Is this a fossil?

[Rosemary]

Is this a fossil?

Kosciusko Co, northcentral Indiana

 

[Fossildude19]

We'll need pictures of all 4 sides, top, and bottom.  

Preferably laid flat on a table with a ruler for scale. 

[Rosemary]

[Rosemary]

[Rosemary]

[fifbrindacier]

It's probably some kind of sponge, but i'm waiting for the photos Fossildude asked to be sure.

[oilshale]

Yep, I would guess worn shell.

[fifbrindacier]

I really think this is a sponge, maybe an Hexactinelid one like Brachiospongia for example (i'm not saying this is one here).

I don't think this is a worn shell.

https://www.uky.edu/KGS/fossils/fossil-sponges.php

@Spongy Joe ?

[abyssunder]

This is just a joke (mine).

 

[ClearLake]

My first thought was also a cross section of some shell (brachiopod) but I couldn’t come up with which one it might be.  But I think @fifbrindacier is on to something.  I was not familiar with that sponge, but it does look like it could fit the bill.  I’ll be interested to see if others that are familiar with it think that is a good choice.  Good eye, Sophie!

[fifbrindacier]

18 minutes ago, ClearLake said:

My first thought was also a cross section of some shell (brachiopod) but I couldn’t come up with which one it might be.  But I think @fifbrindacier is on to something.  I was not familiar with that sponge, but it does look like it could fit the bill.  I’ll be interested to see if others that are familiar with it think that is a good choice.  Good eye, Sophie!

Thank you.