Gere 
uy 
ARTESIAN WATER IN ROCKS OTHER THAN CRETACEOUS. 415 
artesian water, not altogether in the Lower Cretaceous rocks, but 
partly, and perhaps largely, in the underlying Ipswich coal 
measures. Mr. Jack, in the interesting paper already quoted, 
speaks of unmistakable evidence of an unconformability between 
these two formations, and, in a sketch section, shows this uncon- 
formability to be so strong as to interrupt the continuity of the , 
Trias-Jura formation ; but bearing in mind the very large area 
which the Ipswich coal measures are known to occupy (with a 
more or less westerly dip), in the eastern portions of New South 
Wales and Queensland, and in view of the fact that at Leigh’s 
Creek, near Lake Eyre, in South Australia, coal bearing rocks 
have been identified by Mr. R. Etheridge, Junr., as the probable 
equivalents of the Ipswich coal measures,! I consider that there 
are good reasons for believing that these Triassic or Jurassic coal 
measures may be con¢inwous under the Lower Cretaceous basin. 
The occurrence of seams of coal in many of the artesian bores 
in both Queensland and New South Wales, is also a matter which 
appears to bear upon the probability that, in many cases, sediments 
which have been regarded as Lower Cretaceous may really belong 
to the Ipswich coal measures. So far as I am aware the Rolling 
Downs formation, in those localities where undoubted sections 
have been examined, is essentially a marine deposit, and it appears 
More probable, therefore, that the coal seams intersected in many 
of the bores, belong to the Ipswich beds, which we know to be 
coal bearing, than to the Lower Cretaceous beds. 
In the interests of geology it is to be hoped that bores will soon 
be put down with drills capable of extracting a solid core, which 
Would settle many of the vexed questions in connection with the 
geology of our western districts. 
' : rts on Coal-bearing area in neighbourhood of Leigh’s Creek, 
WHY. L, Brown, Government Geologist of S.A., Adelaide 1891. 
