266 T. W. EDGE WORTH DAVID. 



basaltic base. Fragments of granites are observable entangled 

 in the mass of one of these dykes at Cambewarra. 



Coal-fields (6), (7), and (8). 



The Talbragar, ISTamoi, and Gwydir Coal-fields have as yet been 

 very little explored. It is probable that they are the equivalents, 

 of the Newcastle or of the Tomago Coal-measures. A short 

 description of portion of the Talbragar Coal-field is given by my 

 colleague Mr. W. Anderson in the "Annual Report of the Depart- 

 ment of Mines for 1888," and of portion of the Namoi Coal-field 

 by my colleague Mr. Gr. A. Stonier, in " Records Geological Survey 

 New South Wales," Vol. n., Part ii. 



Coal-field (9). 



The Ward's River Coal-field is an outlier from the main field, 

 and is from one to two miles wide, and over twenty miles long 

 occurring in the form of a long narrow trough infolded between 

 the strata of the Rhacopteris beds. It contains several seams of 

 workable coal, one of which lying near the bottom of the basin is 

 as much as thirty feet thick, and below this is another seam, 

 which, inclusive of bands, is thirty-two feet thick. The coal in 

 these seams has been converted into anthracite by the heat and 

 pressure, to which it has been subjected. The strata on either 

 side of this basin dip at an angle of 45° towards the centre of the 

 trough. The flora of this coal-field is remarkable for the pre- 

 dominance of Gangamopteris in the lower strata of the field, this 

 plant becoming much scarcer in the upper beds, where its place 

 seems to be taken by Glossopteris. It is probable that these coal 

 measures are the equivalents of either the Tomago or of the 

 Newcastle Coal-measures. 



Group III. 



Thinnfeldia and T.eniopteris Series. 



The formations belonging to this group are developed principally 

 near Sydney in the basin of the Hawkesbury River, near Dubbo, 

 and in the Clarence District. In the Sydney and Clarence Districts, 

 the group may be divided into the following three formations, the 

 newest being placed first : — 



Wianamatta Shales ... ... Upper Clarence Series. 



Hawkesbury Sandstone ... ... Middle ,, 



Narrabeen Shales (including cupri- I T 

 ferous tufts and Estheria shales ) 

 In the Dubbo district, according to the observations of the Rev. 

 J. Milne Curran, f.g.s., the group may also be divided into three 

 series as follows, in descending order : — 



Tseniopteris beds. Hawkesbury Sandstone. Ballimore beds.. 



