408 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



to almost 17 per cent, of ash, while those from the Upper have from 

 14 to 38. Great variation occurs in a single seam; anthracite at one 

 place, 4 feet 4 inches thick, has at one mine only 3.5 per cent, of 

 ash, vi^hereas in another it has 23.61. No igneous rocks were seen 

 in the neighborhood. 



New South Wales. — The Permo-Carboniferous, according to 

 David," is divisible within the Hunter River region into 



The Newcastle Series, freshwater, with coal seams 1,400 to 1,500 feet 



The Dempsey Series, freshwater, no workable coal 200 to 2,000 feet 



The Tomago Series, with coal seams 1,600 to 1,800 feet 



The Upper Marine Series, without coal 5, 000 to 6,400 feet 



The Greta Series, with coal seams 150 to 300 feet 



The Lower Marine Series, with little coal 4,800 feet 



A great gap exists between Carboniferous or "Gympic" depos- 

 its, which, most probably, belong to the Lower Carboniferous. On 

 the border of Queensland, in the Ashland coal field, the Permo- 

 Carboniferous rests in great unconformity against the Lower Car- 

 iDoniferous, which is not far from 20,000 feet thick. This vast 

 mass consists, in the lower and middle divisions, of marine beds, but 

 the upper division is mostly lava and volcanic tuffs. The gap is 

 indicated not only by the angular unconformity but also by the fact 

 that but one genus of plants is common and the contrast in fauna is 

 .almost as great. 



The Lower Marine Series has, at base, a deposit about 200 feet 

 thick, underlying a basalt sheet and containing many glaciated peb- 

 bles. The first appearance of Gangamopteris is at about 3,000 feet 

 from the base ; and at 500 feet higher is a coal seam of rather infe- 

 rior quality, 10 feet 6 inches thick, inclusive of the partings which 

 contain Gangamopteris. The Greta Series, sandstones and shale, 

 has near the base the Homeville seam, 3 to 11 feet 6 inches thick, 

 "hard, bituminous coal ; at the South Greta mine it rests on Kerosene 

 shale. At 50 feet higher, the interval being filled with sandstone, 

 conglomerate and shale, is the Greta seam, 14 to 32 feet thick, with 

 floor of shale and roof of sandstone or conglomerate. Where the 



^to' 



2 T. W. E. David, " The Geology of the Hunter River Coal Measures, New 

 South Wales," Mem. Geol. Survey of New South Wales, No. 4, 1907, pp. 

 :3i 1-327, 354. 



