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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 9, 



The coal- shales of the Hunter River district are full of fossil 

 leaves, and some of them consist of a mixture of coal and clay, and 

 contam such an amount of hituminous matter that Mr. Beaumont 

 (Mineralogist to the Australian Agricultural Company) has expressed 

 an opinion that gas might be manufactured from them. Two seams 

 of coal only are being worked in this district ; a third is known to 

 exist, but is supposed to be too thin to pay for working at present. 

 It is two feet thick where seen, and is situated considerably below 

 the sea-level. The other two seams are from four to six feet thick, 

 but contain seams of carbonaceous shale which deteriorate the quality 

 of the coal. 



At the entrance of Newcastle Harbour is a perpendicular rock 

 (called Nobby' s Island), once separated from the main land, but 

 now united by a breakwater that has been thrown across for the 

 protection of the harbour. The island exhibits a good section of 

 the rocks of the coal-field. The accompanying section shows the 

 arrangement of the strata. 



Section of Nobby^s Island, Newcastle Harbour, 



1. Mould. 



2. Trap-conglomerate. 



3. Shales with plant-remains. 



4. Coal. 



5. Earthy sandstones and shales. 



6. Chert. 



7. Imperfect sandstones and shales. 



8. Coal. 



9. Trap-dyke. 



The island is intersected by a trap-dyke, 9 feet thick, running in 

 a direction nearly S.E. and N.W., and completely decomposed from 

 the top down to the sea-level, presenting only a greenish-white 

 greasy clay ; but beneath the water the dyke is perfectly sound and 

 hard ; about low-water-level it crops up through the beach, and may 

 be seen at some little distance running out into the sea. A bed of 

 coal (the second in the series), that formerly extended far beyond the 

 present limits of the island, and through which the dyke passes, has 

 been washed away by the waves, with the exception of a few feet on 

 each side of the dyke, looking like a great half-consumed log ; this 



