This photograph has three images. The first one (0272_0023) has a handwritten inscription that reads, "Part of foundation for powerhouse" (on Boulder Dam). The second one (0272_0024) reads, "Arizona outlets for valve house on Boulder Dam. Penstocks protruding, waiting for the valve house to be built around them. (x) shows location of working tunnel to receive the pipes to put them in place. Will be plugged later." The third one (0272_0025) reads, "The Dam - indentation in canyon walls are for intake towers. Comparatively small down between the gigantic walls of Black Canyon. Still below river level, but looks like a lot of concrete to me. Train (x) on trussel, with 8 yds. bucket of mud, from lower mixing plant. Nice stroll across the catwalk ($) or better yet, try climbing that wig-wagging stairway wiggling up the canyon wall. I know a guy who did it (once)," as a handwritten inscription.