Death Valley’s rocks, structure and landforms offer a wealth of information about what the area may have looked like in the past. It is apparent that there has not always been a valley here. Death Valley’s oldest rocks, formed at least 1.7 billion years ago, are so severely altered that their history is almost undecipherable. Rocks dating from 500 million years ago, however, paint a clearer picture. The limestones and sandstones found in the Funeral and Panamint Mountains indicate that this area was the site of a warm, shallow sea throughout most of the Paleozoic Era (542 - 251 million years ago.)