The Permian–Triassic extinction event was an extinction event that occurred approximately 251.9 million years ago, at the boundary between the Permian and Triassic geologic periods, and with them the Paleozoic and Mesozoic eras. From Wikipedia
Fossil evidence reveals the survival of diverse plant ecosystems in Xinjiang, China, before, during, and after the End-Permian Mass Extinction 252 million years ago.
