Invertebrate fossils
Echinoid tests (sand dollars)
Fossil sand dollars and sea biscuits — the calcified skeletons (tests) of extinct echinoids. The five-petal flower pattern on the top side is unmistakable. Eocene through Pliocene worldwide; the Florida Tampa Member produces gorgeous flat Scutella by the bagful.
How to spot it
- ▸Five-petal radial pattern on top is diagnostic
- ▸Light, brittle, often broken — handle gently
- ▸Color is usually pale tan to chalky white
- ▸Underside has a small central mouth opening
- ▸Whole tests are uncommon; partial sectors still display nicely
Reported at these sites
About the category
Shell fossils, ammonites, echinoids, corals, and bryozoans. Often preserved as molds, casts, or replaced minerals rather than original shell.