Arizona boasts a great variety of fossils, the best known of which were of creatures that lived during the Triassic Period. These include early dinosaurs and the trees that left us Arizona petrified wood, (Araucarioxylon arizonicum), the state's fossil. Arizona petrified wood is protected in Petrified Forest National Park. Another famous Arizona fossil site is the Grand Canyon. It was carved out of the -------------, a famous geologic region.?