Wheras the southeastern limits of the sandstone of the Blytheadale Group are concealed by more recent sediments, a study of hydrological data available, suggests a structural control of the limits of movement of the richly carbonate pressure water. Strong north-south lineaments, mound springs and chemical analyses provide good evidence of the boundary of the artesian basin proper and its pressure water. Good quality waters are available in a limited zone of alluvium and talus on the Eastern Flinders Ranges, and stock waters of increasing salinity extend as far as the lake. Stock waters are available from intake from the Barrier Ranges to the east. Limited intake occurs into sediments to the south especially along major creek channels such as the Siccus River. Shallow bedrock limits the movements of underground water over a wide area of the embayment.