Lake Eliza is a hypersaline coastal lake in southeast South Australia, a region of winter rainfall and summer drought. It is fed by ground waters and has no connection with the sea. Salinity rises from < 100 in winter to > 360%() in summer, with accompanying fall in lake level. The lake contains a biota of generally non-marine lineage. Two areas of the lake margin exposed in summer were studied. One, on the western shore, was protected from prevailing winds, the other, on the eastern shore was exposed to wave attack. The western shore is an area of fine carbonate sediments with high organic content. The eastern shore is an area of moderately sorted quartz-carbonate sand of lower organic content. The sediments of Lake Eliza are similar to some of those described from the Wilkins Peak Member of the Green River Formation, USA, and a comparison between the two systems suggests that the lamosite oil shales of the type found in the Green River Formation may not have been deposited in a fresh to brackish lake floor as has been supposed, but could have formed beneath cyanobacterial mats along a protected margin of a saline lake, in a setting equivalent to the western margin of Lake Eliza.