Ключевые слова: age, animals, archaeological, archeology, background, biology, cambrian, cenozoic, closeup, earth, era, evolution, excavation, fossil, fossil stone, fossils, geologic, geological, geology, limestone, marine, paleozoic, period, plant, prehistoric, rock, science, sea, spiral, stone, time, trilobite, trilobite fossil, trilobite fossils, trilobites,