Lake Jacksboro TX PSoA Field Trip

[JamieLynn]

The Paleontological Society of Austin gets to go to the Lake Jacksboro site once a year.. Dallas Society also goes out there, so we try to make sure not to overlap, but surprisingly, the site is so productive, there's always great stuff to find! The Carboniferous Period- Pennsylvanian site is well known for its wide variety of fauna. I've been out there a dozen times and almost every time I find something new!  It may seem a bit desolate, but it's worth the trek! 

 

 

My first happy find was a crinoid calyx. As with most Pennsylvanian sites, crinoids are prolific.  But I've not found much complete crinoid material...but this time, I found two!  

 

Another fossil that is a special find out there is a little thing called a Rostroconch.  It was originally thought to be a bivalve, but has been given it's own class. 

This is only the third one I've found. They are not common. 

Another of the most sought after fossils there are the Goniatites and Nautiloids. The big ones are rarely found whole, but you can also find tiny ones in the micro zone. Gonioloboceras and Tainoceras are the most common largeish ones and I have yet to find a GOOD complete one of either. I have found a few Gonioloboceras what were either almost whole or were so weathered that they look like zombies! This time I THOUGHT I had finally found a good complete one! This is what I saw and my heart did a flip flop! 

 

 

Unfortunately when I cleaned it up, the center was eroded but I actually kind of like the other side, even though it is weathered and a little "zombified" at least it's mostly whole! But the zigzag sutures are amazing! 

 

I found a few smaller ones in the field, but the big payday was the  two 5 gallon buckets of micro matrix I brought home with me from the micro zone and found a PLETHORA of tiny goniatites this time! 

Top Row- R: Glaphyrites millsi    C: Imitoceras grahamensis     L: Neodimorphoceras texanum

Bottom Row: Prouddenites grafordensis     C: Wiedeyoceras pingue      L: Unknown

 

 

 

But this is kind of fascinating - it was encased in a little bit of matrix, so I tried to break it off but ended up kind of breaking the whole thing. But because of that, it released the tiny interior!   Peritrochia sp.

 

 

I certainly wish it were whole, but it's still fascinating to see the interior.

Another new find was this little Brachiopod Fimbrinia - I'd been looking for one of these for a while and finally found one! 

 

Another nice little Brach with a surprising pearlescent surface - Kozlowskia splendens

 

Also found this little Orbiculoidea missouriensis 

Here is an unusual coral called  Palaeacis perpendicularis 

 

 

Found lots of cool gastropods, but my all time favorite is Cymatospira montfortianus

 

 

 

 

I am already excited about getting back out there, maybe in the Fall because Texas summertime is NOT when you want to be out on those flats! 

 

 

 

 

[Fossildude19]

Wonderful report and Lovely finds, JamieLynn! Love the Rostroconch and the Nautiloids!

Great gastropods, too! 
Thanks for the trip report!

[Mikrogeophagus]

Looks like a lot of fun! I think the rostroconch takes the cake. Cool to see some micros out of there. I've always wondered if conodont elements could be found in that matrix.

[Collector9658]

Very cool and pretty finds. Thanks for sharing.

[Missourian]

Beautiful finds, especially the ammonoids! Intact Gonioloboceras seem to be quite rare.

[JamieLynn]

@Mikrogeophagus  I was definitely looking for conodonts, but I've never found any, so it's possible I missed them, even though I generally "know" what to look for. But I think I would have noticed them if there were any...at least I hope I would! 

[FossilNerd]

Great report and finds JamieLynn! So much good stuff! I didn’t realize rostroconches could be found in the Carboniferous. Very cool! 
 

 

[Darktooth]

Great finds Jamie, the site appears to be a great place to collect!

[JohnJ]

Very nice images, and congratulations on your new finds!

[Jeffrey P]

Jacksboro is possibly my favorite site I've ever been to- for its abundance, wonderful preservation, and biodiversity. Your collection there certainly reflects that. I especially love the rostroconch and the micro goniatites. Excellent stuff! Big congratulations and thanks for sharing them.