This is a worldwide list of important and/or well-known localities where fossils have been found. Such locations may either be a geological formation or a single site. Geological formations consist of rock that was deposited throughout a specific period of time. They usually extend for large areas, and sometimes there are different important sites in which the same formation is exposed. In such cases, the sites should be listed under the appropriate formation. On the other hand, many formations are for all practical purposes only studied at a single site, usually the type locality.