Unaysaurus unaysaurid. "Unaysaurus" lived between about 225 to 200 million years ago, in the Carnian or Norian age of the late Triassic period. It was found in the south of Brazil, which at the time was connected to northwest Africa. The whole world was united into the great supercontinent of Pangaea, which was just starting to divide into Laurasia in the north, and Gondwana in the south. A U-Pb (Uranium decay) dating found that the Caturrita Formation dated around 225.42 million years ago, putting it less than 10 million years younger than the Santa Maria and Ischigualasto Formations, from where the
Pangaea be removed, leaving geologists with the portion of this motion that shows continental drift and can be used to help reconstruct earlier continental positions. The continuity of mountain chains provides further evidence for Pangaea. One example of this is the Appalachian Mountains chain, which extends from the southeastern United States to the Caledonides of Ireland, Britain, Greenland, and Scandinavia. There were three major phases in the break-up of Pangaea. The first phase began in the Early-Middle Jurassic (about 175 Ma), when Pangaea began to rift from the Tethys Ocean in the east to the Pacific in the west. The rifting