Pg.17 #2509 Close-up of Boulder Dam. View taken from the Arizona side, looking upstream. Jan. 24th, 1932. Pg.17 #2514 Close-up of slot at the Upstream Face of Boulder Dam. Jan. 24th, 1934 Pg.17 #2512 Downstream face of Boulder Dam, showing foundation for Central Wing of the Power House. Jan. 24th, 1934. Pg.17 #2510 Upstream face of Boulder Dam. Jan. 24th, 1934.