Fossilization

There are an incredibly immense number of ways that a specimen can get fossilized.

Fossilization from Ted Rogers on Vimeo.

The most commonly preserved fossils out there are teeth. Teeth are pretty durable objects due to their enamel coating.

Prior to the Renaissance, it was commonly thought that fossilized shark teeth were the petrified tongues of dragons. In 1666, Danish Geologist and Anatomist Nicolas Steno figured out what was really going on with these pointy rocks after a detailed study of a shark's head.