3.4" Polished Ammonite (Promicroceras) Section - Somerset, England

Polished Ammonite (Promicroceras) Section - Somerset, England #211318

This is a polished section of rock containing many small ammonite fossils, often referred to as "Marston Magna Marble". The ammonites are of the species Promicroceras marstonense and are Lower Jurassic (~3.400 million years old) in age. This rock is quarried near Marston Magna, Somerset, England and by slicing and polishing it, the beautiful inner chamber detail of the ammonites can be seen.

One side of this specimen has been polished to a glossy finish, with the rest of the specimen left in its rough state, featuring exposed ammonites.

Ammonites were predatory cephalopod mollusks that resembled squids with spiral shells. They are more closely related to living octopuses, though their shells resemble that of nautilus species. True ammonites appeared in the fossil record about 240 million years ago during the Triassic Period. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

What an ammonite would have looked like while alive.