WATER SUPPLY IN THE INTERIOR OF NEW SOUTH WALES. 87 
adequate supply of artesian or other well water, and for this 
reason I shall endeavour to state, as shortly as possible, a few of the 
facts on which the opinions which I hold are grounded. 
From the western spurs of the dividing range we find the land 
sloping away to the west as far as the Darling River. West of the 
Darling, as far as the South Australian boundary, the country, 
except for a few low ranges, seems to be almost level, as shown 
the uncertain course which the water takes. In that part of the 
Colony there have not yet been any railway surveys made, so that 
we have no accurate records of the levels in any direction 
Bourke, on the Darling, as shown by the railway survey, is only 
349 feet above sea-level, and Dubbo, on the same line of railway, 
is 865 feet above sea-level. Dubbo is situated just near the edge 
sea-level. In , by barometer measurement, I made Walgett 
(which is situated on the Darling River, a little north of west 
plain which forms the interior of New South Wales has a very even 
slope to the south-west, along the course of the Darling River, 
of something less than 1 foot per mile. The fall along the 
course of the Darling River, following the bends, is only a few 
inches per mile; but I think, from a series of observations made 
by myself afew years ago, that the general slope of the country 
from the Queensland boundary to Bourke is about 8 inches 
per mile. Below Bourke the fall becomes _less. 
quartzite, and conglomerates of undetermined geological position. 
*Ina time-table issued 10 September, 1884, from the Railway Depart- 
ment, the height above sea-level of Nyngan is given as 637 feet, but as my 
formation is derived also from the survey of the line, and direct from the 
Railway Department, it is impossible to say which is correct. 
does not affect the argument, 
