First one was theorized to be a gerastos trilobite, but I am unsure after comparing images   The second image came with a note that said pachycephalosaurus vertebrae, hell creek. I don't know how accurate that is but if someone could at least tell me what type of vertebrae this is because all the ones I looked up were not this intricate   Third and fourth one I have no idea what they are they never had any notes attached when I unpacked. I completely understand if nobody can