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Toothhound

Invertebrate fossils

Shell fossils, ammonites, echinoids, corals, and bryozoans. Often preserved as molds, casts, or replaced minerals rather than original shell.

Detailed entries

Ammonites
Coiled cephalopods that ruled Mesozoic seas alongside the dinosaurs and went extinct with them at the K-Pg boundary 66 million years ago. Complete specimens are rare; most NJ creek finds are fragments of the iridescent inner-shell layer or impressions of the suture pattern in chalk matrix.
Cretaceous oysters
Thick, gnarled oyster shells (typically Exogyra and Pycnodonte) that paved the floor of the Late Cretaceous seaway. Their durable calcite preserves them better than almost any other invertebrate — you'll find them in nearly every Cretaceous creek bed on the East Coast.
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.

Also reported in this category

These show up on location dossiers but don't have a dedicated guide entry yet. Each links to the first site where it's reported.

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