Ammonites (biology)

From Conservapedia

Ammonites (Biology)

Ammonites are an extinct group of marine Cephalopod Mollusc, belonging to the subclass Ammonoidea in the class Cephalapoda, which belongs in the phylum Mollusca.

Ammonites are excellent index fossils, that is, their fossils will often give an age to the rock layer in which they are found.

Although Ammonoids were present from the late Silurian, Ammonites were at their height in the Jurassic.