The Arrowie is a sedimentary basin composed nearly entirely of unmetamorphosed Cambro-Ordovician detrital and carbonate strata. It covers a present-day area across the Flinders Ranges, westwards to Lake Torrens and eastwards to the New South Wales border; Wopfner (1972) suggested that it may have had ancient depositional connections to the Warbuton and Stansbury Basins and the Bancannia Trough. For many years traces of hydrocarbones have been reported from Cambrian outcops in the Flinders Ranges (Mawson, 1939; McKirdy, 1971). The Department of Mines drilled two wells, Mudguard 1 and Yalkalpo 2, into the eastern Arrowie Basin during 1975 and 1976. Prior to this, the only other wells which had been drilled to test the hydrocarbon potential of this area were Lake Frome 1, 2 and 3 (Delhi, 1968), 80km southwest of Mudguard 1 and Yalkalpo 2. They were drilled as stratigraphic tests and results confirmed that the basin had potential for hydrocarbon production (Delhi, 1968). Mudguard 1 and Yalkalpo 2 were designed to test the lithology and hydrocarbon potential of the Cambrian strata in a relatively unexplored area. This note summarises the most important results of this drilling programme; full details are presented in the well completion reports (Youngs, 1977). All cores, cuttings and electric logs are freely available for inspection at the Department of Mines.