Beautiful Hoplocaphites Ammonite Cluster - South Dakota

This is an aesthetic cluster of Hoploscaphites spedini ammonites from the Fox Hills Formation of South Dakota. Hoploscaphites spedini is one of the rarer species of Hoploscaphites. There are four ammonites present with the largest being 1.45" wide. They have been nicely prepared from the surrounding limestone, and the rock sits nicely on a flat surface for display.

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.