Hey Bigjohnnyblue,
The 3rd and 4th photo look like an algae ball, if you are collecting in the Silurian that is probably what they are. The one next to the pen in the last photo is a cephalopod.
I forgot to mention the first and second photos. The one on the right looks like a fossil sponge the one on the right is coral. Fossil sponges are not all that common due to the having soft bodies. However silicious sponges do sow up as fossils from time to time.
Good hunting
Nomad1