7" Marston Magna Ammonite Cluster - Polished on Back

This is a very cool plate of small ammonite fossils from Marston Magna, Somerset, England. On one side of the plate, the ammonites have been prepared from the rock, and the back side has been cut and polished to reveal the ammonites in cross-section. The ammonites are of the species Promicroceras marstonense and are Lower Jurassic (~200 million years old) in age. This rock is quarried from near Marston Magna, Somerset, England and by slicing and polishing it the beautiful inner chamber detail of the ammonites can be seen.

The polished face is 7x4.3" and the rock varies in thickness, up to 1.1" thick. It comes with an acrylic display 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. 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.

What an ammonite would have looked like while alive.
What an ammonite would have looked like while alive.
Promicroceras marstonense
Marston Magna, Somerset, England
Lower Lias, Obtusum Zone
7" wide, 4.3" tall
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