Greetings Explorers! The earth has an incredibly long history, as it formed 4,600 million years ago. Geologists divide the passage of time into huge chunks called eras. The giant dinosaurs lived on the earth in the Mesozoic era. Here are some of the most common dinosaurs: T. Rex - The T. Rex had awesome curved teeth each as long as a human hand! Altogether it had 58 of these lethal, pointed weapons. Velociraptor - The Aggressive and speedy Velociraptor was a formidable predator. Although small it was armed with razor-sharp teeth and terrifying dagger-like claws Triceratops - Built like a rhinoceros Triceratops is one of the best-known dinosaurs. It belongs to a group known as the "horned-face dinosaurs". ...