Stone

[Amra]

I found this one 15 years ago, in the woods on a stone cliff in Bosnia and Herzegovina.   Anyone has any ideas about this, I’ll be thankful 

[Fossildude19]

These look like bivalves or brachiopods in cross section.

This is a concreted, nodular mass of shells.

[Rockwood]

1 hour ago, Fossildude19 said:

bivalves or brachiopods

The fact that it is so difficult to find a definite indication could tilt it a tad toward bivalve ?

[Fossildude19]

I think it may be both, as I see uneven and even sized valves. 

[supertramp]

not sure, but take a look here

ciao

[todor.dbk]

Hi, I think some bivalves are more likely, the shells seem to me to be very symmetrical in cross-section. That's why I'm rooting for shells... Mine could be the same, but in my case they're a bit rougher or thicker, but i think they are also some bivalves .. I have more pictures... Very interesting! unfortunately I know very little :-)

 

 

[abyssunder]

Accordind to the location and possible geological times, I think there are bivalves in the "rock" with erosional features.