Based on the latest (R 6 survey) seismic interpretation, after intergration with previous seismic survey results and newly obtained well information, Shell's Duntroon Basin permit areas can now be subdivided into 4 structural zones: (i) a monoclinal fault zone (ii) a folded zone (iii) a step-faulted zone; and (iv) a synsedimentary faulted zone. The first three zones coincide with the continental shelf area, where a water depth of 100 fathoms (600 feet) marks the shelf outer boundary, while the fourth zone underlies the upper continental slope in deeper water (to 10,000 feet). At present 5 prospective geological features are recognized within the Duntroon permit areas. Wallaroo and Bandicoot leads are located in the step-faulted zone. This zone is currently regarded as having the best exploration potential, because here the upper Cretaceous sandstone reservoirs occur at generally drillable depth, while the associated source rocks are expected to be mature enough to lie within the oil window. Jerboa lead is situated on the southern edge of the monoclinal zone, where a shallow basement high is intersected by a Cretaceous anticline of unknown stratigraphic content. Cuscus and Koala leads are located in the folded zone, and would have to rely for closure on possible dip reversals along the plunging axes of the anticlines mapped in this zone. Additionally, here only a thin section of reservoir sandstones is predicted to be preserved beneath the base Tertiary unconformity. Finally, unconfirmed but sizeable leads can be recognized in the deep, synsedimentary faulted zone, although further seismic is required to detail them for possible drilling using as yet unavailable technology.