THE PHYSICAL GEOGRAPHY OF AUSTRALIA. 263 



peculiar physical structure of the country, there are uo rivers of impor- 

 tance iu the western part of the continent. True there are some of the 

 streams of from 300 to even 500 miles in length, such as the Fitzroy, 

 Ashburton, Gascoyne, and Blackwood rivers — the first three flowing 

 into the Indian Ocean and the last into Flinders Bay. But these are 

 only developed into true continental streams during periods of very 

 heavy rains, when enormous volumes of water rush through their chan- 

 nels to the sea, sometimes overflowing the banks and flooding extensive 

 areas of low-lying country. In dry seasons they are greatly diminished 

 in size, the main channels being quite shallow and of little value as 

 commercial highways. The Fitzroy drains an extensive tract of coun- 

 try, comprising considerable large areas of very fertile land. The Ord 

 Biver is a large stream ; its source is in the ravines of the Albert 

 Edward Bange, near the western edge of the Great Antrim Plateau 

 and Denison Plains, in the neighborhood of Kimberley; thence it flows 

 almost due north to the shores of Cambridge Gulf, a short distance west 

 of the mouth of the Victoria Biver. The country in the neighborhood 

 of the head waters of the Ord is very rugged and exceedingly difficult 

 to travel. None of the rivers are navigable except the Swan for about 

 20 miles. 



The whole coast line along the entire periphery of the Australian 

 Bight is the most remarkable region with which we have to deal in this 

 description of the river systems of the continent. There are no promi- 

 nent or conspicuous physical features along this part of the coast line, 

 and the geographer may look in vain for anything approaching a well- 

 defined stream of water. jSTor is this at all singular when we glance at 

 a general map of the country and see the enormous extent of level 

 plains and desert areas by which it is chiefly characterized. Except a 

 long narrow belt of sandstone cliffs with which the coast line is dis- 

 tinguished there are no prominent features to relieve the eternal 

 monotony of this dry and uninhabited region. The rainfall here is very 

 light, uncertain, and capricious, and falling on an intensely hot and 

 loose sandy surface it evaporates with remarkable rapidity before soak- 

 ing any great depth into the soil. For this reason there is an almost 

 entire absence of surface water, and consequently nothing to form or 

 maintain running streams. 



Most of the so-called rivers of South Australia are torrents in winter, 

 but mere creeks or successions of water holes in summer. In the set- 

 tled portions of the province many of them take a westerly course to 

 St. Vincent and Spencer gulfs, and a few by a southerly course empty 

 themselves into Encounter Bay, and have their sources in ranges trend- 

 ing in a northerly direction. In the northern portion, Lake Eyre, an 

 enormous basin below sea level, receives the surplus water brought 

 down from the east by the Cooper or Barcoo ; from the northeast by the 

 Warburton and Diamentina; from the northwest and west by the 

 Macuniba and Neales, respectively, and from the south by the Frome. 



