Pg.90 #3417 View of Arizona side of lower portals clean-up. Aug. 26, 1935. Pg.90 #3397 Nevada construction adits, Valve House and plug adit portal. Note absence of upstream end of lower portal road tunnel. Aug. 21, 1935. Pg.90 #3412 View of Nevada side of lower portals clean-up. Aug. 26, 1935. Pg.90 #3431 View taken from downstream Nevada Plug adit, looking toward No.2 downstream plug. Aug. 27, 1935.

p.3 #888 Lower portals of Diversion tunnels No.3 and 4 during flood. Feb. 10, 1932 p.3 #896 Bucyrus Erie 43-B gas-air shovel was the only piece of equipment caught by the flood. Feb. 10, 1932. p.3 #884 Looking across river at lower portal of Diversion Tunnel No.3. Feb 10, 1932 p.3 #897 Looking across river from Arizona side at upper portals of diversion tunnels No.1 and 2. Truck bridge in foreground has been partially washed out. Feb. 10, 1932.

p.10 #1016 Gantry crane used in pouring concrete in invert section of upper Diversion Tunnel No.3. Mar. 18, 1932. p.10 #1019 View showing method of pouring concrete in invert section of tunnel lining. Mar. 18, 1932. p.10 #1018 view of invert forms in upper Diversion Tunnel No.3 showing method of pouring slabs. Trimming jumbo for aligning gauge of tunnels in background. Mar. 18, 1932. p.10 #1020 First 40 foot slab of concrete poured in lining diversion tunnels. Mar. 18, 1932.

p.12 #1055 Low level concrete mixing plant. View taken from cliffs on Arizona side of river. Mar. 28, 1932. p.12 #1113 Night view, looking upstream from below lower portals of diversion tunnels. Canyon presents a spectacular sight at night with myriads of lights. Apr. 8, 1932. p.12 #1058 Telephoto picture, similar to No.1055, to the left. Mar. 28, 1932. p.12 #1101 With the approach of annual spring rise in the river, the temporary truck bridge shown on right has been abandoned. Apr. 12, 1932.

p.23 #1725 Close-up of upper portal of Diversion Tunnels No. 3 & 4, during preparations for blast. Nov. 13, 1932. p.23 #1728 Close-up of upper portals of Diversion Tunnels No. 3 and 4, showing flow in diversion tunnel No.4, shortly after blast. Nov. 13, 1932. p.23 #1733 Dumping materials at temporary pile bridge to complete diversion of Colorado River. Nov. 13, 1932. p.23 #1737 Upper portals of Diversion Tunnels No. 3 & 4, and temporary dyke, after diversion of Colorado River was completed. Nov. 26, 1932.

Pg.57 #2963 No.5 Intake Tower finished to Elevation 1232, showing curtain wall. Dec. 5th, 1934. Pg.57 #3009 Telephoto looking downstream into the Arizona Spillway, showing construction of the spillway bridge. Jan. 8th, 1935. Pg.57 #2980 Looking upstream at the upper end of No.1 plug, showing forms for the Intake Transition. Dec. 19th, 1934. Pg.57 #2977 Looking upstream into No.1 plug, showing the placing of the high pressure valves and method of pouring. Dec. 19th, 1934.

Pg.96 #3549 Looking south toward Boulder Dam Switchyard, showing construction and excavation. Nov. 26, 1935. Pg.96 #3531 Looking upstream in lower No.3 Plug. Note one of pipe sections in place. Nov. 25, 1935. Pg.96 #3551 Looking upstream along Nevada approach to Boulder Dam. Note rubble wall being built and excavation for tower footings. Nov. 26, 1935. Pg.96 #3534 Looking upstream in lower No.2 plug, showing pipe in place. Nov 25, 1935.