<Tr> <Td> Sea level (above present day) </Td> <Td> Relatively constant at 60 m (200 ft) in early Permian; plummeting during the middle Permian to a constant − 20 m (− 66 ft) in the late Permian . </Td> </Tr> <Tr> <Td_colspan="2"> Key events in the Permian view discuss edit - 300---- - 295---- - 290---- - 285---- - 280---- - 275---- - 270---- - 265---- - 260---- - 255---- - 250--l o z o i Carboni - ferous i s u r l i n u d l u p i n o p i n g i n Asselian Sakmarian Artinskian Kungurian Roadian Wordian Capitanian Wuchiapingian Changhsingian Triassic ← Mass extinction r m i n An approximate timescale of key Permian events . Axis scale: millions of years ago . </Td> </Tr> <P> The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic period 251.902 Mya . It is the last period of the Paleozoic era; the following Triassic period belongs to the Mesozoic era . The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm . </P> <P> The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles, lepidosaurs, and archosaurs . The world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa . The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior . Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors . </P>

When did the permian period begin and end