368 TRANSACTIONS OF SECTION C. 
particularly influenced by the character of the soil. In the better parts of the 
Mallee, with stiff clayey soil, they are with difficulty describable. In the more 
sandy and medium agricultural soils they had a marked parallelism and were 
of moderate size, but in the sand-hill and heath country (locally known as 
desert) this parallelism was of a general character only, and the sand-hills or 
ridges were known as ‘jumble.’ Some of these hills were as much as two 
hundred feet in height above the surrounding surface. None could be described 
as ‘dune morte,’ neither was it at all evident that they were fixed or fossil dunes, 
the more likely theory being that they were still being formed by action of 
single sand-grain movements. Owing to the weather being a succession of 
cyclones there was no prevailing direction of wind, though the westerly course 
of these depressions might be taken as generally governing the main sweep of 
the winds. Taking this as a general direction the ridges run with it and not 
at right angles. 
The east winds seldom occur, but frequently are of great force; they never 
shift any sand. All other winds, particularly the north-west, west, and south- 
west winds, shift sand, but only in places where man has removed the natural 
protection of herbage either by clearing or cultivation or by fires occurring in 
times of drought. None of the sand shifted is air-borne, but is rolled along the 
surface of the ground. At Wirrengren Plain, the termination of the outlet 
ereek or the final flow of the Wimmera River, there were in the drought of 
1902 after a bush-fire had swept over the sand-hills on the west some 500,000,000 
cubic yards of sand, or at the rate of 50,000,000 per mile in length drifted on 
to the plains. In the succeeding year, one of good rainfall, the herbage again 
fixed the sand-hills, while the sand on the plain gradually drifted eastwards 
until four years ago the plain was again in its original condition. Similarly 
the outlet creck itself in its course of fifty miles through white sand-hills 
retained its original section; the sand blown in at certain exceptional seasons 
gradually drifting out to the east. 
Supplementing Professor Gregory’s remarks on the phosphoric acid contents 
of Victorian soil, it should be pointed out that the Mallee soil contained only 
about twenty parts per 100,000 or one-half of the average Victorian soil. This 
refers to the agricultural part of the Mallee, whereas in the sand-hill and heath 
country the amount of phosphoric acid was hardly ascertainable by chemical 
methods, and it was practically non-existent. 
The methods of farming which led to the successful occupation of all this 
country originated in South Australia over forty years ago, where the recently 
christened ‘dry farming’ had resulted in the prosperous and productive settle- 
ment of land with under 10 inches annual rainfall. .The cost of production of 
wheat was under 1s. 6d. per bushel, and there were at least a hundred million 
acres suitable for its cultivation. 
Dr. W. F. Hume: The characters of an arid Jand cannot be separated from 
its past history, and in Egypt five physiographic features of first importance 
have to be considered. ‘These are :— 
1. A belt of deep depressions in the extreme west, the famous Oases. 
2. The broad waterless expanse of the Western or Libyan Desert, to the 
west of the Nile, and the corresponding limestone plateau region (the Maaza 
Limestone Plateau) to the east of the river. 
3. The Nile Valley with its Delta. : 
4. The Wilderness of the Red Sea Hills and Sinai with its rugged mountains 
and tortuous valleys. 
5. The Red Sea and its narrow prolongations, the Gulfs of Suez and Akaba, 
together with the coastal plains. 
Each of these divisions requires separate treatment. The paper gives a rapid 
sketch of the geological history of Egypt as known to us at present, the formation 
of the ancient core of Pre-Cambrian or Paleozoic sediments, volcanic rocks with 
invasion by granitic magmas, the brief Carboniferous marine advance, and later 
the much more important Jurassic-Cretaceous transgression, which practically 
affected almost the whole of Egypt, giving rise to the Nubian Sandstone and 
the important phosphate-bearing Cretaceous series. The Eocene strata which 
form the major portion of Central Egypt are probably formed, at the base, of 
