GEOLOGICAL RECONNAISSANCE OF THE STIRLING RANGES. 89 



In the lower slopes of Mount Hassell, fine, hard, purple 

 quartzite predominates. In the upper portions of this 

 conical hill, phyllitic layers become more pronounced, but, 

 throughout, the quartzites are very considerably in excess. 

 Current-bedding is very pronounced and ripple marking is 

 exquisitely developed. These ripples are all of the asym- 

 metrical type, 1 with small amplitude (about half an inch). 

 In numerous instances the small intermediate ridges 

 mentioned by Kindle are beautifully shown. Such ripple 

 marks undoubtedly indicate the action of strong currents 

 in very shallow water. At the western end of Princess 

 Royal Harbour, Albany, ripple marks in fine sand formed 

 by waves with a wave length of about three feet and an 

 -amplitude of about six inches, and in water not more than 

 from four to six inches deep, appeared exactly similar to 

 those in question. 



The phyllites interbedded with these ripple marked 

 quartzites rarely exceed four inches in thickness. They 

 are much more slaty in character than those described 

 above from the eastern peaks. They are smooth and not 

 puckered, and, although shiny and lustrous on the bedding 

 planes, do not show nearly so much development of mica 

 as do those of Ellen's Peak, etc. The beds of phyllite are 

 often considerably ruptured, and, near the summit, there 

 is a band of quartzite through which are scattered, irregu- 

 larly and not very abundantly, rounded and angular frag- 

 ments of phyllite. This structure recalls very strongly the 

 occurrence of disrupted shaly blocks in the Hawkesbury 

 Sandstone of New South Wales, and, in conjunction with 

 the marked development of false bedding and ripple marks, 

 suggests that the Stirling Range Beds, like the Hawkesbury 

 Sandstones are estuarine in origin. The rocks of the 



1 Kindle, E. M.— A comparison of the Cambrian and Ordovician ripple 

 marks found at Ottawa Canada. Journal of Geology, Vol. xxn, 1914, p. 

 703-713. 



