408 
with the datum of sea-level, but showing variations amounting only to 13 feet 
in 20 miles. This upper water-table or hydraulic surface is at the summit of 
the Kalimnan strata (Lower Pliocene). The water seems to be almost in¬ 
variably salt or braclrish. What appears to have taken place is, that a 
limited amount of water percolated through the superficial beds until stopped 
by the impervious blue clays of the Kalimnan. Since there is no direct 
outlet to the sea for this upper water-bearing series, the salts are either 
concentrated in the water, or escape to the surface by capillarity and the 
action of the sun’s rays, forming the various salt-pans and lakes; in the case 
of the calcium carbonate this forms the travertin of the Mallee. 
(b) The full supply of fresh water was met with in each bore either at the 
top of the Janjukian or polyzoal rock series (Miocene beds), or very close to 
its upper limits. The impervious basement beds of this series may be either 
a Palaeozoic rock or a band of chert of the Cainozoic series ; or, in some cases, 
the carbonaceous clays of the lower part of the Janjukian. 
Fig. 42. Diagrammatic section showing the Janjukian (water-bearing) beds from 
Goroke to Yatpool. Bearing of line from Maryvale to Yatpool about N. 10° E. 
Approx. Scale.—Horizontal, 48 miles to 1 in.; vertical, 630 ft. to 1 in. 
(c) Going eastward this underground supply of fresh water is met with 
at the lower depths, in consequence of the thickening of the Cainozoic beds in 
this direction, due to a deepening of the basin. 
