I thought it was a piece of concrete at first....

[Benjaminpb]

I found this in a creek bed here in Austin Texas.

I moved it because I thought it was a piece of concrete and it was in the way of me looking through the gravel bar. Then I noticed the weird honeycomb patterns. Actually it's more like a big honey comb. It looks kind of like a filter so I'm assuming it's some sort of filter feeder. Am I way off? Any ideas? Thank's!

[Kane]

I think you found a tabulate/colonial coral. Nice find!

[Benjaminpb]

[FossilDAWG]

It's a rudist, not a coral.  

 

Don

[Kane]

1 minute ago, FossilDAWG said:

It's a rudist, not a coral.  

 

Don

Ah, now that I see a few more pictures, it is indeed a rudist! Good call, Don.

[FossilDAWG]

If I only saw the first photo, I would have suggested a coral as well.  The porous structure of the rudist shell can indeed look like a tabulate coral.  However that would be quite unexpected in an area of Cretaceous rocks, far from any Paleozoic outcrops.

 

Here is a thread with a good discussion of a very similar fossil from the same area.

 

Don

 

 

[Benjaminpb]

Thanks!

I have a bunch of small rudists but I've never seen one like this. Are there different species?

I'm curious about why it's so big.

Nm, didn't see the link. 

[FranzBernhard]

Could this be Durania austinensis?