This Solitary Rugose Coral is from the Silurian.
http://fossilsaustralia.com/solitary-rugose-coral-4/
http://en.wikipedia.org/wiki/Rugose_coral
Fossils of Australia
This Solitary Rugose Coral is from the Silurian.
http://fossilsaustralia.com/solitary-rugose-coral-4/
http://en.wikipedia.org/wiki/Rugose_coral