This Specimen has been sold.
2.3" Marston Magna Ammonite Cluster
This is a cluster of Promicroceras marstonense ammonite fossils from Marston Magna, Somerset, England. The ammonites are of the species Promicroceras marstonense and are Lower Jurassic (~200 million years old) in age. The back has been sawed flat and several ammonites can be seen on cross-section.
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. The last lineages disappeared 65 million years ago at the end of the Cretaceous.