3" Ammonite (Promicroceras) Cluster - Marston Magna, England

This is a 3" wide 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 site that produces this material is no longer accessible. Because of this, these specimens are becoming increasingly harder to obtain. The piece has been painstakingly prepared with mechanical tools to expose all of the individual ammonite fossils.

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.
What an ammonite would have looked like while alive.
Promicroceras marstonense
Marston Magna, Somerset, England
Obtusum Zone
Rock: 3 x 2"
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