British Isles have an interesting geological history, and therefore their division among the main mountain systems is also intriguing. Most of the archipelago was formed during the oldest Caledonian orogeny (along with Scandinavia or Svalbard), but the mountains of England and southern Ireland were formed only during the younger Hercynian orogeny. All the mountain ranges were gradually leveled by erosion, but 60-55 million years ago, after the separation of Laurentia (Greenland) from Europe, the originally Caledonian territory was uplifted again and subsequently shaped by glacial erosion. The highest mountain of the Caledonian part of the British Isles is the Scottish Ben Nevis (1344 m).