Geology of the Alps (300 Ma), the Hercynian or Variscan orogeny, in which the supercontinent Pangaea formed from Gondwana and Laurasia, was ended. East of the terranes that now form the Alps was the Paleo-Tethys Ocean. The effects of wind and water were able to chemically and mechanically erode and destroy the Hercynic mountain ranges. In the Permian, the main deposits in Europe were sandstone and conglomerate, products of erosion in the Hercynic mountain range. At the same time, crustal extension took place because the mountain range was isostatically unstable (this is called orogenic collapse). Due to extension, basins formed along the axis of
Pangaea closing the Paleo-Tethys Ocean, but forming a new ocean, the Tethys Ocean, in its southern end. Most of the landmasses were all in one. By the Triassic Period, Pangaea rotated a little and the Cimmerian plate was still travelling across the shrinking Paleo-Tethys, until the Middle Jurassic. The Paleo-Tethys had closed from west to east, creating the Cimmerian Orogeny. Pangaea, which looked like a "C", with the new Tethys Ocean inside the "C", had rifted by the Middle Jurassic, and its deformation is explained below. Fossil evidence for Pangaea includes the presence of similar and identical species on continents that