Fins are formed when a narrow butte or plateau develops many vertical, parallel cracks.
Fins are considered an intermediary stage of many other erosional geologic features like windows, arches, and hoodoos.
Iron oxide and calcium carbonate cemented sandstones produce fins.
Lack of soil cover in these dry regions gives joints maximum control over drainage systems resulting in angular patterns, striking topography, and steep slopes.
[2] Fins commonly occur in arid to semi-arid regions, like south western United States.