Keywords: stereoscopic stereophotography stereophotographs historical usgs history geology mapping black and white blackandwhite bnw stereograph blackandwhite monochrome photo border outdoor serene black and white Zion National Park, Utah. Head of the Narrows, North Fork Virgin River.U.S. Geographical and Geological Survey of the Rocky Mountain Region (Powell Survey). Stereoscopic view. Zion National Park, Utah. Head of the Narrows, North Fork Virgin River.U.S. Geographical and Geological Survey of the Rocky Mountain Region (Powell Survey). Stereoscopic view. |