No sedimentary phosphorate has been found in commercial quantities in outcropping Cambrian rocks of the Flinders Ranges. Two types of minor occurrences were defined: - 1.Those in ferruginous glauconitic limestone (consisting of pelletal apatite). 2.Those consisting of many varieties of cellophane and apatite (pellets, crystals, matrix, breccia fragments, etc.) in ferruginous impure sandstone in calcareous sequences, and generally lenticular. High iron content, or associated with ferruginous beds is ubiquitous, and detrimental for use in preparation of phosphatic fertilizers in conventional sulphuric acid treatment. Further exploration in outcropping Cambrian rocks in the Narina-Wirrealpa synclines, and at Sliding Rock and north of Leigh Creek is suggested. Subsurface exploration on the eastern Lake Torrens plain, in the Lake Frome region and in the Lake Torrens Sunklands should be carried out in association with oil and water drilling. The Parachilna Formation is expected to contain sporadic small phosphate deposits of type 2. The known Middle Cambrian rocks are unlikely to contain phosphorate in commercial quantities. Methodology is explained, and a study of geochemical methods of search is recommended.