Pronounced relation between magnetic intensity and Bouguer anomaly values. In Iron Knob - Wilkatana area, near Nilpena and near Parachilna, get steep magnetic gradients and generally high Bouguer anomaly values. Between Wilkatana and Brachina get low Bouguer anomaly values with low magnetic gradient. This pattern is thought to represent the broad features of the geosynclinal basin (deepens gradually from north to south and shallows rapidly west in the Wilkatana area). Local gravity anomalies are supposedly produced by structures within the Adelaide System. Three gravity highs which may be of petroleum interest. They are 6 miles west of Parachilna; almost at Brachina; and 12 miles east of the south end of Lake Torrens. Recommends more detailed gravity work. 2 plans. SAN 59 Vertical magnetic intensity, 4 mile scale, 100 gamma contours. SAN 71 Bouguer anomaly plan, 9 mile approx. scale 10 mGal contours. See also SAN 93 in Envelope 115.