Jurassic Museum of Asturias The museum displays and collections cover 3,500 million years, and although they emphasize the three stages of the Mesozoic (Triassic, Jurassic and Cretaceous), information is also presented on the preceding and subsequent periods. Different stages of the Jurassic geologic period and system are on display. Corridors contain over 20 dinosaur replicas; measuring over in height, their weight would exceed ten tons if the replicas were real. A rich collection of footprints and fossils found in the Asturian Jurassic coastline from ten paleontological sites are exhibited in the exposition halls and are said to be "the most complete informative and representative
Cretaceous local subdivisions are still in use. As with other older geologic periods, the rock beds of the Cretaceous are well identified but the exact age of the system's base is uncertain by a few million years. No great extinction or burst of diversity separates the Cretaceous from the Jurassic. However, the top of the system is sharply defined, being placed at an iridium-rich layer found worldwide that is believed to be associated with the Chicxulub impact crater, with its boundaries circumscribing parts of the Yucatán Peninsula and into the Gulf of Mexico. This layer has been dated at 66.043 Ma.