Authenticity of some invertebrate fossils

[Vytis]

I recently was given some fossils and just wanted to know their authenticity. I took two pictures of each fossil at different positions (not sure what the clam looking one could be). This is my first time on the forum, and I am looking forwards to also sharing some of my Midwestern and Lithuanian finds in the future. 

[A.C.]

All look legit to me. All of these are relatively common so it wouldn’t make economic sense to go to the hassle of faking them.

[jhw]

As said, real and relatively common specimens. Calymene trilobite, Brachiopod, Belemnite and Ammonite.

[Vytis]

11 minutes ago, A.C. said:

All look legit to me. All of these are relatively common so it wouldn’t make economic sense to go to the hassle of faking them.

Thanks for the reply, that was good to know. The one I was mainly concerned was the trilobite as I had never seen one that white before. The ones I've found previously were all brownish/blackish. 

[Kane]

14 minutes ago, Vytis said:

Thanks for the reply, that was good to know. The one I was mainly concerned was the trilobite as I had never seen one that white before. The ones I've found previously were all brownish/blackish. 

The Gravicalymene celebra from Illinois typically appear as steinkerns, taking on the very light beige colour of the matrix.

[JBkansas]

21 hours ago, Kane said:

The Gravicalymene celebra from Illinois typically appear as steinkerns, taking on the very light beige colour of the matrix.

I wondered about the trilo mortality plates that are matrix colored. It would make sense that they're are just mold/casts.