"Wilson Arch was named after Joe Wilson, a local pioneer who had a cabin nearby in Dry Valley. This formation is known as Entrada Sandstone. Over time superficial cracks, joints, and folds of these layers were saturated with water. Ice formed in the fissures, melted under extreme desert heat, and winds cleaned out the loose particles. A series of free-standing fins remained. Wind and water attacked these fins until, in some, cementing material gave way and chunks of rock tumbled out. Many damaged fins collapsed like the one to the right of Wilson Arch. Others, with the right degree of hardness survived despite their missing middles like Wilson Arch."