Referenced by Selection: Geological and Geographical Atlas, Colorado, 1877 Your Browser doesn't support iframes. Geographic Area Covered: Colorado, New Mexico, North America--Rio Grande Valley, United States--San Luis Valley, Rocky Mountains Geographic Coordinates: (W 107°00ʹ--W 104°30ʹ/N 38°00ʹ--N 36°45ʹ) View on Google Maps