Black and white image of Ray Lyman Wilbur, Secretary of the Interior, at a ceremony which inaugurated construction on the Boulder City branch of the Los Angeles and Salt Lake Railroad, signaling the beginning of the Boulder Canyon Project, later known as Hoover Dam. From left to right, the men pictured include: Senator Key Pittman of Nevada; Governor Fred Balzar of Nevada; Carl Gray, President of Union Pacific Railroad system; Secretary Wilbur holding the Nevada silver spike; and Senator Tasker L. Oddie of Nevada. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

The caption on the back of the image reads, " "Like grandfather, like father, like son" is an appropriate title for this photograph of Ray Lyman Wilbur II and Ray Lyman Wilbur III, reading the name of Ray Lyman Wilbur I on a bronze plaque at the Hoover Dam. As noted on the plaque, Ray Lyman Wilbur I was secretary of the Interior during President Hoover's administration and played a major role in administrative matters pertaining to the construction of Hoover Dam. His son and grandson, shown here, were visitors to the dam recently and were given a specially-conducted tour by the Bureau of Reclamation's guide service. The father and son reside at 1808 Indiana Street, Vallejo, California. The plaque is on the left hand side of the entrance to the Hoover Dam's Arizona elevator tower through which a third of a million visitors leave the dam and power plant each year following guided tours of this mammoth structure on the Colorado River between Nevada and Arizona. Guided tours of the dam and power plant, starting at the elevator tower on the Nevada side, are available daily to the public between the hours of 8 a.m. to 5 p.m. Ca. 1950's (Bureau of Reclamation photo)."

This photograph has three images. The first one, (0272_0014) reads, "Train load of gravel coming in three shay engines used for this load. Gravel comes from downstream of Boulder Canyon," as a handwritten inscription. The second one (0272_0015) that's upside down reads "March 9, 1934. New Union Pacific Train arrives at Boulder Dam." The third one (0272_0016) that's vertical shows the top workings on Boulder Dam from NV rim of Black Canyon (U.S. Bureau of Reclamation photo). It reads, "Top of dam about one form wide, everyone getting in each others way. '(0)' shows how much the slant of the dam has shortened the pours - form raisers have this one in place, waiting for carpenters to build the short side panels. (x) points out upstream face panels - form raisers nightmare, water soaked and patched up, very leery of climbing out, and straddling that lower 2x6 and start unbolting the panel. Notice the hand rails on other panels, but nothing to protect you from walking off the most thrilling fall of your life. Reeves often would (when we were safely out of sight, sitting astride a 2x6) he would sling out a bolt, and wait that long, long minute before it hit bottom. And say, 'Boy,' I'd hate to fall that far.' To be continued."

This photograph has three images. The first one, (0272_0035) shows people high scaling Boulder Dam. The handwritten inscription reads, "The Blackbirds drilling holes for blasting. High scalers, tough job. No chance to sleep here unless you want a long nap. 'Blackie', the graveyard shifter, tells me when he was working the drill from a bo'sn chair. He caught a man who had fallen out of his chair. Had a little too much of on the rocks. Some did fall without any help." The second image (0272_0036) shows the last big blast at Boulder Dam. (Provided by U.S. Bureau of Reclamation) It reads, "Blasting walls of canyon for keyway." The third one (0272_0037) is a picture of Coffer dam at Boulder Dam. The inscription reads, "Steel beams pile driven, rock filled and covered with reinforced concrete. Note size of trucks (at this time, largest in the world) in front of largest 'drilling jumbo' in the world also. There's six working levels on each side for men to work from, and is forty ft. long. About fifty men, each with a tender, works on this jumbo."

This photograph has three images. The first one (0272_0056) reads, "See the river behind the dam. A heavy flow storming upriver, slot in middle of dam has gauges installed along to register heat generated by this pile of cement. Pipe strung along bottom of each pour on each level of the dam, ends in the slot. Each pipe at each level will be pumped with refrigerated water until each level has been cooled. Then the pipes will be pumped full of cement. They will then fill that 5 ft. height. If not cooled, would generate enough heat to explode." The second one (0272_0057) is upside-down, and it reads, "#8 hi-line with doors open; line is slack on doors. This line is called, by bell boy to operator, the load line. When full of mud this line carries the load. No.8 is now using single line, makes it faster and quieter." The third image (0272_0058) reads "No.8 and No.7 working off hi-trussel." The top arrow: hook tender, bottom arrow: donkey operator and his donkey - run by electricity." It also says, "No.8 using 4 yd. bucket to pour small forms on the face of the dam. Some forms become quite small as the slant of the dam shortens them at each height."