Data acquired during the last two quaters of 1981 (Weste, 1981a, 1981b) have been used to reassess our original exploration strategy in the eastern Officer Basin (White, 1979). Results reported by Weste (1981a) clearly showed that CaSO4 type environments found in the Manya stratigraphic holes (Fig. 1) should preclude further trona exploration in that area. Evaporite pseudomorphs in core from Nicholson 1A (Weste, 1981b) were identified as shortite. However, we now consider these Nicholson 1A rocks to be mostly Precambrian with later brecciation and diagenetic alteration.