7 
In the course of this work I benefited from discussions with Prof, dir Edgeworth David, 
Mr. E. C. Andrews, the Chief Government Geologist of New South Wales, and members of his 
staff, who assisted also in supplying maps and literature. With regard to the field work, 1 am 
especially indebted to Mr. H. C. Millard, Geologist for the Hunter River Oil Company, who has 
been engaged in field work in the Hunter River area for. 1 believe, over two years. Mr. Millard 
accompanied me for the greater part of the time that I spent in field work in this area, and as a 
patient and careful observer he had collected much information which he placed fully at my 
disposal. The consequent saving of time and trouble can only be appreciated by a field geologist. 
THE PERMO-CARBONIFEROUS STRATA <>F THE SYDNEY BASIN. 
1. General Description of Strata. 
The strata of the Permo-Carboniferous system of New South Wales have been classified 
in descending order as follows 
1. Upper or Newcastle Coal Measures. . 
2. Dempsey Stage 
3. Middle or Tomago Coal Measures . . 
Fresh -water deposits ; shales, sandstones, 
conglomerates ; 120 feet of coal in seams 
varying from 3 feet to 27 feet in thickness. 
JO. 
Maximum thickness, 1,600 feet. 
Fresh- water strata, devoid of workable coal 
seams ; mostly shales with some sandstone. 
Thickness varies from 200 to 2.000 feet. 
Fresh-water deposits ; similar to the Upper 
Coal Measures, with 30 feet of coal in seams 
from 3 feet to 10 feet thick. 
Thickness varies from 500 to 1,800 feet. 
4. Upper Marine Series— 
Crinoidal Shales 
Muree Rock 
Branxton Beds 
5. Lower or Greta Coal Measures 
Cherts and cherty shales of tuffaceous origin 
overlying clay shales. 
Thickness, 2,500 feet to 3,000 feet. 
Sandstones with a strong persistent con- 
glomerate at base. 
Thickness, 400 feet. -<■ 
Mudstones containing fairly large erratics, 
with conglomerate or sandstone at base. 
Thickness, 2,400 feet to 3,000 feet. 
Maximum total thickness of series, 6,400 feet. 
Fresh- water deposits ; sandstones, clay 
shales, conglomerates, and ironstones, with 
coal seams totalling from 15 feet to 43 feet 
in thickness. 
Thickness from 100 to 300 feet. 
6. Lower Marine Series — 
Farley Stage 
Loch invar Stage 
Chiefly sandstones ; massive and persistent 
Ravensfield sandstone at base. 
Thickness, 1,000 feet. 
Chiefly mudstones and shales containing 
much volcanic ash, tuffaceous sandstones, 
and occasional sheets of lava ; well-marked 
glacial horizon at base. 
Maximum total thickness. 4,800 feet. 
Total thickness of Permo-Carboniferous strata about 17,000 feet. 
Fossil remains of marine organisms of very diverse types are very abundant on certain 
horizons both in the Upper and Lower Marine Series. 
2. General Consideration of the Strata with regard to Oil. 
Now, the upper part of this sequence, the Upper and Middle Coal Measures, and the 
intervening Dempsey Beds have been extensively prospected by the drilling of test bores for coal, 
and opened up by the sinking of shafts and the development of workings along the seams during 
the greater part of the past century without the recorded discovery of any trace of oil. Oas has 
been met with, but not in greater quantities than is usual in such circumstances, and of the type 
which one expects to find associated with coal measures and not in connexion with accumulations 
of oil. The same can be said of the Lower or Greta Measures. Numerous collieries are working 
in the Greta seams around Maitland, Cessnock, Greta, and Branxton, and no oil is reported 
either from bores, shafts, or workings. 
