A seismic cross-section along the Lock-Tuckey portion of the Polda Basin shows that bedrock is between 600 m and 900 m deep. Bedrock probably, consists of either Mt. Wedge type grits and con-glomerates or weathered crystalline basement. The basin sediments can be separated into five main layers, most of which persist along the entire section, each with a quite distinct and uniform seismic velocity. These units probably correlate with sediments of particular ages. The top two layers (100-500 m thick-")—consists of Tertiary and Jurassic gravels, sands, silts and clays with many carbonaceous horizons. These are underlain by claystones of unknown age, which correlate with the next two seismic horizons (100-250 m thick). Below the claystones is a thick layer of sediments (up to 500 m) which are unlikely to be Mt. Wedge type grits and conglomerates, and may be Mesozoic or Palaeozoic sediments not previously encountered in the Polda Basin. A potential coal horizon occurs immediately above the claystones, and since the top of the claystones is a seismic refractor,this method should be a useful exploration tool in other parts of the Polda Basin.The section lacks structural detail due to the low density of data points, but one structural feature of particular interest halfway between Lock and Tuckey is a broad depression of the horizons about 7 km across. This region could be prospective for coal in the upper part of the section. The section also indicates a possible north-south channel about 11 km east of Lock. This could be a favourable environment for accumulation of sedimentary uranium. A second seismic traverse north of Mt. Wedge was difficult to interpret because of velocity inversion and poor quality data due to surface calcrete and adverse weather conditions. A timedepth Section shows that bedrock dips shallowly westward, and at one point is probably faulted. A drillhole on the downthrown side of the fault did not intersect coal of any significance.