Organ Pipe Cactus National Monument is situated in the Basin and Range Province along the US-Mexico Frontier. Mountain ranges here include: Bates Mountain, the Puerto Blanco Mountains, and the Ajo Range. To the south, La Abra Plain and Sonoyta Valley crop up. Summertime temperatures frequently top 100 degrees F. Fall, winter and spring are better suited for investigating the geology, flora and fauna of the Park.
Online resource:
Bezy and others (2000) Guide to the Geology of Organ Pipe Cactus National Monument and Pinacate Biosphere Reserve (66 pg with maps and illustrations). http://repository.azgs.az.gov/uri_gin/azgs/dlio/1685
