Fossilized seashells identification

[Nat006]

Hello everyone,

 

I visited a beach in the Netherlands and I collected some things that I thought had the chance to be fossilized. I want to ask if the next specimens in the pictures I will post are fossilized seashells, modern ones, just rocks? And what kind of seashells they are in case they are fossilized. Thank you! I will post them separately in the replies.

[Nat006]

#1

Is this fossilized? Or just some seashell caught up in slag or something?

[Nat006]

#2

This one is weird, I would say it's just a rock but it has a certain shape to it? Almost like a shell but something is off. What is this?

[Nat006]

#3

 

Two different but similar specimens. They look and feel fossilized but I saw there is a certain modern seashell that looks like this so I don't know.

[Nat006]

#4. Caught in matrix but looks translucent. Fossil or just caught up in some concrete? 

[Nat006]

That's all