248 C. A. SUSSMILCH AND T. W. E. DAVID. 



PART I. 



Introduction. 



It has been the practice in the past in New South Wales 

 to include under the term Carboniferous all those strata 

 which occurred between the Devonian formation on the 

 one hand, and the Lower Marine Stage of the so-called 

 Permo-Oarboniferous formation on the other hand. There 

 is some reason for thinking that at least part of the so- 

 called Permo-Oarboniferous system of this State should be 

 included with the Carboniferous system, but the evidence 

 for and against this view will be discussed fully by Prof. 

 David in Part II, so this matter will not be further debated 

 here, and the term Carboniferous will be used with its old 

 limitations. 



The Carboniferous formation of New South Wales occurs 

 only in the north-eastern part of this State. It outcrops 

 on the coast from the Manning River to Port Stephens, 

 and extends westerly thence in a broad belt along the 

 southern margin of the New England Tableland, to the 

 151st meridian (Plate XVIII); the Carboniferous belt then 

 swings northwards round the western margin of the New 

 England Tableland to the Queensland border. In this 

 present article it is proposed to describe in some detail 

 that part of this Carboniferous belt which occurs immedi- 

 ately north of the Permo-Oarboniferous basin of the Lower 

 Hunter River District (the southern part of the County of 

 Gloucester) and particularly that part of the formation 

 which occurs in the lower parts of the valleys of the 

 Paterson and Williams Rivers (see Plate XXXI). Although 

 this district is well-settled and readily accessible, very 

 little detailed geological work has been done in it, probably 

 due to the fact that the deposits of economic value are few 

 and unimportant. The work of previous investigators in 

 other parts of the State will, however, also be drawn upon. 



