Fossilized bones of a dinosaur, surrounded by sediment, back in the lab.
Sterling (left) and Nathan Smith excavate a new dinosaur in New Mexico.
Sedimentary rocks are formed from layers of sand, silt, dead plants, and animal skeletons.
My first job is to find the fossils. Fossils are found in layers of sedimentary rock. So that's where the team and I go—to places with sedimentary rock. They could be as close as Arizona or as far away as the Gobi Desert in Mongolia!

At the dig site we begin by looking for exposed fossils. When we find something we start digging. We dig slowly and carefully so we don't damage the specimen. Back in the lab, we can study the fossil more closely. Our goal is to determine what kind of animal it was and when it lived.

Want to find out how the history of life is written in the rocks? Let's go!