The Tepius are table-like mountains found only in the Guiana highlands. These geological formations tend to be found as isolated entities rather than in mountain range fashion, which makes them the host of a unique array of endemic plant and animal species. Some of the most outstanding tepuis are Autana, Neblina (the highest one, on the Venezuelan-Brazil border), Auyantepui and Roraima. They are typically composed of Precambrian sandstone rocks, very hard to climb, that rise abruptly from the jungle, giving rise to spectacular natural scenery.