Animals having a spinal column, including fish, reptiles and birds. Fossils are generally limited to skeletal remains but sometimes also include cartilage, skin, scales and stomach contents.
Sharks are an old family of fish, dating back many millions of years to the Devonian Period.
They were common predators and scavengers in the Western Interior Sea. Sharks shed their teeth continuously through their life and these isolated teeth are frequently found in the chalk. Their triangular, blade like teeth are the largest found in the chalk and their thin, disk shaped vertebrae are also found . Sometimes the entire shark including skin is preserved as a fossil. A well preserved example of Cretoxyrhina mantelli on display at the Sternberg Museum in Hays, Kansas.