Pair of mystery fossils from the W. M. Browning Cretaceous Fossil Park

[aplomado]

I wanted to share a pair of mystery fossils found by a  friend at the W. M. Browning Cretaceous Fossil Park in MS.  We were trying to figure out what they were.

Can you all help?

 

The first pair of images are both sides of a very flat fossil.

The rest are of an odd structure.  Does it look like bone to you?  If so, I was wondering if it might be a jaw fragment; it reminds me of one I found before.

[elcoincoin]

Hello,

 

Second one is gastropod internal mold part in my opinion

[old bones]

The first one reminds me of a fish otolith.