Two different types of shark's teeth

Near the top is a tooth from an ancient relative of modern sharks as we know them today. The rippled flattened tooth below and to the left of it is from a ptychodus. Also called a 'crusher shark', this extinct shark species used it's molar-like teeth to crush and eat oysters that were plentiful at the bottom of the Creataceous western inland waterway that covered all of the southwest some 90 million years ago.

Shark's teeth like these are plentiful and easy to find on top of the ground throughout the tropic shale if you know where to look and what to look for.