Flexi Says: There are many layers of rock on the Earth's surface. Newer layers form on top of the older layers; the deepest rock layers are the oldest. Therefore, you can tell how old a fossil is by observing which layer of rock it was found. The fossils and the order in which fossils appear is called the fossil record. Generally, paleontologists look for fossils on the surface exposed to air without much digging. However, a dinosaur fossil was discovered in Norway at a depth of 2.3 km, which is the deepest discovered fossil.
