Favoured by its proximity to two great waterways and by its two ports, Nisaea on the Saronic and Pegae on the Corinthian Gulf, Megara took a prominent part in the commercial expansion of Greece from the 8th century onwards, and for two hundred years enjoyed prosperity out of proportion to the slight resources of its narrow territory.
Round the Australian Bight it continues parallel to the coast, until south of Spencer Gulf (the basal ledge still averaging 8000 ft.
M., occupies a position a little to the east of a meridional line bisecting the continent, and south of the 22nd degree, but portions of it stretch upwards to the low-lying country south of the Gulf of Carpentaria.
Farther to the west, Van Diemen's Gulf, though much smaller, forms a better-protected bay, having Melville Island between it and the ocean; while beyond this, Queen's Channel and Cambridge Gulf form inlets about 14° 50' S.
On the north-west of the continent the coast-line is much broken, the chief indentations being Admiralty Gulf, Collier Bay and King Sound, on the shores of Tasman Land.