Query: What types of large fossils are found in Desert National Park?
Context: The Desert National Park in Jaisalmer is spread over an area of 3,162 square kilometres (1,221 sq mi), is an excellent example of the ecosystem of the Thar Desert and its diverse fauna. Seashells and massive fossilised tree trunks in this park record the geological history of the desert. The region is a haven for migratory and resident birds of the desert.