The native tribes with which we are dealing occupy an area in the centre of the Australian continent which, roughly speaking, is not less than 700 miles in length from north to south, and stretches out east and west of the transcontinental telegraph line, covering an unknown extent of country in either direction. The nature of the country varies much in different parts of this large area; at Lake Eyre, in the south, it is actually below sea-level. As we travel northwards for between 300 and 400 miles, the land gradually rises until it reaches an elevation of 2,000 feet; and to this southern part of the country the name of the Lower Steppes may appropriately be given. Northwards from this lies an elevated plateau forming the Higher Steppes, the southern limit of which is roughly outlined by the James and Macdonnell ranges, which run across from east to west for a distance of 400 miles.

The rivers which rise in the Higher Steppes find their way to the south, passing through deep gaps in the mountain ranges and then meandering slowly across the Lower Steppes until they dwindle away and are lost amongst the southern sandy flats, or perhaps reach the great depressed area centreing in the salt bed of Lake Eyre.

Away to the south and west of this steppe land lies a vast area of true desert region, crossed by no river courses, but with mile after mile of monotonous sand-hills covered with porcupine grass, or with long stretches of country where thick belts of almost impenetrable mulga scrub stretch across.