SANDSTONE BELOW THE COAL A85 
These sub-carboniferous beds are well developed in Illawarra, 
where they extend with some interruptions from Wollongong south- 
ward to Shoalhaven, (see map,) through which region they were 
examined by the writer. From Shoalhaven these rocks extend inward 
along the Shoalhaven River; but to what extent we cannot say. To 
the north of Port Jackson, strata nearly identical in age outcrop at 
Harper’s Hill, and others, perhaps somewhat older, farther west at 
Glendon, and again at Mount Wingan, one hundred and twenty miles 
up the Hunter. This wide range will undoubtedly be found more ex- 
tensive when the country is farther examined, and other intermediate 
points may be made out, wherever the Sydney sandstone does not 
overlie and conceal them. 
Characters and Structure of the Beds. 
Lithological Characters and Stratification —The layers, where | 
have had an opportunity of examining them, are heht grayish-blue, 
grayish-red, and red sandstones. They are generally very argilla- 
ceous, and are properly called argillaceous sandstones. 
At Harper’s Hill the rock is a bluish or greenish compact sandstone, 
not at all schistose, containing an occasional pebble of greenstone, 
amygdaloid, or granite. Much of it is composed of fine earthy grains, 
as if from the decomposition of greenstone; there is rarely the glisten- 
ing lustre derived from grains of quartz. Some portions of the rock 
contain carbonate of lime sparingly disseminated; but this is mostly 
confined to the layers in which the fossils are most abundant. The 
fossils themselves are calcareous instead of siliceous. 
The rock at Wollongong is very similar in appearance to that of 
Harper’s Hill, and like it encloses occasionally rounded masses of 
amyedaloidal, syenitic, and porphyritic greenstone, some of which are 
very large, amounting to ten or fifteen cubic feet. In general the 
texture is fine-grained, and the colour light grayish-blue. ‘The layers 
are thick and compact, and rarely exhibit any planes of deposition, 
They vary a little in hardness, and in some parts of the Wollongong 
Point, softer layers alternate with others which are harder and more 
siliceous, the silex having been infiltrated in solution. South of Wol- 
longong, from Kiama to Black Head, the rock, where it appears in 
view, has either the same characters as at Wollongong, or is a red 
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