6.8" Jurassic Ammonite (Stephanoceras) Fossil - England
This is a large, 6.8" wide Stephanoceras humphresianum ammonite fossil from Dorset, England. It is Middle Jurassic in age, or approximately 168 million years old. It has been mostly prepped free from the rock it was found in and one edge has been cut flat for presentation purposes.
Ammonites were predatory mollusks that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. True ammonites appeared in the fossil record about 240 million years ago. The last lineages disappeared 65 million years ago at the end of the Cretaceous.