AIM: The objectives of this survey were (1) to check the validity of the 1966 offshore aeromagnetic survey interpretation of a central trough running NW-SE through OEL 33, and (2) to extend, by additional refraction profiling, the mapping of the high-speed refractor (basement) from the onshore portion of the Eucla Basin of South Australia into the offshore Bight region of South and Western Australia, and to further supplement this profiling with selected reconnaissance reflection profiles, thus establishing some idea as to depth of section and nature of sediments, and to get some feel for the structural framework of the area plus a general configuration of the offshore basin. METHODS: Survey dates: 12 - 20/2/67. Energy source: explosives. CDP coverage: 300% and 600%. Recording mode: 26 channel digital - Western FA-50 recorder. SP interval: 656 feet; group interval: 328 feet and 164 feet. RESULTS: 6 lines (3 in WA, 3 in SA), encompassing a total of 175.89 line miles of refraction shooting (70 line miles in SA) plus 361.75 line miles of reconnaissance reflection work (164.5 line miles in SA) were carried out by Party 87 of Western Geophysical Co. of America, and processed in Houston, Texas, by Digital Consultants, Inc. Seismic data interpretation was also carried out in Houston by survey operator Tenneco Australia. Seismic data quality varied from very poor to very good, with apparent velocities found to be erratic across the entire area. An assumption of 12,500 feet/sec average velocity, a figure taken from the SADM onshore refraction work, was used throughout the survey for estimating depth to basement. Stacking velocities indicate that this figure could be considerably less, with some indications that the average velocity of sediments above the high-speed refractor might be as low as 6500 feet/sec. A comparison between the aeromagnetic and seismic data, where dual coverage exists, indicates that the magnetics are not accurately depicting depth to the high speed refractor, and so are thought not to be worthwhile including in future exploration efforts. The reconnaissance seismic work indicates the possible existence of two troughs, one with a maximum of from 5000-9000 section feet (assuming 12,500 feet/sec. average velocity) in central OEL 33, and the other with from 5000-8000 section feet in eastern PE 254H, western PE 175H, and northern PE 242H and PE 243H.