2" Hoplocaphites Ammonite Cluster - South Dakota

This is an aesthetic cluster of Hoploscaphites nodosus ammonites from the Fox Hills Formation of South Dakota. There are four ammonites present with the largest being 2" wide. They have been nicely prepared from the surrounding limestone, and the rock sits nicely on a flat surface for display. There are many micro fossils embedded around the cluster such as small clam and gastropods. This particular cluster has part of a small baculite directly under the ammonite.

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.