This category is also used for aprons (geological), blowholes, blowouts, boulder fields, cones (geological), crevasses, fissures, furrows, geological features, grades (physiographic), hammocks, inclines, landslides, meander necks, pitches (physiographic), polders, potholes, rockfalls, sinkholes, sinks, siphon (physiographic), slides (natural), slopes, talus slopes, terraces (physiographic), and uplands