ARTESIAN WATER IN N. S. WALES AND QUEENSLAND. 431 
on the assumption of course, that it did not expend itself in forcing 
the water out at the intake. 
DIscusSsION. 
Mr. F. B. Grpps—Professor David in the course of his interest- 
ing paper remarked on my difference of opinion as to the generally 
accepted theory that the origin of artesian supply is due to hydro- 
static or hydraulic pressure. My objection to such a conclusion, 
which becomes the more strengthened the more I examine artesian 
basins, is the impossibility of tracing, except in few instances, a 
direct connection or continuity of strata between the artesian 
basin and the presumed source of supply. For instance, take the 
artesian well at Grenelle near Paris, which is 2,000 feet deep. 
Water was struck at 1,798 feet, and burst up with a pressure of 
1,160 ibs. per square inch equal to a column of water 2,673 feet 
high. If this artesian supply is due to hydrostatic pressure, where 
is its source? The Vosges Mountains about two hundred miles 
distant, have a limited area above that height, but after accounting 
for frictional and capillary forces, the extra head would not be 
sufficient to account for such pressure. The Jura Mountains, 
about two hundred and thirty miles south-east, afford the only 
area of sufficient height and extent to provide it, but there is no 
evidence of a continuity of strata from the Jura to the Paris 
basins. In the case of the well at Kissingen in Bavaria, 1,878 
feet deep, where the jet rises four feet higher than at Grenelle, 
the projecting force has been distinctly proved to be due to carbonic 
acid gas generated along the junction line of gypsum with lime- 
stone. The rise of the oil in the petroleum wells of America most 
certainly cannot be attributed to hydrostatic pressure. The oil 
collects in free sand enclosed between an impervious shale or slate 
at bottom, and a shell of siliceous schist with quartz febbles at 
the top thus occupying the same position as most artesian waters. 
The average depth of these wells is from 1,600 to 1,800 feet. 
Some shallow wells are only 500 feet, whilst the deepest well is 
3,000 feet deep. The force which compels these wells to overflow 
