The slate mountains of the Vogtland and Thuringian Highland stretch from the Thuringian Forest to the Ore Mountains (Erzgebirge). They are between about 300 m to NN high, and comprise gently rolling hills which are part of the backbone of the Central Uplands. They extend for about 75 km from east to west and 50 km from north to south. Typical features of the landscape are the dolerite peaks or Kuppen (like the Pöhlde or the Hübel) with their wooded crests. These are made from a volcanic rock, dolerite, which is harder than the surrounding rocks and so weathers more slowly, giving rise to the characteristic Kuppen.