Nearctic realm represented by the Madrean Region. Although North America and South America are presently joined by the Isthmus of Panama, these continents were separated for about 180 million years, and evolved very different plant and animal lineages. When the ancient supercontinent of Pangaea split into two about 180 million years ago, North America remained joined to Eurasia as part of the supercontinent of Laurasia, while South America was part of the supercontinent of Gondwana. North America later split from Eurasia. North America has been joined by land bridges to both Asia and South America since then, which allowed an exchange of
Matterhorn plate, a small continent which broke up from Africa before the Alpine orogeny. For this reason the Matterhorn has been popularized as an African mountain. The Austroalpine nappes are mostly common in the Eastern Alps. The Swiss explorer and geologist Horace-Bénédict de Saussure, inspired by the view of the Matterhorn, anticipated the modern theories of geology: The formation of the Matterhorn (and the whole Alpine range) started with the break-up of the Pangaea continent 200 million years ago into Laurasia (containing Europe) and Gondwana (containing Africa). While the rocks constituting the nearby Monte Rosa remained in Laurasia, the rocks constituting