Studies of the structure of the vertical sound field for sound propagating in the deep ocean and for long ranges are briefly summarized. Sources were towed at several depths. Source powers of the order of 25 to 35 W in the cw mode and 5 W in the band-limited noise mode were used. Results include the sound field as seen by a 32-element linear array suspended vertically at 2000 ft and used with a cw source, and as seen by one or two elements at depths between 500 and 3000 ft used with a correlator and a band- limited noise source. A limited comparison of the performance of the array as compared to the correlator is given as well as a discussion of the limitations of the two systems.