166 GEOLOGY AND PETROGRAPHY OF CLARENCETOWN-PATEESON DISTEICT;, i., 



undoubtedly near the base of the Kuttung Series, supports the opinion ex- 

 pressed by Sussmilch that the lava-fiows in the Burindi Series occur towards 

 the toj) of that Series. 



The Passage of the Burindi Series into the Kuttung Series. — The relation of 

 the Burindi Series to the Kuttung Series in the area under discussion is one of 

 conformity, as announced by C. A. Sussmilch, but the actual line of demarcation 

 between the marine and freshwater beds is hard to determine. In many places 

 where one would hope to find definite evidence as to the nature of the transition, 

 heavy and complex faulting causes confusion. 



Along the road leading from Hilldale up the Wallarobba Ridge, there are 

 in the road cuttings, exposures of tuffs of Burindi age. In them there are small 

 bands of conglomerate, ' gxeatly subordinate to the tuffs until just near what 

 appears to be the top of the Burindi Series. However, just at the top of the 

 ridge the base of the Basal Stage of the Kuttung Series is encountered, but the 

 occurrence of the tuft's similar to the underlying Burindi tuff, interstratifled 

 with these basal conglomerates, and the existence of conglomerate towards the 

 top of the marine series, makes it difficult to place the dividing line. 



At Clarencetown, on the outskirts of the town in the cuttings on the Dungog 

 road, and in the water-tables of the Maitland road, there occurs, just below the 

 conglomerates of the Basal Stage of the Kuttung Series, a fine-gTained cherty 

 mudstone or shale in which, it is stated, plant remains have been found. This 

 horizon is unlike any of the Kuttung strata and has been regarded in the present 

 work as belonging to the Burindi Series. It was considered as the topmost bed 

 of the marine series during the mapping, and conglomerates and tuffs occurring 

 beneath it must be referred to the marine Carboniferous. Further along the 

 strike of this unit one comes upon similar but more compact rocks (e.g., on the 

 Glen William Road) carrying a varied marine Burindi fauna, and as experi- 

 ence has shown that many of the minor horizons of both the Burindi and Kut- 

 tung Series do not persist for any great distance along the sti-ike, one . feels 

 confident in regarding the unit mentioned above as being the top of the Burindi 

 • Series. 



KuTTUxG Series. 



As a result of the careful consideration of the stratigraphical details ex- 

 hibited in the region under investigation, the writer suggests the following sub- 

 division of the Kuttung Series in the type area, viz. the Paterson-Clarencetowu 

 district, such classification being substantially the same as that proposed by C. 

 A. Sussmilch, with suggested modifications resulting from the writer's more re- 

 cent work. 



(i.) Basal Stage. 



All the strata from the base of the conglomerates which, following on the 

 Burindi Series, occur at Wallarobba and elsewhere, to the base of the hornblende- 

 andesite and andesite-glass (Martin's Creek type). This stage corresponds with 

 Sussmilch's Wallarobba Beds. 



(ii.) Volcanic Stage. 



The strata from the base of the hornblende-andesite to the base of the tuffs 

 and conglomerates formerly known in the Faterson Valley as the Mt. Johnstone 

 Beds. 



The rocks of this stage form a distinctive set of lavas and tuffs with sub- 

 sidiary conglomerates. Whilst igneous material occurs throughout the Kuttung 

 Series (and tuffs of primary deposition are just as important units as the mas- 



