Geographically seen the Saxon-Bohemian Switzerland is no mountain range, it is a landscape formed by erosion in Cretaceous period. In fact a hundred million years ago, it had been a lake with a chalk bed. Once the water had run off, a hefty slab of sandstone in layers of up to 600 meters of size remained. Millions of years of weathering carved notches and crevices in this sandstone plateau. The River Elbe and its tributaries found their ways through the canyons, rinsing them out and leaving a broken, bizarre landscape made of friable sandstone that is very slowly disintegrating into sand again. The altitude differences of up to 450 meters characterize the highly unusual sandstone landscape. Conical Basalt Mountains bordered off by granite cliff faces complete the picture.
Further information about the national park you can find here: