Permian Period, the geologic period that began about 280,000,000 years ago and lasted 55,000,000 years. It is named for Perm, Russia, where rocks of the period were first studied systematically. The Appalachian and Ural mountains were formed during the Permian Period, and the colorful red rocks of the southwestern United States are mostly of Permian age.
When they discover dinosaur remains, how do scientists know whether they found a male or a female? Would you believe it all comes down to one bone?
Every time a new fossil is found, one of the first things scientists determine is how old that fossil really is. But how do they determine it, and how can they be completely accurate?