Discusses previous work (particularly of Jack in Geol Surv. of S.Aust. Bulletins, 11 and 14). Geology: Stratigraphy; the dome is capped by a few tens of feet of Tertiary. The Patchawarra Bore penetrated about 4,000 feet of Winton Formation and was still in Tambo at TD (5,458). No bores within 98 miles of dome have penetrated the full Cretaceous section. Winton beds are grey shales with thin sands and coal. Tambo beds are dark grey siltstones and shales with thin fossiliferous limestones. Pre-Cretaceous stratigraphy in the area is unknown, but thick porous sands occur elsewhere. Structure: The simple structure of the Great Artesian Basin is modified by gentle folding in its central zone. The Innamincka Dome is one of the more southern of these folds. Its axis is 50 miles long, and the structure is 20 miles wide with limb dips averaging 2 - 5 degrees; surface closure is of order of several hundred feet, possibly greater at depths. Gas shows (mainly methane) from drilling of water wells are common in the area. Reservoir beds are abundant in the Jurassic or Triassic sequences near the E edge of the basin.