ID on unusual impressions in Cretaceous clay please

[Pearl]

Had a great day getting out this weekend and exploring some cretaceous clay outcroppings along the creek bed.  Lots off impressions of shells but other interesting things that I don't recognize.  Are they anything other than erosion patterns? I have more photos if needed.  Thank you!

 

 

 

ay ge

 

I think the top is some type of shell but what about underneath?

[Pearl]

Adding a couple of photos for size reference.

[supertramp]

I think you have some fracture related structures (fringe cracks, plumose structure...)

ciao

[Pearl]

33 minutes ago, supertramp said:

I think you have some fracture related structures (fringe cracks, plumose structure...)

ciao

Yes!  I looked those up.  Exactly what it looks like.  So cool.  Thanks for getting back to me!  

[Pterygotus]

I think I can also see a brachiopod negative impression.

[Ludwigia]

I concur with supertramp. That impression could also come from either an ammonite or a bivalve.

[Pearl]

20 hours ago, Ludwigia said:

I concur with supertramp. That impression could also come from either an ammonite or a bivalve.

A large oyster perhaps?

[Pearl]

Another strange something

[Ludwigia]

2 hours ago, Pearl said:

A large oyster perhaps?

Inoceramus perhaps. Your new strange something is made up purely of sedimentary stone.

[Plax]

pic 5 could be a trigonia impression and suspect it's a bivalve for sure. Getting a nautiloid feel for the last one but it looks like the clay breaks with a conchoidal fracture which can make for interesting fossil-looking rocks. Pic 3 looks like chert which can have fossils in it if broken open.