The Jurassic period is part of the geologic system of classifying geologic formations. The Jurassic period is part of the Mesozoic era, and is divided into Lower, Middle, and Upper epochs. The Jurassic is preceded by the Triassic era and followed by the Cretaceous era. The Jurassic was named from the French word (Jurassique) for the Jura mountains of Switzerland. Under the uniformitarian dates assigned by secular geologists, it represents approximately the period of Earth's history from 200 million years ago to 145 million years ago. Flood geologists reject the uniformitarian assumptions behind the dates derived by secular geologists, so they reject these dates (see geologic system). Instead, they would consider most if not all Jurassic strata to be laid during Noah's Flood.Many sediments containing dinosaur fossils are assigned to the Jurassic, which evolutionists believe to be the the peak time of the dinosaurs.