Originally noted for its late Tertiary and Pleistocene fossils of animals such as the giant sloth Megatherium and Glyptodon - an enormous type of primitive armadillo, this wild region of southern Argentina is now the source of a number of major dinosaur discoveries.
The first systematic research undertaken of the fossils of this area was conducted by the English naturalist, Charles Darwin, while on his voyages with H.M.S. Beagle.