1. A gently sloping, elongated physiographic surface that connects the elevations of a mountain range with the plains nestled within a sedimentary basin. 2. Part of a thrust or normal fault surface that forms the inclined sections of the fault where it cuts obliquely across the contacts of the formations. 3. Access between two workings or levels of a mine. 4. An area with no significant bathymetric changes between the coastline and the deepest parts of a sedimentary basin.