The Alberga 4 mile Military Sheet, situated in the north-west of South Australia is bounded by latitudes 26° and 27°S and longitudes 132° and 133° 30'E. It embodies the following 1 miles sheets - Giles, Ernabella, Indulkana, Kenmore, Alcurra, Moorilyanna, Rateringinna, Marryat, Officer, Echo, DeRose, Paroora. Of these the first three have been prepared as 1 mile sheets. Field work was carried out during 1953 with the aid of serial photographs. Particular emphasis has been placed on the stratigraphy and petrology of the area. Field investigations and petrographic studies have shown that the area consists predominantly of highly granitised gneissic rocks, together with plutons of adamellite. Intruding the foregoing rocks are dykes of gabbroic composition. In the South East of the area Proterozoic glacigene rocks are recognised. Overlying these with marked angular unconformity is a flat lying series of arenaceous sediments, principally massive sandstones, which on lithological grounds suggest correlation with the Larapintine Series of Central Australia. (?) Tertiary rocks occur as scattered, flat topped residuals. The area receives a summer maximum rainfall, precipitations occurring between November and March. Rainfall, however, is deficient and unreliable, averaging about 5 to 6" on the plains but rising to 10 to 11" in and about the ranges (Ernabella 10.5"). The climate is characterised by a marked diurnal variation in temperature, typical of a continental climate. Consequently the vegetation consists of very hardy types including mulga (Acacia spp.) principally on the sand plains, eucalypts fringing creeks, native figs (Ficus platypods) and pines (Calitris sp) on granitic outcrops, spinifex (Triodia spp.) In an around the ranges and saltbush (A triplex sp) on creek flats and clay plans. Mulga and saltbush provide valuable stock fodder. Other herbaceous plants include parakylia (Calandrinia Balonnensis) and native grasses (Panicum effusum, Aristida sp etc.). H.Y.L. Brown investigated the extreme south east of the area and indicated the presence of rocks of probable Ordovician age. R. Lockhart Jack traversed most of the area under discussion. Although his map is rather generalised, it has proved to fundamentally corrent and of great value as a basis for more detailed mapping. A.F. Wilson has carried out field and petrographic studies on the rocks in the north west of the area.