Hoploscaphites Ammonite Cluster- South Dakota

These are two nice sized Hoploscaphities nicolletii ammonites as well as two Hoploscaphities (Jeletzkytes) spedeni, collected from the Fox Hills Formation of South Dakota. They have been wonderfully prepared in the hard concretion they were found in. The matrix has been prepared in such a way that the four ammonites display nicely without the use of a stand.

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.