An unnamed cave natural arch in Mesa County, Colorado
Photo by Jay Wilbur
NABSQNO 12S-686225-4334600. This unnamed cave natural arch has eroded through Entrada sandstone. It is located above Rattlesnake Canyon in a BLM wilderness area west of Grand Junction in Mesa County, Colorado. Access requires a permit and directions from the BLM ranger station in Grand Junction. Vreeland included this arch in his catalog as number 18-18 and reported a span of about 20 feet.