Stromatolites afford a means of stratigraphic subdivision and correlation in Precambrian sequences which, contain few or no other fossils. Detailed field and laboratory studies are necessary in order to classify stromatolites. Determination of the time ranges of the taxa so defined in the USSR has shown that they are stratigraphically restricted, and work in Australia and elsewhere has largely substantiated these findings. Correlations based on Russian time ranges are mostly in agreement with radiometric evidence; the McArthur Group and Paradise Creek Formation are correlated with, the Lower Riphean, the Burra Group and Bangemall group with the Middle Riphean and the Bitter Springs. Formation with the Upper Riphean. The Pertatataka Formation and the Umberatana Group probably approximate to the Upper Riphean Vendian boundary. Dating of the basement of the Adelaide Geosyncline near Adelaide and a recent find in the Callanna Beds of stromatolites resembling certain Late Riphean forms present an as yet unresolved conflict with the Burra Group correlation.