An unnamed lava natural arch in Cibola County, New Mexico
Photo by Jay Wilbur
NABSQNO 12S-764900-3870570. This unnamed lava natural arch is one of a series of arches that formed due to selective roof collapse of a large lava tube through basalt. This tube and its arches are located in El Malpais National Monument, New Mexico. Access is via a marked, but very rough, hiking trail from a parking area maintained by the Monument. Vreeland included this arch in his catalog as number 17-108. It has a span of about 30 feet.