Timothy H. O'Sullivan, 1871-1874 (survey), 1872 (expedition), 13. Marble Canon, one of the gorges of the Colorado, here 1,200 feet deep. The steep cliff is gray limestone and the slope below a brilliant red sandstone., [Wheeler Survey, Explorations and Surveys West of the 100th Meridian], Stereocard, detail, Etherton Gallery, LL/24733
Timothy H. O'Sullivan 1871-1874 (survey), 1872 (expedition) 13. Marble Canon, one of the gorges of the Colorado, here 1,200 feet deep. The steep cliff is gray limestone and the slope below a brilliant red sandstone. [Wheeler Survey, Explorations and Surveys West of the 100th Meridian]
