Here is a green alga fossil called  Palaeonitella sp.  (Kidston & Lang, 1921). It existed in the Devonian Period (417-354 million year...

  Here is a horn coral fossil called  Streptelasma corniculum   (Hall, 1847). It existed in the Ordovician Period (490-443 million years ago...

  Here is a coral fossil called  Calapoecia huronensis   (Billings, 1865). It existed in the Ordovician Period (490-443 million years ago). ...