Excellent 4.8" Hoploscaphites Ammonite - South Dakota

Here is a very robust, 4.8" wide Hoploscaphities nebrascensis ammonite from the Timber Lake Member of the Fox Hills Formation. It has been prepared totally free of matrix.

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.