|This unit is located in western Victoria, clearly bounded by the Little Desert to the north and the Low Plateaux (Dundas Tableland) to the south. The South Australian border is the artificial western boundary and the Wimmera River Valley (Lowan Salt Valley) and the Douglas Depression comprise the eastern boundary. |
This unit is dominated by a series of parallel and sub-parallel ridges orientated NNW/SSE, interspersed with similarly aligned valleys or swales. This pattern is still discernible in the siliceous dunefield units (5.2) to the north. This landform pattern is not as distinct in this unit compared with north of the Little Desert, with the relative relief of the ridges ranging from 10 m. The ridges have an amplitude of 2km and slopes up to 5%.
The intervening valley floors may extend to plains in the west (Apsley) and nearer the eastern boundary. These valley floors are dominated by lagoonal deposits, which can be quite shallow as well as the many lakes, swamps and depressions.
The ridges consist Parilla Sand (Tpp), ferruginised at the surface which are exposed on the larger ridges, while Lowan Sand Formation (Ql), siliceous sandy material covers most of the smaller ridges and adjoining slopes; a result of reworking of the Parilla Sand. The valley floors have younger lagoonal deposits(Qrs) consisting of expansive (cracking) dark organic clays, which may be quite shallow at their edges as well as some texture contrast soils on alluvial rather than aeolian deposits.