BY A. B. WALKOM. 157 



tance to the north, the northern boundary being formed by the 

 Webber's Creek fault. This is shown by the fact, that the great 

 majority of the boulders in the gravels brought down by West- 

 brook Creek and its tributaries, consist of eruptive rocks (chiefly 

 porphyries, and dark-coloured, fine-grained rocks) and tuffs. On 

 the west of the Greta fault, the Upper Marine Series are found, 

 and they extend away westwards, past Singleton, until they dis- 

 appear under the Rix's Creek Coal-Measures. 



Immediately next the fault, there are shaly and sandy mud- 

 stones, with numerous erratics. These dip towards the east, and 

 belong to the Crinoidal Beds, being part of the eastern arm of the 

 Belford anticline. Some of the erratics are quartzites containing 

 fossils. To the north, these beds extend some considerable distance. 

 I followed them along the Dyrring Road, to a point about 4 miles 

 north of the village of Sedgefield. 



Faulting. — In this area, there are three very heavy faults. Two 

 of them are northward continuations of faults described by Pro- 

 fessor David in the Hunter River District,* namely, the Greta and 

 Elderslee faults, and, in each ease, the throw has increased towards 

 the northern end of the fault. The third has a roughly east-west 

 trend, and throws to the south. It has been called here the Web- 

 ber's Creek fault. The Greta fault has swung round from having 

 a S.E.-N.W. trend to almost N.-S., and here has a throw of about 

 1,500 feet to the east, bringing the Upper Coal-Measures down 

 into contact with the lower part of the Crinoidal Shales of the 

 Upper Marine Series. The Elderslee fault strikes a little to the 

 west of north, and has a throw of nearly 6,000 feet. The Carboni- 

 ferous rocks, near the fault, are conglomerates, and rhyolitic and 

 trachytic tuffs of Upper Carboniferous age, while, on the down- 

 throw side, are rocks of the Upper Coal-Measures. At this point, 

 then, all the rocks of the Lower Marine Series, Greta Coal-Mea- 

 sures, and Upper Marine Series that have been developed in the 

 district, are faulted out of sight. That both the Lower Marine 

 Series and Greta Coal-Measures were developed to some extent, 

 is indicated by their presence at Cranky Corner, with a thickness 



* Op. cit. pp. 302-304. 



