326 GREAT SERPENTINE BKLT OF NEW SOUTH WALES, vii., 



tine. When, however, we attempt to trace these subdivisions 

 through the Loomberah District, and to apply them to the suc- 

 cession in the Nundle District, we are met with difficulties, for 

 the new factors entering into the geology of the Loomberah 

 District add to the complexity of the problem. Firstly, there 

 is a general absence of serpentine throughout the region, so that 

 the boundary between the Eastern and Western Series is not a 

 distinct and unmistakable line of fault separating altered and 

 unaltered rocks, but merely a zone of transition, crushing, and 

 silicification. Secondly, even where the serpentine does occur, 

 the rocks immediately west of it have, in many cases, as highly 

 altered a character as those to the east. Tliirdly, there is de- 

 veloped a large amount of keratophyre, forming an intrusive 

 mass or masses, one of which apparently is just below the horizon 

 of the Nemingha limestones. The southern end of this zone of 

 keratophyre lies in the Hyde's Creek complex, and a further 

 occurrence of it extends from Silver Gully to Pipeclay Gully 

 (5, pp. 133-137). The northern end of the zone is that complex 

 near Macllveen's homestead in the south-eastern portion of Tam- 

 worth District(6, p. 572). With this keratophyre is often asso- 

 ciated a great amount of ferruginous and chalcedonic jasper 

 derived from magmatic solutions. Finally, there is to be con- 

 sidered the extremely disturbed and broken character of the 

 faulting, breaking-up the stratigraphical succession, so that it is 

 not possible to determine the extent of repetition of series that 

 is present. 



To simplify the reading of the detailed discussion of the several 

 formations, it may be well to state, at the outset, that the facts 

 appear to justify the following conclusions concerning the strati- 

 graphical relationships of the rocks in the Tamworth, Loomberah, 

 and Nundle Districts. 



L That tlie lower part of the Nundle Series does not corres- 

 pond with the Barraba Series, but to the upper part of the 

 Tamworth Series, namely, that lying between the Moore Creek 

 limestones and the Baldwin Agglomerates. 



2. That the ridge of conglomerate forming Nundle Sugarloaf 

 west of that township, corresponds to the conglomerate which 



