Huge, 12.5" Fossil Ammonite (Placenticeras) - South Dakota

This is a large ammonite (Placenticeras meeki) that was collected from the Fox Hills Formation of South Dakota. This ammonite was found broken and in some places fragmented requiring gap fill restoration, crack repair and significant stabilization. This stabilization is in the form of a thick epoxy coating on one side, while the opposite side has a thin glazing of epoxy. The remaining shell fragments have colorful iridescent properties.

Comes with a display stand.

These 70 million year old ammonites lived when South Dakota was a shallow inland sea. It was found preserved in a concretion that was split open. It then had to be hand prepared to remove the hard rock surrounding it from the shell, a very time consuming task.

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.
Placenticeras meeki
South Dakota
Fox Hills Formation - Trail City Member
12.5" Wide
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