3.1" Iridescent Hoploscaphites Ammonite - South Dakota

This is a 3.1" wide, iridescent Hoploscaphities comprimus ammonite specimen from the Fox Hills Formation of South Dakota. It's been wonderfully prepared from the hard concretion it was found in. The limestone has been prepared in a way that is displays nicely on a flat surface.

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.