An unnamed fin natural arch in Mesa County, Colorado
Photo by Jay Wilbur
NABSQNO 12S-697340-4293300. This unnamed fin natural arch is eroded through a narrow dike of Pre-Cambrian igneous rock. It is located above Unaweep Canyon in Mesa County, Colorado. It can be viewed from State Highway 141. Vreeland included this arch as number 23-39 in his catalog and reported a span of about 30 feet.