Sponge Or Coral? What Do You Guys Think? - Fossil ID - The Fossil Forum
Found in middle Tennesee, Not sure exactly if it's some sort of fossilized sponge or coral. It seemed to have some sort of stem or attachment on the bottom. : r/fossilid
sponge fossil | Fossil Lady
Fossil reefs
Wooster's Fossil of the Week: A Recent Sponge Boring from South Carolina | Wooster Geologists
Louisville Fossils and Beyond: Montastrea Coral Fossil
Coral or Sponge? - Fossil ID - The Fossil Forum
Sponge Coral? - Fossil ID - The Fossil Forum
fossil identification by shape
Coral Fossil group 5 including 2 Siderastrea specimens and a sponge Florida USA from Fossils4sale who are a specialist preparer and retailer of high quality fossils, minerals, ammonites and gemstone jewellery.