Things You'll Need
Instructions
If the fossil doesn't show any signs of a spine, or backbone, it's most likely an invertebrate. Invertebrate fossils make up the majority of the found fossils. These can be the outer shell of prehistoric lobsters, crabs and shrimp.
Note fossils with multiple holes and that appear porous. These may be the remains of a sponge.
Look for fossils in the shape of a flower. These are most often echinoderms (starfish, sea urchins, crinoids). Fossils in the shape of a shell are likely brachiopods (similar to the clam and now mostly extinct).
If the fossil has a spine, it may be a fish. All fish have a backbone.
Note any bones, jaw line or even teeth seen within the fossil. In many fossils of this kind (if the fossil is intact) the bones and skeleton of the fish are very visible.