XV 
IV —Summary and Conclusions. 
( 1 ) The Foraminifera described in this Monograph occur chiefly on two 
horizons, separated from one another by a thickness of about 4,000 
feet of strata. The Upper Horizon (Wollong Horizon; is in the 
Upper Marine Series, and the Lower Horizon (Pokolbin Horizon) is 
in the Lower Marine Series of the Permo-Carboniferous System of 
N. S. Wales. 
The great thickness of the marine beds separating the two 
horizons, and the fact that the Greta Coal Measures are also interposed 
between them, as well as the differential facies of the associated 
fossils, proves the age of the Woflong Horizon to be distinctly newer 
than that of Pokolbin. 
(2) The nature of the sediments associated with the Foraminifera, as well 
as the paloeo- geography of the surrounding country, shows that the 
Foraminifera of both Wollong and Pokolbin lived in shallow seas 
close to the old shore-lines of the Carboniferous land. 
(3) Volcanic eruptions, producing basalts and submarine basic tuffs 
partly preceded and partly perhaps accompanied the growth of the 
Pokolbin argillaceous limestone. 
(4) Glacial erratics are met with on a horizon not much below that of 
the Pokolbin limestone, while they are actually present in the 
Wollong Horizon; thus it may be concluded that the shallow seas, 
in which the Foraminifera flourished, had their waters occasionally 
chilled by floating ice. At the same time, the fact must be borne 
in mind that at Wollong an abundance of the Coral Trachypora 
Wilkinsoni is associated with the Foraminifera, from which it may be 
inferred that the temperature of those seas was after all not very low. 
(5) The further study of the Foraminifera of the Upper and Lower 
Marine Series of N. S. Wales may supply valuable data for 
correlating members of the Permo-Carboniferous System of Austral- 
asia even in widely-separated areas. The Piper Liver Foraminiferal 
Horizon of Tasmania is probably homotaxial with that of Pokolbin, 
as rendered probable by the great abundance of Nubecularia in 
both series, and both may, perhaps, he approximately homotaxial 
with that of the Irwin River Limestone in West Australia. 
If this conclusion is correct, the principal Palaeozoic Foraminiferal 
Horizon of Australia is situated, as far as is at present known, in the Lower 
Marine Series. At the same time, it is quite possible that the Irwin River 
Horizon may be of the Carboniferous age, and so be considerably older than 
the Permo-Carboniferous horizons of Wollong, Pokolbin, and the Piper River. 
