Red River Gorge
View of the north end of Sky Bridge in the Red River Gorge Geological Area. Note the joint (fracture) in the bedrock of the left side of arch in this view. Rock fins develop by erosion between parallel fractures (joints) in the massive sandstone of Corbin Sandstone Member. An arch forms gradually, over time, by weathering and erosion processes collectively called exfoliation. Rock shelters (large overhangs, or "shallow caves") gradually expand with time until two of them merge through opposite sides of a narrow ridge (fin) to form a natural arch.
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Last modified: 10/22/2010