John K. Hillers 1875 A Beaver dam [Boulder Creek] [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. 149]
Stereoview Library of Congress, Prints and Photographs Division Reproduction Number: LC-DIG-stereo-1s00895 (digital file from original photo, front) LC-DIG-stereo-2s00895 (digital file from original photo, back)
