Discoscaphites & Sphenodiscus Ammonites

This is a beautiful association piece of Late Cretaceous ammonites from the Fox Hills Formation. There are 3 Discoscaphites conradi ammonites, 2 Sphenodiscus sp. ammonites and numerous gastropod fossils ont he same piece of matrix. The largest Discoscaphites is 1.8" wide and the entire piece is 3.5" x 3.5" x 2.5"

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.