Ammonites are an extinct group of marine animals of the subclass Ammonoidea in the class Cephalopoda, phylum Mollusca. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods.
Ammonites' closest living relative is probably not the modern Nautilus (which they outwardly resemble), but rather the subclass Coleoidea (octopus, squid, and cuttlefish). Their fossil shells usually take the form of planispirals, although there were some helically-spiraled and non-spiraled forms (known as "heteromorphs").
Ammonites were some of the first creatures to inhabit planet Earth, and, as such, are an amazing piece to own and display in the home.
MORE AMMONITES, INCLUDING LARGER SPECIMENS, CAN BE FOUND UNDER THE HEADING
"SCULPTURAL ARTWORKS". PLEASE CHECK THEM OUT ALSO.