As sediment continued to settle on top and turn to rock, water moving through the rock slowly replaced the chemicals in the bones with hard minerals, creating fossils. OK, so you need to look for sedimentary rock. But sedimentary rock has been around for millions and millions of years. You need to find the sedimentary rock that formed during the time the dinosaurs lived. Dinosaurs roamed the Earth between 250 million years ago and 65 million years ago.
Geologists divide the Earth's history into sections called eras.
Click on the era that spans the time when dinosaurs lived .