1.75" Fossil Nautilus (Eutrephoceras) in Limestone - South Dakota

Fossil Nautilus (Eutrephoceras) in Limestone - South Dakota #155427

This is a beautiful, 1.75" wide fossil Nautilus (Eutrephoceras) from the Fox Hills Formation of South Dakota. It has been prepared free of the hard concretion it was found in, with a small portion still connected with the rock, allowing for aesthetic presentation.

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.

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