Nullarbor

a plain in South Australia between the Great Victoria Desert and the Great Australian Bight. It is composed of strongly karsted Paleocene limestone; as a result there is no surface drainage. Along a steep scarp to the coastal lowland there are numerous tubular springs of an artesian basin. The surface is smooth with sinks up to 1.5 km in diameter. The climate is subtropical and semidesert. The precipitation, which falls mainly in the winter, averages 200–350 mm per year. Sections of oraches and halophytes sparsely cover desert sierozem soils with solonetzes and solonchaks.