Unknown 5

Bivalve or Bryozoan? There's so little left it's hard to tell.

Unknown 4

It's either tabulate coral or a strange crystal nugget.

Unknown 3

Unknown 2

Unknown 1

It's either a bit of bryozoan, or a thin slice of tabulate coral. I'm not certain, either way.

Possibly a rugose coral fragment

Mystery fragment yay.

Tiny little thing

It's too small to tell. The whole stone is about 12mm across.