Jukes on Atcstralia. 
379 
resembling beds he knew in the valley of the Hunter, to the north¬ 
ward, which had the same position with regard to the coal. They 
were about 400 feet in thickness. 
2. The thick mass of sandstone above them was called by Mr. 
Clarke provisionally “ the Sydney sandstone.” It consists of 
very thick beds of white and light yellow sandstones, in some 
places fine-grained, at others coarse, and containing small quartz 
pebbles. Lithologically it resembles the millstone-grit and the 
sandstones of the lower coal-measures of the north of England. 
Its beds are parted occasionally by thin bands of shale and con¬ 
tain no organic remains, so far as is known. Its thickness is 
fully 700 or 800 feet. 
1 . The upper shales contain a few small fragmentary vegetable 
impressions and bits of leaves, and I believe also some fossil fish. 
Their thickness must be at least 300 feet, but may be much more. 
The most conspicuous member of this series in the country around 
Sydney is No. 2, the Sydney sandstone. The districts composed 
of it are always rocky and barren, with a level or gently sloping 
outline when viewed from a distance, but when traversed are found 
to be eaten into or furrowed in every direction by innumerable 
ravines. These have almost invariably steep if not perpendicular 
sides, with projecting and overhanging ledges of rock. They are 
narrow in proportion to their length and depth, the latter often 
very great, and when the sandstone rises any height above the 
sea, becomes enormous*. The same character still continues 
however even below the sea-level, as it is this which gives their 
peculiar form to the harbours of Port Jackson and Broken Bay, 
with their many long winding narrow arms bounded by precipitous 
rocky cliff’s. 
The upper shales, as might be expected, form a country with 
very different characters, namely gently undulating plains and 
round-topped lumpish hills. This is shown in all the district 
between Parramatta and Emu Plains, Windsor and Campbelltown. 
In a good physical map, such as Sir T. Mitchell’s map of New 
* See Mr. Darwin’s description of two of the most celebrated valleys of this kind on the 
slope of the Blue Mountains (Darwin’s Journal). Mrs. Meredith also describes them in her 
account of New South Wales. 
2 b 2 
