong direction. If it were a goniatite, I would suggest it washed quite a distance downstream. Here's a picture of Hercoglossa. 

 

 

[Captcrunch227]

Not an expert on this, but I've found these several times and am told they're some kind of bovine. Cow, buffalo, bison, etc. 

 

I'm not much help on the nautiloid here, but to my knowledge the only species of nautiloids in Texas during the Cretaceous are Cymatoceras.  

[Al Dente]

1 hour ago, Captcrunch227 said:

Not an expert on this, but I've found these several times and am told they're some kind of bovine. Cow, buffalo, bison, etc. 

 

I'm not much help on the nautiloid here, but to my knowledge the only species of nautiloids in Texas during the Cretaceous are Cymatoceras.  

 

 

Paracymatoceras texanum from this publication looks like a match. The one in the illustration is from Sycamore Creek in Ft. Worth.

edit: I quoted Captcrunch227 because his suggestion of Cymatoceras led me to this article.

 

Edited January 19, 2022 by Al Dente

[Lone Hunter]

8 hours ago, Al Dente said:

 

This is really odd for Tarrant County Texas. Was this found in outcrop or loose in the stream gravel? The closest match I can find is with the Paleogene genus Hercoglossa or possibly Cimomia. I don't believe there are any Paleogene outcrops in the area. Collectors from the area would know for sure. Another possibility is a Paleozoic goniatite but the sutures face the wrong direction. If it were a goniatite, I would suggest it washed quite a distance downstream. Here's a picture of Hercoglossa. 

 

 

I plucked this out of the marl that was exposed due to low water level,  the marl looks similar to Eagle Ford.  This does look like Paracymatoceras texanum and I'm thrilled to have found it!