Duntroon 1 was drilled to test the petroleum potential of the Cenomanian Platypus Formation sandstone reservoir within a large tilted Late Cretaceous horst block, the Numbat prospect. A secondary target was the underlying Barremian to Aptian Madura Formation. The Platypus succession consisted of an interbedded carbonaceous sandstone and siltstone section in the upper part, then a massive grey quartzose sandstone section with minor coal, siltstone and mudstone intervals towards the base. The Madura interval comprised an interbedded carbonaceous siltstone and sandstone section with minor mudstone interbeds. Frequent coal occurred towards the base. No significant shows were recorded and all sandstones were water-saturated. The coal showed a cut fluorescence and associated minor gas peaks. One 18.5 metre core was cut in the Platypus Formation, and 90 sidewall cores were attempted in the Madura, Platypus, Wigunda, Potoroo and Pidinga Formations, of which 81 were recovered.