I. Introduction. This contribution serves to record three different types of limestone occurring in the south-eastern region of South Australia, now actually in process of formation, at least partly under the influence of plant-growth. Except for several small isolated inliers of ancient granitic and schistose rocks, and one localized outburst of Pleistocene basic volcanic activity, the south-eastern corner of South Australia between the Murray River, the Victorian border, and the sea is occupied by calcareous, almost horizontally-bedded rocks of later Tertiary age, overlaid irregularly by Pleistocene and recent formations. The whole area is flat, and but little elevated above the sea from which it has been reclaimed since the Middle Pliocene. The more southerly portion, and especially a wide coastal belt, has become dry land in Pleistocene and some of it even in Recent times. The low coast-line of sand-hills or soft honeycombed limestone extending from the Victorian border westwards to the mouth of the River Murray owes its trend and condition largely to the prevalence throughout the greater part of the year of strong southwesterly gales blowing inland from off the Southern Ocean. The activity of the wind has developed shore-line dunes, trending roughly in a north-west to south-east direction. Under this influence there exists inland from the coast for a distance of 30 to 50 miles, or even more, a parallel series of sandy dune-ridges separated by flat or depressed areas; the latter are from several to 10 or more miles in width. An excellent example of land