34 
Sedimen tary Formations 
So far, then, the question about the age of some of the Austra¬ 
lian coal must be considered as settled; and if, as in Ilkiwarra, 
the coal beds overlie the marine beds, as they do also iu the 
Eingal district of Tasmania, it would appear that all these separate 
occurrences belong to one thick series, in which marine beds and 
fresh-water beds interpolate each other. But, assuredly, in that 
case, the arrangement adopted must express the order as follows:— 
1. Upper coal measures. 
2. Upper marine beds. 
3. Lower coal measures. 
4. Lower marine beds. 
So far as I know, the latter rest frequently on a conglomerate, 
which in Tasmania I found to contain undoubted Carboniferous 
fossils. 
Since the Exhibition of 1SG2, on which occasion, in a paper on 
the Coal Fields, J noticed the occurrence of oil-bearing cannel 
coal at the foot of Mount York, and at Colley Creek in the 
Liverpool Ranges (not on eastern waters), the former has been 
in great request for the purpose of producing illuminating oils ; 
and the produce has been brought into the market. In the 
former locality, and in Burragorang, 1 have made some researches 
which have satisfied me that these can only belong to the upper 
coal measures. At Burragorang the blocks of cannel are found 
in an intermediate position, between the top of the coal measures 
and the upper marine beds, which (if the overlying measures 
themselves do not) certainly bear the very strongest resemblance 
to a part of the Hunter Liver series. 
In Iliawarra, also, there are shales Which are above that 
geological position, and which produce oil for illumination, but 
are not of the peculiar character of the cannel at Mount York, 
which in a great degree, resembles the Bog Head mineral of 
Scotland, only it is more valuable. The character of this 
substance is such as to justify its being considered a species of 
Bathvillite or Torbanite, in consequence of its colour and woody 
condition. 
It has unquestionably resulted from the local deposition of 
some resinous wood, and passes generally into ordinary coal, 
many portions of the same bed exhibiting the unmistakable 
features of the latter and the impress of fronds of Glossopteris 
as plainly as they are shown on ordinary coal shale. This 
hydrocarbon varies somewhat in composition ; and (as at Colley 
Creek) is frequently filled with quartzose part icles, showing that 
it was deposited in a shallow pool, to which sand was drifted 
perhaps by the wind. 
At Reedy Creek, now called Petrolia, there is a band of thin 
and very elastic substance of this kind, separated from the 
thicker bed below by a parting of white clay. 
