<Tr> <Td> Pliensbachian </Td> <Td> 190.8 ± 1.0 </Td> </Tr> <Tr> <Td> Sinemurian </Td> <Td> 199.3 ± 0.3 </Td> </Tr> <Tr> <Td> Hettangian </Td> <Td> 201.3 ± 0.2 </Td> </Tr> <Tr> <Td> Triassic </Td> <Td> Late </Td> <Td> Rhaetian </Td> <Td> Archosaurs dominant on land as dinosaurs, in the oceans as Ichthyosaurs and nothosaurs, and in the air as pterosaurs . Cynodonts become smaller and more mammal - like, while first mammals and crocodilia appear . Dicroidium flora common on land . Many large aquatic temnospondyl amphibians . Ceratitic ammonoids extremely common . Modern corals and teleost fish appear, as do many modern insect clades . Andean Orogeny in South America . Cimmerian Orogeny in Asia . Rangitata Orogeny begins in New Zealand . Hunter - Bowen Orogeny in Northern Australia, Queensland and New South Wales ends, (c. 260--225 Ma) </Td> <Td> ~ 208.5 </Td> </Tr>

How does the geologic time scale organize our earth’s history