Jurassic Museum of Asturias display in separate cabinets. In the Pre-Mesozoic hall, the exhibits relate to the time from the creation of the Earth 4500 million years ago to the Palaeozoic age, 251 million years ago with displays of first organisms on the Earth, evolution process of fossils and their dating, classification of the vertebrates and their inherited relations, deterioration and extinction of nearly 95% of these systems by end of the Palaeozoic period. In the hall representing the Cretaceous period, which is the last period of the Mesozoic era from 145 to 66 million years ago, the displays relate to the biological and
Geological period example the 'Jurassic System' of rocks was formed during the 'Jurassic Period' (between 201 and 145 million years ago). The following table includes all currently recognized periods. The table omits the time before 2500 million years ago, which is not divided into periods. See Geologic time scale#Proposed Precambrian timeline for another set of periods 4600–541 MYA. In a steady effort ongoing since 1974, the International Commission on Stratigraphy has been working to correlate the world's local stratigraphic record into one uniform planet-wide benchmarked system. American geologists have long considered the Mississippian and Pennsylvanian to be periods in their own right