Despite the palaeoecological emphasis of most recent stromatolite research outside the USSR, controversy still exists regarding the environmental restriction of these organosedimentary structures and in some cases, analogies with modern occurrences have been maintained too rigidly. Palaeo-environments should be determined where possible by a combination of all biological and sedimentological evidence. In South Australia, Cambrian and- Precambrian carbonate rocks which form a substantial proportion of the thick sequence in; the Adelaide Geosyncline, contain widespread stromatolites, which have been studied according to methods developed in the USSR and classified into the form taxa "group" and "form". The absence of independent biological environmental indicators in the Precambrian section necessitates a reliance on general stratigraphic and sedimentological data for the interpretation of regional palaeogeography and local environmental conditions. The Skillogalee Dolomite, older than the lower of two Late Precambrian tillites, contains one predominant form of stromatolite almost throughout its extent, although-at least one additional, form occurs locally. These stromatolites chiefly grew as biostromes in littoral and lagoonal settings on' an extensive, level, carbonate-depositing platform, probably of restricted access to the open sea. The interspace and associated sediments show evidence of varying energy conditions, degree of oxidation and possibly salinity, but the same stromatolite persists, although there is some modication of morphology, such as the presence of micro-unconformities in the higherenergy environments. The Umberatana Group, stratigraphically the interval including the two tillites, has basinal shales and siltstones,in its lower part, but during a subsequent widespread regression, the marginal parts of the basin were shallowed sufficiently to allow the growth of stromatolites, probably in water depths ranging from shallow subtidal to low supratidal. In addition, in the northern central part of the basin, offshore banks of shallow water limestones may have been related to areas of diapiric activity. The stromatolites of the Umberatana Group most often occur as bioherms of varying sizes intimately associated with ooid and intraclast grainstones, crossbedded sandy limestones, and, in marginal areas, penecontemporaneous dolomites. Twelve forms of stromatolites have been distinguished in the Umberatana Group. Different forms may occur in sequences of seemingly indistinguishable lithofacies. These observations from the Adelaide Geosyncline strengthen the view that stromatolite morphology is at least partly biologically controlled, the defined taxa being largely independent of the local environment.