194 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.W. 



These are silurian in type. There can be no question that 

 the fossiliferous limestones are interbedclecl with the phyllites 

 and slates ; so the whole formation may be unhesitatingly 

 accepted as silurian in age. There is still additional evi- 

 dence pointing in the same direction. Resting unconformably 

 on the slates are to be found in places a series of sandstones 

 and grits containing the well known brachiopods Spirifer 

 disjunctus and Rhynchonella pleurodon. These Devonian rocks 

 are in turn overlaid by carboniferous beds. These succes- 

 sions can be studied well by examining the country to the 

 east of the Bathurst-Limekilns Road, on the upper reaches of 

 the Winburndale, and generally, from the spurs of the Winburn- 

 dale Mountains, in the same neighbourhood, across to the Lime- 

 kilns. To sum up, we have evidence from the fossils enumerated, 

 as well as stratigraphical and lithological proofs, of the position 

 of the slate formations in the geological series. 



When one approaches Bathurst, from any side, it will be noticed 

 that as the granite region is approached the slates show signs of 

 disturbance. They become more fissile in character, and faults are 

 frequently developed. Contorted strata, principally slate, are to be 

 seen in every creek or favourable cutting. Good examples of this 

 occur about Peel, and an exceptionally good contorted section is 

 exposed in a road cutting on the right of George's Plains and Cow 

 Flat Road. Travelling still towards the granite, glistening plates 

 of mica become apparent on splitting the rock, showing a new 

 phase of crystallization. Further on, the mica becomes more 

 plentiful, so much so as to be recognisable as alternating layers along 

 which the rock easily cleaves. While still nearer the granite the 

 now schistose rock exhibits a peculiar puckered and wavy surface 

 with a satiny sheen. Then dark spots make their appearance, 

 and knots, ovoid and round, stand out on the weathered planes. 

 These spots vary in size from a pin's head to a pea. In this we 

 have an excellent example of the interesting metamorphic slate 

 known as Knotenschiefer. Finally, a mass of rock is met with of 

 a dark blue colour, with no traces of schistosity in any direction, 

 forming a typical hornfels. This interesting succession of zones 



