The term Albtrauf (Alp escarpment) refers to the northwest facing escarpment of the Swabian Alps, situated in Baden-Württemberg and Bavaria. It is the most distinctive stepped slope within the alpine region of the South German Scarplands, leading roughly from the southwest to the northeast. The Albtrauf has its geological extension in the northeast, in the stepped slopes of the Franconian Jura and in the southwest and west among the Jurassic-era stepped slopes of the Baaralb, Hegaualb, Randen, Klettgau, Aargau as well as the Table Jura stretches from the city of Basel to the Ajoie and the French Scarplands. In geology and geomorphology, however, the term “Trauf” merely describes the brink of the stepped slopes where various stepped surfaces meet (which is not developed in hipped steps). Geography Like the entirety of the Swabian Alps, the Albtrauf leads from the southwest to the northeast, approximately following the line of Donaueschingen–Lemberg–Balingen–Reutlingen–Kirchheim unter Teck–Gingen an der Fils–Unterkochen. On a closer look it is markedly interrupted by many deeply eroded valleys. The protruding inliers and outliers (German: Zeugenberge) support famous castles, which are visible from a great distance, such as the Hohenzollern Castle, the Hohenneuffen Castle and the Teck Castle. Major traffic routes leading from the alpine foothills to the Albtrauf are known as the Alb ascension (German: Albaufstieg), the best known of them being the Geislinger Steige. Geology The Albtrauf is made up of an upper rock layer of the Brown Jurassic and lower and middle layers of the White Jurassic. The harder layers of the Brown Jurassic act as the foundation of this bed and so form the highest, often weakly developed layer of the Alpine foothills. The Brown Jurassic differs regionally: Sandflaserschichten (Quenstedtsche Gliederung B β) in the eastern Alps, Blaukalke (B γ) in the mid Alps, oolithische Kalkmergel (B δ) in the western Alps. The lower section of the stepped slope are made up of the claystone layers of the Brown Jurassic, stretching to the Ornatenton Formation which ends this section. The equally soft Kalkmergel (W α) follows as the first layer of the White Jurassic. Hard limestone acts as a layer-former in the W β, (as reef limestone in the western Alps, and otherwise as the mural Wohlgeschichtete Kalk Formation), as well as in the W δ (reef limestone is found across the whole region, but especially in the young layers). In between these is a marl complex. Geomorphology