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
Llandovery epoch Llandovery epoch In the geological timescale, the Llandovery epoch (from 443.7 ± 1.5 million years ago to 428.2 ± 2.3 million years ago) occurred during the Silurian period. The epoch follows the massive Ordovician-Silurian extinction events; the second largest extinction event after the Permian-Triassic extinction event million of years later. The epoch was named after Llandovery in Wales. The Llandovery epoch is subdivided into three stages: Rhuddanian, Aeronian and Telychian. The Lower Llandovery rocks consist of conglomerates, sandstones and slaty beds. At Llandovery they rest upon Ordovician rocks. These rocks occur with a narrow crop in Pembrokeshire, which curves round