546 GREAT SERPENTIXK-BRLT OF NEW SOUTH WALES, V., 



probably much nearer to the true stratigraphical succession, 

 though even here are faults, the extent of which cannot yet be 

 determined, which render all estimates of relative thickness of 

 strata very unreliable. The absence of many good horizons, and 

 the lateral variation of some of the formations are additional 

 causes for uncertainty. On this account, we can no longer 

 accept, as final criteria, the distinctions previously made between 

 the cherts of the Tamworth Series and the mudstones of the 

 Barraba Series, or between the p^^roclastic rocks of the Barraba 

 and Tamworth Series and the Baldwin Agglomerates. In spite of 

 this, however, the general facies of a series of associated rocks is 

 usually conclusive. It has been found necessary to separate 

 the limestones of Moore Creek and Tamworth from those in the 

 Moonbi (Nemingha) district, the stratigraphical evidence con- 

 firming Mr. Etheridge's conclusion, drawn from palseontological 

 evidence, that the latter were on a lower horizon. There is 

 reason to believe in the occurrence of a third limestone-horizon, 

 the relation of which to the limestone of Moore Creek is not yet 

 obvious. The three limestone-horizons have been termed the 

 Nemingha, Moore Creek, and Loomberah horizons respectively. 

 The last-named is as yet but little known, and its description is 

 reserved until the study of the Parish of Loomberah is made. 

 The several divisions of the formations developed will now be 

 discussed' in chronological order. 



1. The Eastern Series, partly of Lower Devoniaii age. 



It has been assumed in previous papers, that the rocks east of 

 the serpentine, comprising jaspers, and phyllites, are largely 

 of Lower Devonian age, and, to the Lower Devonian rocks proper, 

 the name Woolomin Series has been applied. Unfortunately, 

 they are so intensely folded and faulted, and have thrust in 

 among them so much that seems to be derived from the Middle 

 or even Upper Devonian Series^ that it has not seemed worth 

 while, at present, to attempt to disentangle the Woolomin Series 

 from the others, if such a series should really exist. The 

 whole complex, therefore, will be considered together under 

 the term Eastern Series. The following discussion refers only 



