4.7" Jurassic Ammonite (Hildoceras) - England
This is a 4" Wide Hildoceras bifrons ammonite from Whitby, England. These well preserved ammonites are Jurassic in age and are found in hard concretions that must be split open to reveal the fossil. This comes with a clear acrylic stand.
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. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.