As the title of this work implies, the area included within its scope is about one-quarter of the Australian continent. It extends on the north to near the tropic of Capricorn, and on the south is bordered by the Southern and Pacific Oceans connected by Bass Strait. This tract has a great range both of climate and temperature, from the dry continuous heat of Central Australia, to the severe winter climate of the Australian Alps, and the warm moisture of the coast lands. The most striking features of this part of Australia are the Dividing Range and the vast plains of the interior, through which the rivers, which rise on the inland fall of the Dividing Range, wind their tortuous course, in two great river systems, the one to the Southern Ocean, and the other to Lake Eyre, in Central Australia, where such water as can find its way there evaporates.

The sources of the Murray, which with its great tributary the Darling flows to the Southern Ocean, rise along the Dividing Range for a distance of over a thousand miles. Those of the Thomson and Barcoo, which lower down form Cooper's Creek, extend along the Dividing Range for a further distance of three hundred miles. The rivers which rise on the other side of the Divide have short but vigorous courses to the sea.