In a search for economic Tertiary brown coal in the south-eastern Murray Basin, a large reconnaissance drilling programme was undertaken during February-April 1981 to test known carbonaceous sediments reported as encountered by previous drillholes and water wells. 83 rotary mud vertical open exploratory drillholes were put down in the Marmon Jabuk and Cooke Plains areas. Lignite was found in four holes located near Peake, and was followed up by drilling a further 4 rotary mud and 2 partially cored holes during June-August 1981. This work has indicated a potential lignite resource of 580 million tonnes, with a minimum depth to the top of the seam of 120 m. The lignite occurs in a NW-SE trending, fault-bounded half graben, and lies along trend from the Moorlands coalfield. Ultimate analyses made of drill core samples of the coal have shown that it is of lower quality than the better known South Australian lignites, although the shale oil yield resulting from carbonisation of kerogens is quite high (80-110 l/tonne). Stratigraphic evidence obtained by the drilling has suggested that there is little prospect for the occurrence of lignite at depths shallower than 120 m in this region. Assaying of selected drillhole samples for base metals and gold gave no anomalous values.