John K. Hillers 1873 Pa-ru-nu-wips, Heart of Singing Water Canon [U.S. topographical and geological survey of the valley of the Colorado River of the west, by J.W. Powell and A.H. Thompson. No. 023]
Stereoview Library of Congress, Prints and Photographs Division Reproduction Number: LC-DIG-stereo-1s00783 (digital file from original photo, front) LC-DIG-stereo-2s00783 (digital file from original photo, back)
