Keywords: stereoscopic stereophotography stereophotographs historical usgs history geology mapping black and white blackandwhite bnw stereograph blackandwhite monochrome outdoor black and white Zion National Park, Utah. Virgin River, west fork in the Mukuntuweap Branch. U.S. Geographical and Geological Survey of the Rocky Mountain Region (Powell Survey). Zion National Park, Utah. Virgin River, west fork in the Mukuntuweap Branch. U.S. Geographical and Geological Survey of the Rocky Mountain Region (Powell Survey). |