4.4" Agatized Belemnite Fossil - England

This is an agatized Belemnite (Cylindroteuthis pusoziana) fossil collected from the Oxford Clay of England. It's Middle Jurassic, Callovian Stage or approximately 160 million years old.

Belemnites are probably the most well known extinct cephalopod after the ammonites. They lived during the Jurassic and Cretaceous periods and are fairly common fossils found throughout the world. They had a hard, internal, cone shaped structure that is often preserved as a fossil though it is not technically a shell. They had 10 arms but unlike modern squid these arms had small hooks instead of suckers.