3.85" Pristine Fossil Ammonite (Hoploscaphites) - South Dakota

Pristine Fossil Ammonite (Hoploscaphites) - South Dakota #209665

This is a 3.85" wide ammonite (Hoploscaphities spedini) specimen collected from the Fox Hills Formation of South Dakota. It has been exquisitely prepped, showing little signs of restoration. The color of the shell is enhanced by the insane amount of natural detail, including the raised bumps on the outer ridges that are characteristic of the Hoploscaphites genus.

This specimen is remounted to the rock it was found in, which was cut flat for sturdy and convenient display.

These 70 million year old ammonites lived when South Dakota was a shallow inland sea. They were found preserved in concretions when split open. They then had to be hand-prepared to remove the hard rock surrounding them from their shells, a very time consuming task.

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.

More about ammonites