Drilling jumbos (aka Williams Jumbo) mounted on the back of a truck for starting construction of lower portal No. 4, Arizona side of Black Canyon. 9-26-31. (This first wood-frame jumbo was experimental - the jumbos later were steel pipe)

Looking up Black Canyon from a point below all the lower portals, showing the Government pumping plant (lower left), the Six Companies' compressor plant (middle left), the location of the lower portals, & the highway loop above the canyon wall (upper center) - 7/30/31.

p.16 #1074 Scaling down canyon wall, in excavation for intake tower on Nevada side. Apr. 1, 1932. p.16 #1073 Close-up of No.1074 to the left. Workmen are 700 feet above river. Apr. 1, 1932.

Pg.23 #2534 Boulder Dam, looking upstream. Cooling Tower in foreground. Feb. 15th, 1934. Pg.23 #2560 General view of Boulder Dam, looking upstream. March 1st, 1934.

Pg.44 #2776 Close-up of No. 3 Arizona Intake Tower, showing the cylinder gates being placed. July 24th, 1934. Pg.44 #2775 Close-up of the Arizona Intake Towers, from the High Catwalk. July 24th, 1934.

Pg.84 #3358 Looking upstream toward Boulder Dam and the Power House. July 25, 1935. Pg.84 #3362 Looking toward the Power House and Valve Houses, from top of Boulder Dam. Jul. 25, 1935.

Pg.1 #2262 Hoover Dam. June 27, 1933. Pg.1 #2256 Cut-off trench at upstream side of Hoover Dam. June 23rd, 1933. Pg.1 #2263 Hoover Dam. June 27th, 1933.