Jurassic
The Jurassic period of the Mesozoic Era dated from 203 million years ago to 146 million years ago, after the Triassic and preceding the Cretaceous period. It is named for the Jura mountains between France and Switzerland, which contain many rocks laid down during this period. At this time the supercontinent of Pangaea began to rotate and break apart, and the southern supercontinent of Gondwanaland also began to split.[1]
The period was characterised by a warmer and wetter climate than that of the preceding Triassic, and was dominated by dinosaurs. Notable Jurassic species included Stegosaurus, Allosaurus, Igaunodon, Hypsilophodon and huge sauropods such as Diplodocus, Brachiosaurus and Apatosaurus. The air was ruled by pterosaurs such as Dimetrodon and Rhamphorhynchus, and the first birds, such as Archaeopteryx, appeared during the period.
In the warm oceans, marine reptiles including plesiosaurs and ichthyosaurs were the top predators. The extinct cephalopod ammonites and belemnites were common.
Flowering plants had not yet evolved, and the dominant flora were conifers, ferns, horsetails and especially cycads, some of which grew to the size of modern trees.
Young earth creationist view
Young earth creationists believe that the evolutionary geological timescale is in error and do not believe in the Jurassic period.