The LINDSAY 1 :250 000 sheet area occupies parts of the southern Musgrave Block and the northern Officer Basin, in the North West Province of South Australia. It is entirely contained by the Great Victoria Desert. The oldest rocks are gneisses of amphibolite and granulite facies, which have resulted from high grade regional metamorphism of acid igneous rocks and sedimentary rocks during the ?late Carpentarian-?early Adelaidean. These gneisses have been intruded by granites (usually allanite-bearing) and basic dyke rocks. Clastic sediments of Adelaidean age have been equated with the Burra Group and the Pound Quartzite of the Wilpena Group. Clastic sediments of late Marinoan or early Cambrian age outcrop very poorly. A sandstone of probable Cambro-Ordovician age outcrops towards the eastern side of the area, and is overlain by Palaeozoic-Mesozoic sandstones. A lacustrine limestone of Tertiary-Quaternary age is found blanketing parts of the crystalline basement and older sedimentary rocks. Other Quaternary units include a red clay sandy soil, an aeolian gypsum deposit, extensive sand dunes and sand spreads, minor amounts of alluvium and talus, and gypseous and clayey lake deposits. Most of the area is covered by sand dunes, amongst which are widely separated outcrops of rock.