Siesmosaurs

Seismosaurus means "Earthquake Lizard" was a huge sauropod, up to 170 feet (52 m) long. It may be the longest dinosaur. It lived during the late Jurassic, about 156 million-145 million years ago. It had a long neck, whip-like tail, and gizzard stones to aid digestion in its stomach. Fossils have been found in New Mexico, USA.