Help with ammonite identification

[SL0327]

Hi there, I found a fossil trace that appears to be from an ammonite on our west Texas ranch and what appears to be dinosaur tracks a few miles away as well. Can anyone identify more if this an ammonite trace and what kind from this photo? Thank you in advance.

Edited January 21, 2020 by SL0327

[Fossildude19]

Welcome to the Forum.  

 

Definitely an ammonite. Not sure we can identify it with such a tiny photo. 

I've taken the liberty of enlarging, brightening, and enhancing the photo.   

 

 

Maybe some of our Texas friends can weigh in. 

 

@JohnJ  @grandpa  @erose   @DPS Ammonite  @BobWill  @Uncle Siphuncle

[Uncle Siphuncle]

The better the provenance, the better the ID.

[grandpa]

Hello and a warm welcome to TFF from Austin.  Sure looks like an ammonite alright.  Can we get a better picture, closeup.  Also, to paraphrase Uncle S. above, W. Tx. is a large area with many ages of formations exposed.  If you could narrow the location down considerably (e.g., NW corner of County ________) we could get a much better idea of the age of the fossil and thus the ID.

 

You have certainly come to the right place for such answers, we just need a bit more info to be helpful.  Again, welcome.

[Ludwigia]

Welcome to you and your ammonite impression from Germany.

[SL0327]

It was found in in Val Verde County in Langtry, Texas.

[grandpa]

So SLO, here's the deal:

 

The area immediately around Langtry (bounded by Langtry Creek on the west and Eagle Nest Creek on the east) has a few exposures of different ages.   One would need to know exactly where the ammo was found to know the age, esp since ammos are such good index fossils and vary across the different formations. 

 

For example, on a N-S vector, the town itself sits right on the border of Washata Group, Buda fm. to the north and Fredericksburg Group, Devil's River fm. to the south towards the Rio Grande.  Both are Lower Cretaceous - one early and one late.  About 2 mi north of Langtry the exposure changes to Gulfian Series, Terlingua Group, Boquillas fm.  A couple more miles north and you run into some Austin Chalk (Gulfian) exposures with their own unique fauna. Both of these formations are Upper Cretaceous. 

 

So the area around Langtry offers a nice buffet of formations and exposures to consider, each with its own unique (and of course some common) ammonite fauna.  If you could be a bit more specific than "Langtry" as to the location, we might be able to better nail down the age of the exposure that the ammo came out of and thus better able to ID the ammonite.

 

Or, you could look at the geological map on your own and find the age of the area you were in.  Go to:  https://txpub.usgs.gov/txgeology/

 

BTW, the geological diversity around Langtry makes it a great place to find a variety of lower and upper Cretaceous fossils. 

 

Hope this helps,

 

Grandpa
 

[BobWill]

Welcome from North Texas. Thanks for posting your ammonite. I hope the folks down your way can give it a name. Just to clarify the terms we use, your fossil would not be considered a trace fossil. Wikipedia can help explain how that tern is used. Your fossil is almost certainly an internal mold. If we can get a better image that can be confirmed.