what kind of fossil is made by an imprint?
Fossil: Definition, Types, Characteristics & Examples Mold fossils and cast fossils occur when an organism leaves an imprint that is fossilized. Mold fossils are when an imprint is made and that imprint is fossilized, whereas cast fossils are imprints that are filled in and then fossilized. This is a mold fossil of a bivalve, like a clam or oyster, from a dig sight in Ohio