258 THE PHYSICAL GEOGRAPHY OF AUSTRALIA. 



Victoria, and 24,387 in South Australia. The whole basin is divided into 

 two unequal areas — an effective or contributing area of 159,889 square 

 miles, with a mean annual rainfall of 25.03 inches, and a noncontribut- 

 ing area, or that which either contributes nothing to the river system or 

 which contributes only during exceptional floods, of 254,364 square 

 miles. The mean annual rainfall over the latter does not exceed 17.15 

 inches. The largest noncontributing area of 158,863 square miles lies 

 within the colony of New South Wales, comprising a tract of country 

 east of the Bogan and Darling, an extensive region bounded by the 

 Darling, Murray, Murrumbidgee, Lachlan, and Bogan, and the territory 

 west of the Darling. The whole drainage area of 24,387 square miles 

 within the territory of South Australia contributes nothing to the river 

 system ; here the mean annual rainfall is only 16.83 inches. The delta 

 lands and other noncontributing areas of 36,835 square miles in Queens- 

 land lie chiefly along the southern boundary of the colony within the 

 counties of Belmore, Carnarvon, Oassillis, and along the middle basin 

 of the Warrego Biver, the mean annual rainfall over that part of the 

 country being about 18.97 inches. The area of 34,279 square miles in 

 Victoria that contributes nothing to the river system is a strip of 

 country south of the Murray and west of Morong, where the mean 

 annual rainfall is something like 17.85 inches. Most of these non- 

 effective areas consist of immense alluvial plains and gently undula- 

 ting country where the rainfall is very small and uncertain ; the soil is 

 remarkably rich, and, if irrigated, would be highly productive. There 

 is a mean annual rainfall of 20.19 inches over the whole drainage area 

 of the Murray Biver. Considering the enormous extent of the water- 

 shed, the sectional areas of the primary river and its chief tributary 

 are insignificant. The mean average discharge of the Biver Darling 

 at Bourke is equal to about 6,557 cubic feet per second, and the approxi- 

 mate mean height of water level for a period of twelve years was 10 

 feet. The mean average discharge of the Murray Biver equals 2,791 

 cubic feet per second at Euston, 6,336 at Modina, and 3,516 at Albury. 

 The approximate mean height of water level at the same places for 

 1879-1890 was 15.6, 16.10, and 12.10 feet, respectively. At Albury the 

 discharge of the Murray very rarely falls below 1,000 cubic feet per 

 second, even in the driest seasons. 



The primary source of the Murray Biver proper is in the western 

 face of the Australian Alps at the union of two lateral spurs, by which 

 it is flanked on the east and west, about 20 or 30 miles north of Mount 

 Kosciusko, whose peak of 7,256 feet above sea level marks the culmi- 

 nating point of the great southern cordillera. It flows southerly 

 between these spurs or mountain ranges, skirting the northwestern 

 base of Kosciusko, where it sweeps toward the northwest and joins 

 the Indi Biver, whose source is within the Victorian territory. The 

 entire length of the Murray is about 1,700 miles, but there is a remark- 

 able discrepancy between writers upon this subject — it being indeed 



