162 GEOLOGY AND PETROGRAPHY OF CLARENCETOWN-PATEESON DISTRICT^ i., 



later, in collaboration witli Messrs. Dun and Browne, discussed in greater detail 

 the geology of the Carboniferous rocks of the Currabubula District (Benson, 

 Dun and Browne, 1920). 



A. B. Walkom, in addition to some work at Pokolbin (Browne and WaUvom, 

 1911), made observations on the stratigTaphj' of the Carboniferous Series in the 

 Glendon Brook district (Walkom, 1913), and has recently discussed the age of 

 the Carboniferous rocks of the Hunter Valley, on the evidence of their fossil 

 flora (Sussmileh and David, 1919, Appendix 1). 



Besides some work on the stratigTaphy of certain areas (Browne and Wal- 

 kom, 1911), W. R. Browne has studied the petrolog-y of the Carboniferous Series, 

 particularly the rocks of the upper terrestrial division (Sussmileh and David, 

 1919, Appendix II., and Benson, Dun and Browne, 1920, Section C), but many 

 of the results of the research have not yet been published. 



The most important step in the development of our knowledge of Carboni- 

 ferous geological histoi-y took place as a result of the investigations by Mr. 

 Sussmileh and Professor David of the Carboniferous Series in the F'aterson- 

 Dungog region, which followed on the discovery, in 1914, by the latter geologist, 

 of the occurrence of tillite at Seaham. These authors (Sussmileh and David, 

 1919) proposed the name "Kuttung Series" for the terrestrial strata which, in 

 New South Wales follow the Lower Carboniferous Burindi Series, and which 

 they regarded as representing the Middle Carboniferous and Upper Carboni- 

 ferous (in part). 



The outcome of the work done in the past decade is that the Paterson- 

 Clarencetown district must now be looked upon as the type-area for the Kut- 

 tung Series, as it is from evidence collected in parts of this region that Sussmileh 

 has established the general sequence of that Series. 



In view of the geological importance of the Kuttung Series, especially on 

 account of the developujent of volcanic rocks in great variety, together with a 

 wonderful series of glacial beds, the suggestion was made by Professor Sir 

 Edgeworth David, and supported by Messrs. Sussmileh and Browne, that the 

 writer should begin an investigation of the type area, paying particular attention 

 to the petrographic aspect of the work. 



Accordingly, five weeks of 1920 and three months of 1921 were spent in 

 field work. During these periods a detailed geological and topographical survey 

 Avas made of an area bounded by a line running from Wallarobba past Hilldale 

 south-west to Vacy, south to Mt. Johnstone and Paterson, east-south-east to 

 Seaham, across to the Limeburner's Road about six miles from Clarencetown, 

 and west along that road through Clarencetown back to Wallarobba, a region of 

 about 200 Sq. miles. Observations in adjacent districts, chieHy to the north, were 

 also made in order to render more simple the interpretation of certain features 

 in the limited area. 



It is proposed in the present paper to describe the detailed stratigraphical 

 succession and regional geologj', leaving matters connected with tectonic geology, 

 physiography and petrolog-y for later communication. 



The General S^eqiience of the Carboniferous Bocks in the Lower Hunter District. 



The broad succession, as determined by Mr. Sussmileh, is as follows: 

 I. Burindi Series. — ^The chief units comprise limestones, sometimes oolitic and 

 often impure, tuffs of acid and intermediate composition, conglomerates and mas- 

 sive lava-flows. There is some indication that the limestones occur low down in 

 the series and that the lavas may be near the top. A minimum thickness of 5000 

 feet is suggested. 



