A short review of previous work is given and the difficulty is emphasised of interpreting deeper geological structure due to extensive alluvaeolian sediments. Monoclinal meridional escarpments are evident in the Morgan area. They are attributed to basement faulting, each with downthrow to the east. The structures occupy a zone about 10 miles wide and can be traced from Sedan for about 100 miles to the north. It is termed Morgan Structure and is thought to be responsible for the deviations of the Murray from a westerly course into a southerly direction. Locally, dips approaching 20 degrees east were observed on the east side of the structure. A NW-SE. flexure is predicted at the Pyap Bend near Loxton and is correlated with the Murrayville monocline in western Victoria (downthrown to NE). Gypsum lakes and swamps mark an elongate depression in keeping with the prediction. The Marmon-Jabuk structure shows as a pronounced WNW-ESE lineament, but there is strong possibility that it is not a structure but a fossil marine coastline. A chapter is dedicated to the origin of fossil dunes by high- impact winds in the Pleistocene glacial period.