4.85" Polished Ammonite (Promicroceras) Cluster - Marston Magna

Polished Ammonite (Promicroceras) Cluster - Marston Magna #207732

This is a 4.85" tall stone containing many small ammonite fossils. The ammonites are of the species Promicroceras marstonense and are Lower Jurassic (~200 million years old) in age. This rock is quarried near Marston Magna, Somerset, England. Locally this ammonite filled rock is known as "Marston Marble".

The piece has been painstakingly prepared with mechanical tools to expose all of the individual ammonite fossils on one side. The opposing face was polished to a glossy finish revealing intriguing ammonite cross-sections within the rock. The base is cut flat to stand unassisted without the need for a display stand.

About Ammonites

Ammonites were ancient marine cephalopods, similar to today's squids and octopuses, but with a defining feature: their distinctive, tightly coiled spiral shells. These shells, resembling those of modern nautiluses, served as both a protective home and a buoyancy aid, allowing ammonites to navigate the prehistoric seas with ease. First emerging around 240 million years ago in the Triassic Period, ammonites thrived for over 175 million years, adapting through numerous forms and sizes. As predatory creatures, they likely fed on smaller marine organisms, using their tentacles to capture prey. However, their long reign came to an end 65 million years ago at the close of the Cretaceous, coinciding with the mass extinction event that also eliminated the dinosaurs.

What an ammonite would have looked like while alive.