Fossil Id--Wing Or Fin?

[Chrisalyne]

This specimen was found in a gravel driveway in Texas outside of Yorktown. It is of unknown location. However, gravel isn't imported into Texas, Therefore, it came from somewhere in texas. The rock was already split open and specimen was laying on the ground. Me and my cousin (he's the one that found it) cannot tell if it is a Wing or a Fin? If it was my guess it would be from the Devonian into the Carboniferous Periods.

Edited May 24, 2014 by Chrisalyne

[Chrisalyne]

here are more pictures of it!

[Sélacien34]

I think that it's a wing. What are the dimensions?

Edited May 24, 2014 by Sélacien34

[quietfocus]

It is a beautiful piece either way. Have you ruled out that it is part of a bivalve?

[JohnJ]

It isn't a wing at all; but it sure looks like one. Your chert gravels around Yorktown weathered from the limestones in Central Texas. Many of those cherts originated in the lower Cretaceous Edwards formation, so it is likely that your fossil is mold of a partial Chondrodonta sp. oyster, Lima sp., or similar bivalve.

Edited May 24, 2014 by JohnJ

[Sélacien34]

Amazing, very similar indeed.

[Chrisalyne]

I talked to my cousin, and he sent me a picture of the dimention. Hope this helps. it does kinda look like a bivalve. I'm not really sure on the bivalve identification specs. However, it does interestingly look similar to the bivalves i researched. If it is limstone than that would definately make alot of sense if it were a marine species.

[JohnJ]

This fossil is in a chert nodule that was formed in limestone.

[Chrisalyne]

Awesome! I would of never guessed it was chert. My guess was a type if sandstone. This is really awesome! We are excited!

[JohnJ]

If he looks at the rock under magnification, it is very likely that other marine fossils will be visible in cross-section perspectives.

[Chrisalyne]

That's so awesome. I'm gonna let him know that, and I believe other fossils were found in that same driveway months back. I think another trip is definitely in order! Thank you!!

[Chrisalyne]

I do know there is a lot of small fossils that can be found in limestone like chrinoids and other marine life. Now that I look back I remember in one of my Geology classes we we collected rocks from an outcrop brought them to the lab and identified them. Then we did a geological map of rock composition and compared it to the charts we made of our samples (random sampling of a 1×1 area) and we had to write a paper on which rocks were likely brought here from glaciers. It was awesome and we found some really awesome rocks from the Canadian shield brought down and deposited from the glaciers (exposed Cambrian rocks). Anyhow, I remember my samples were primary chert. Then my instructor told me it derives from limestone (she explained the process). So thank you for adding that John, because I completely forgot about that until you had mentioned it.

Edited May 24, 2014 by Chrisalyne