Ammonites are perhaps the most widely known fossil, possessing the typically ribbed spiral-form shell. These creatures lived in the seas between 240 – 65 million years ago, when they became extinct along with the dinosaurs.

Orthoceras fossils date back to the Silurian age (400+ million years ago) and are among the earliest forms of life. The name means straight horn, referring to the characteristic long, straight, conical shell.