348 
PROCEEDINGS OF SECTION C. 
The gold from the higher portions of this old drift has been 
redistributed during later times, and has been worked in shallow 
deposits in numbers of the small gullies heading from the Mount 
Browne Range. 
At Tibooburra the auriferous Cretaceous drifts dip off an area of 
granite rocks. Another instance of gold being found in Cretaceous 
rocks was seen at a place called the Peak, between Morden and 
Tarella stations, on the Milparinka-Wilcannia road. The Peak itself 
is an isolated conical hill of Upper Silurian slates capped (uncon- 
formably) with Upper Cretaceous quartz and ironstone conglomerate. 
In the adjoining hills to the north of the Peak the conglomerate dips 
to the north-east under a considerable thickness of Upper Cretaceous 
sandstone. The tenant of the Peak (xovermnent Tank (Peter Riley) 
has obtained a fair amount of alluvial gold by following the ironstone 
conglomerate to the dip, and also by working the recent gullies which 
intersect it, and in which the gold has been reconcentrated. 
Large areas of this north-western country, particularly to the 
south-east of Milparinka, are covered by what are known as sandhills 
and claypans. The sandhills are formed by the action of the wind in 
heaping up the sand derived from the Upper Cretaceous sandstones. 
The occurrence of the claypans which alternate with the sandhills is 
peculiar. They consist of depressions in the surface from a few 
inches to perhaps 3 feet in depth, and varying in diameter from about 
50 feet upwards. Each claypan has a flooring of impermeable clay. 
Many of these claypans are almost perfectly circular, while others 
have the form of long channels of regular width. It seems probable 
that they owe their origin to the whirlwinds (the “ Burramugga” of 
the blackfellows) which are of such common occurrence in this 
country. Many of the whirlwinds remain stationary for a considerable 
time, which would account for the formation of the circular depres- 
sions, while others travel for considerable distances, and may thus 
scoop out the long channels just alluded to. The depressions having 
once been formed, subsequent rains carry into them water having in 
suspension a very small amount of finely divided clay derived from the 
surrounding soil*. When the water is afterwards evaporated by the 
sun’s heat, a fine coating of clay is left on the floor of the depression; 
and frequent repetitions of this process leave a thick fioor of clay, 
forming a hard and impervious bed for the water. 
9.— ON THE PRESENT STATE OF OUR KNOWLEDGE OF THE 
OLDER TERTIARIES OF SOUTHERN AUSTRALIA. 
By G. B. PRITCHARD , Lecturer in Geology , Working Men's College , Melbourne . 
In this paper I wish to give a sketch of the various opinions 
which have been held by various writers on the Tertiary geology of the 
southern parts of Australia, and the evidence, as far as can be 
gathered, for the expression of those opinions. 
By the term “ Older Tertiary” it is usually understood in the 
European area that beds of Eocene age only are indicated ; but in 
Australia, on account of the comparatively poor development of the 
marine Pliocene beds, and the great development and geographical 
