GEOLOGICAL RECONNAISSANCE OF THE STIRLING RANGES. b< 



levels. The predominant colour is purplish or liver coloured, 

 though greys and blues are also quite common. For the 

 most part the quartzites are fine in texture and extremely 

 tough, and show very little trace of metamorphism. The 

 slates in many places approximate to the condition of shales, 

 so little are they altered. Very seldom is secondary 

 cleavage, transverse to the original bedding, developed; 

 but minute examination usually shows a very fine puckering, 

 and an incipient development of mica which is sufficient to 

 distinguish the rock as a slate rather than a shale. Over 

 the greater part of the area this characteristic of very 

 slight alteration is to be observed. Locally, however, a 

 much greater degree of recrystallisation has occurred, and, 

 in places, the rocks are intensely metamorphosed. This is 

 very notably the case along the southern margin of the 

 eastern section of the ranges. As above noted this margin 

 runs in a strikingly rectilinear manner from near the 

 mountain indicated as "The Wedge" to Ellen Peak and 

 Andrew Hill at the eastern extremity of the range; and, 

 throughout its entire extent, presents a very steep face 

 towards the southern plains. This fact alone indicates the 

 probability of the occurrence of a fault plane, and other 

 evidence in favour of this supposition will be adduced below. 

 At the Wedge the most intense alteration seen by me 

 occurs. The liver coloured quartzites of the rest of the 

 range are represented by thorough quartz schists, while 

 the interbedded slates have been converted into corrugated 

 mica schists. At Ellen Peak the degree of alteration is 

 less, but, even here, is sufficiently intense to have con- 

 verted the slate into phyllite with wavy structure and 

 silvery lustre. Here, the finer textured beds predominate 

 though they are interbedded with quartzite which has not 

 been altered, as at the Wedge, into quartz schist. The 

 whole series at this point is, however, very much veined 



