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THE COAL MEASURES OF NEW SOUTH WALES AND 

 THEIR ASSOCIATED ERUPTIVE ROCKS. 



By T. W. Edgeworth David, b.a., f.g.s. 

 Communicated by permission of the Hon. Sydney Smith, Minister 



for Mines and Agriculture. 



[Read before the Royal Society of N.S.W., December 3, 1890.^ 



Introduction. 



The Coal-measures of New South Wales may be ranged provis- 

 ionally into three groups, and if the lignites and brown coals of 

 Tertiary age are also to be included in the term Coal-measures, a 

 fourth group must be added. These four groups are as follows, 

 the oldest and lowest being placed first : — 



Group I. — Rhacopteris and Lepidodendron Series. Age Palaeozoic, 

 Carboniferous. Contains a few thin unworkable coal seams. 

 Thickness over 10,000 feet. 



Group II. — Glossopteris Series. Age Palaeozoic, Permo-Carboni- 

 ferous. All the productive coal seams at present being 

 worked in New South Wales belong to this group, which 

 contains in the aggregate a thickness of about 150 feet of 

 workable coal, in those localities where each division of this 

 series are fully developed. Thickness about 11,000 feet. 



Group III.—- Thinnfeldia and Tceniopteris Series. Age Mesozoic, 

 Triassic (?). In the Clarence District contains some seams 

 of coal, which are likely to be workable. Thickness about 

 2,500 feet. 



Group IV. — Brown Coals or Lignites. Age Tertiary, Eocene to 

 Pliocene. Greatest thickness of a single seam of brown coal 

 in New South Wales about thirty feet. Greatest thickness, 

 of strata proved up to the present about 100 feet. 



Detailed description of various Groups. 



Group I. 



(A) Sedimentary. 



The sedimentary rocks of this group have been studied by the 

 Rev. W. B. Clarke, f.r.s., Mr. C. S. Wilkinson, f.g.s., Mr. J. 

 Mackenzie, f.g.s., Mr. Odenheimer, Mr. Surveyor Herborn, Mr. 

 R. Etheridge junr., Mr. S. H. Cox, f.g.s., and many others. 

 They have been examined most in detail in the Stroud District, 

 where Mr. J. Mackenzie, on behalf of the Australian Agricultural 

 Company, cut trenches across the upturned edges of these strata, 

 which proved them to have a thickness here of at least 10,000 

 feet. The upper half of this thickness appears to be in that 



Q— December 3, 1890. 



