Conodont—minute tooth-like fossils found in certain [Paleozoic] rocks; their origin is not definitely known, but they may have been part of some type of extinct fish.
Coral—bottom-dwelling marine invertebrate that secretes [calcareous] hard parts; member of class Anthozoa, [phylum] Coelenterata.
Corallite—the skeleton formed by an individual [coral] animal; may be [solitary] or form part of a colony.
Corallum—the skeleton of a [coral] colony.
Corona—crown; in echinoids the main part of the skeleton consisting of symmetrically arranged [calcareous] plates.
Coprolite—the [fossil] excrement of animals.
Correlation—the process of demonstrating that certain strata are closely related to each other or that they are stratigraphic equivalents.
Cretaceous—the third and last [period] of the [Mesozoic] era.
Cystoid—an extinct stemmed [echinoderm] with [calyx] composed of numerous irregularly arranged plates; member of class Cystoidea.
Dendritic—resembling a tree, branching.