561 



The purple-slates on the southern side of the fault exhibit 

 extraordinary features of crush and are mylonized over a 

 very wide area. The mash -rock ( 5 ) forms hills several hundreds 

 of feet in height (especially in its extension westward), and 

 can be traced southwards from the fault-plane for a consider- 

 able distance. A section across these mashed beds can be 

 followed up Rankine Creek, and irregular and humpy out- 

 crops occur in the bed of the Mount Creek, near the bottom 

 of the path from Bartagunya. 



(d) THE PURPLE-SLATES ON THE EASTERN SIDE OF THE MOUNT. 



The purple-slates, with interbedded thin quartzites form 

 the outer range of the foot hills at Melrose. On the left bank 

 of the Mount Creek, behind the township, are two quarries 

 that are worked for road metal, but the stone is of inferior 

 quality for this purpose. In the upper quarry the stone 

 consists of white to reddish, rotten felspathoid quartzite and 

 arenaceous slates; while that of the lower is little more than 

 a kaolinized slate. The beds dip E. at 88°. In both quarries 

 the stone shows ripple-marks on the face of the bedding (a 

 very conimcn feature of the purple-slates in general), and in 

 the lower quarry of the two they appear on almost every 

 surface of bedding exposed. A well sunk at the side of the 

 creek, between the two quarries mentioned, is in yellow, 

 rotten slate, but has no great supply of water. 



A little higher up the stream a transverse section of the 

 slates can be seen in the banks where the beds dip easterly 

 at 65°, and almost immediately above. this outcrop is "Saddle 

 Hill," which consists entirely of beds of this series. At the 

 end of the hill, abutting on the Cathedral-rock Creek, the 

 beds dip E. at 53°. These readings prove that the angle of 

 dip increases as the beds approach the scarp face of the foot 

 hills adjacent to the plain. 



Continuing southwards, the purple-slates follow the 

 eastern boundary of the main limestone, and extend in an 

 easterly direction beyond the Survey road. On this road 

 typical examples of these slates are exposed in a small quarry 

 by the road side, about one mile south from Melrose. The 

 slates in the quarry are very fissile and have a dip E. 10° S. 

 at 50°. Purple-slates and quartzites can be recognized in 

 the adjoining paddocks, showing a slightly higher angle of 



'3) The term "mash-rock" is used with reference to the broken 

 up slates, and "crush-rock" for the brecciated limestones and 

 quartzites, the slates having been more finely broken up than the 

 limestones and quartzites ; but the difference in this respect has 

 probably been determined by the relative hardness of the different 

 rocks and their respective powers of resistance to the crushing 

 force. # 



