The main feature of the relief of the Mont Ventoux massif is a significant north-south asymmetry. Of lithological origin, it was accentuated by tectonics and maintained by erosion and the evolution of the faults both on the edge and inside the massif. The summit of Mont Ventoux is located in the center of the 15.5 mi (25 km) long, narrow, and asymmetrical ridge oriented east-west that forms the major morphological feature around which the massif is organized. The main escarpment is oriented north and dominates the Toulourenc valley from 4,921 ft (1,500 m). It is marked by very steep upper slopes cut by ravines with active scree and surmounted by the Urgonian limestones of the summit part. The southern slope, cut by coombs and valleys, has a more sunken eastern part and a western part with a curved and regular structure.