328 
The sediments laid down in Middle Tertiary times to the north of the 
“ Primitive Mountain Chain ,n formed the foundation of the vast area 
occupied at the present day by the basins of the Wimmera, Murray, Darling, 
Murrumbidgee and Lachlan Rivers. The features of this large subterranean 
catchment area were clearly summarized by Reginald Murray in his 
Report on Artesian Well-boring in the Wimmera District, furnished to the 
Geological Survey in 1882. 2 He there pointed out that the Wimmera area 
is the natural outlet for the vast quantity of subterranean water which must 
continually flow down to the sea from the upper reaches of the Murray basin, 
since the hard foundation rocks of Palaeozoic metamorphic schists at the base 
of the Grampians on the Victorian, and similar rocks on the South Australian, 
side of the Murray forming the Mount Lofty and Mount Barker ranges, are 
the portals through which this vast underground river must flow. 
2. POSITIONS OF THE BORES. 
The bores systematically dealt with in this report are situated in the 
Mallee, to the north of that area generally known as the Wimmera district, 
and are all in the county of Weeah. (See Fig. 39.) They commence at 
about 6 miles east of the South Australian boundary near Pinaroo, and 50 
miles north of the 36th parallel. They are continued in a line due eastward 
from Kow Plains at distances of 2 to 4 miles apart. The water in these 
borings has been met with at 170-250 feet from the surface, and in most 
cases has risen to within 10-70 feet of the surface. 
The bores are numbered from 1 to 11, in regard to the samples examined. 
A further series of borings, however, has been made in the same district 
of the Mallee, but the material from these has been held over for want 
of time to devote to its examination. Moreover, a detailed inspection of the 
succeeding bores would in all probability add very little to the interesting 
results already gained, w r hich it is hoped will form an introduction to the 
scientific study of the borings in this area. 
3. METHODS OF BORING. 
The samples of rock from the various depths in the borings were taken 
at reasonably short intervals. 
The boring was effected by a Victoria percussion drill. The softer strata 
were penetrated by the ordinary twist bit or shell auger. Casing was used 
to prevent the sides of the bore falling in, but this was not put down imme¬ 
diately the depth was lowered ; sometimes there being as much as 60 feet 
uncased at a time. In this way there was obviously some risk of admixture 
of samples taking place within limits of distance corresponding with the 
uncased portion of the bore-hole. 
For the harder portion of the strata, such as limestone and indurated sand- 
rock, the chisel or star-bit was used. Since the fossils in this kind of material 
were never of large size, nor easily obtained by disintegration in water, the 
good results were not lessened by this rough means of extraction. 
Considering the methods of obtaining the material generally, the results 
were surprisingly satisfactory. For instance, large numbers of moderate¬ 
sized fossil shells, as Glycimeris, Leda, Limopsis , Venus, Meretrix, Natica , 
Turritella and Tylospira, and also fossil sea-urchins as Scutellina and Psam - 
mechinus , were obtained in perfect condition from the sandy and shelly clays ; 
and further, the smaller mollusca and minute organisms, as ostracoda and 
foraminifera, were found in great profusion on washing, sifting and sorting 
the material. 
Gregory, J. W T . Geography of Victoria, revised ed., 1912, pp. 75 and 76 
Prog. Rep. Geol. Surv. Viet., Vol. VII., 1884, pp. 96-100 
