A period of great transformation, the Late Cretaceous Period is when the dinosaurs disappeared from the earth. Learn more about the Late Cretaceous dinosaurs that existed during this era, such as the Tyrannosaurus, Gallimimus, and Brachylophosaurus.
In 1914, Barnum Brown of the American Museum of Natural History collected a nine-inch-long skull and some foot bones from the Judith River Formation in Alberta. It was named Dromaeosaurus, which means "running reptile." Learn more about the Dromaeosaurus.