An unnamed irregular natural arch in Big Bend National Park, Texas
Photo by John Burns
NABSQNO 13R-659985-3246755. This small unnamed irregular natural arch with multiple openings has eroded through an oddly sculpted monolith of volcanic tuff known as Thunderhead Rock. It is located about a half-mile west of a parking area along Croton Springs Road in Big Bend National Park, Brewster County, Texas.