44 T. W. E. DAVID. 
Department of Mines in 1878 on the Bowenfels and Hartley 
district. Downwards this Upper Devonian, or Lower Carboni- 
ferous formation, is probably separated, by a strong unconformity, 
from the Upper Silurian formation, typically developed at the 
Jenolan Caves and at the Lime-kilns near Bathurst. It is at 
the former locality that radiolarian jaspers have recently been 
discovered by me, not far from a well-marked limestone horizon 
of Upper Silurian Age containing an abundant marine fauna. 
Evidence for this unconformity has been quoted by Mr. J. Clunies- 
Ross,! and further evidence has been collected by Mr. W. F. 
Smeeth, some of my geological students and myself, in the neigh- 
bourhood of the Jenolan Caves as shown on diagram 1, Plate 2 of 
this address. 
6. Permo-Carboniferous system. All the rocks of this system 
are separated from those of the preceding by a very strongly 
marked unconformity, gently inclined strata of Permo-Carboni- 
ferous being observable in many places, e.g., near Capertee and 
Rydal, reposing on vertical strata of the Upper Devonian series. 
Included pebbles of Upper Devonian quartzites, containing 
Spirifera disjwncta, as well as of the granites which have intruded 
the Devonian rocks, are conspicuous in the basal conglomerates of 
the Permo-Carboniferous system. The unconformity is still 
further emphasized by an extensive over-lap of the Upper Marine 
series, which conceals from view both the Greta Coal-measures 
and the Lower Marine Series throughout the entire area of Permo- 
Carboniferous rocks exposed on the western escarpment of the 
Blue Mountains, as shewn on my section of this district already 
published.* 
The six divisions of the Permo-Carboniferous system recog- 
nizable in the type-district of Maitland are in ascending order :— 
1. Lower Marine Series. 
2. Greta Coal-measures. 
3. Upper Marine Series. 
1 Quart. Journ. Geol. Soc., Vol. u., 1894, pp. 108 - 109 and p. 119. 
2 Annual Report, Department of Mines, 1890, p. 254. 
