Name: Halysites.
Meaning: River stone.
Grouping: Cnidarian,
Anthozoan, Zoantharian,
Tabulatan, Halysitid.
Informal ID: Chain coral.
Fossil size: 5cm/2in.
Reconstructed size: Typically
10-20cm/4-Sin across.
Habitat: Sea floor.
Time span: Ordovician to
Silurian, 500-410 million
years ago.
Main fossil sites: Worldwide.
Occurrence: •••