History of Earth the late Paleozoic. The Mesozoic ("middle life") era lasted from 251 Ma to Ma. It is subdivided into the Triassic, Jurassic, and Cretaceous periods. The era began with the Permian–Triassic extinction event, the most severe extinction event in the fossil record; 95% of the species on Earth died out. It ended with the Cretaceous–Paleogene extinction event that wiped out the dinosaurs.. The Cenozoic ("new life") era began at Ma, and is subdivided into the Paleogene, Neogene, and Quaternary periods. These three periods are further split into seven sub-divisions, with the Paleogene composed of The Paleocene, Eocene, and Oligocene, the Neogene
Partridge Island (Nova Scotia) geological period between 208 and 220 million years ago, rivers swollen by intense rains carried coarse sediments (now sedimentary rocks) from nearby highlands into the Fundy Basin. Other deposits came from wind-blown sand dunes. Later, large lakes formed on the central part of the basin depositing finer sediments up to 1,000 metres thick and, as they dried up periodically, they left behind salt and gypsum deposits. The red sedimentary sandstone base of Partridge Island dates from the late Triassic period. The covering layer of dark basalt was formed from magma and lava eruptions in the Jurassic period between 175 and