418 T. W. E. DAVID. 
Cretaceous porous beds occupying the areas intermediate between 
the positions of the former estuaries of the Cretaceous Rivers. 
If the same formula, which Mr. Henderson has suggested as 
being possibly applicable to the artesian beds of Queensland be 
adopted for estimating the area of the intake beds of the New 
South Wales Cretaceous Formation, the figures would be about 
350 miles x } = 44 square miles in round numbers, with an 
average rainfall of about one-quarter less than that for the Queens- 
land outcrops, viz., about twenty-two inches. This would equal | 
an outflow of about 38,000,000 gallons per day for one year. Now 
the present estimated capacity of outflow of all the artesian wells 
of New South Wales, as I am informed by Mr. Boultbee, the 
Officer-in-Charge of the Water Conservation Branch of the 
Department of Mines and Agriculture, is about 41,000,000 
gallons daily, so that according to this estimate the outflow should 
already have more than counterbalanced the supply, and the 
sinking of any further flowing wells would be at the expense 
of existing wells and would tend to lower the hydraulic grade. 
Tf however, allowance be made for the water which probably 
drains into the Cretaceous outcrop through the ancient valley 
gravels the estimates are capable of being considerably altered. 
For example, from Bathurst to Narromine there is a length of 
about 130 miles of ancient valley gravels of Post-Tertiary Age, 
and covering Tertiary, and perhaps even Cretaceous gravels for 
the last thirty miles. These gravels would average probably at 
least half a mile in width, having a total area therefore of about 
sixty-five square miles, and the water draining into them would 
be derived not only from the annual rainfall of about twenty-two 
inches on their surface, but also from the rain falling upon an 
area at least twenty times as great, even after allowing for the 
rain which is lost by evaporation and discharged by the river and 
its tributaries. 
Instead therefore of adding an area of sixty-five square miles 
with an average rainfall of twenty-two inches to the area of intake 
of the porous beds of the Rolling Downs Formation in New South 
