A preliminary field geological examination of an area at Mount Harvey, located about 25 miles south-east of Oodnadatta, where a deposit of siliceous ?Tertiary claystone material occurs which it was hoped might be suitable for use as an absorbent, did not disclose the presence of any other potentially economic minerals, e.g. lateritic iron ores or bauxite, and opal. An indicated resource of approximately 40 million tons of siliceous siltstone and claystone has been estimated to be present in a synclinal structure developed at Mount Harvey, based on available mapped exposures. Trenching and drilling will be required to assess the actual tonnage of mineable material occurring there. Its extraction should present no problems in a geotechnical sense.