570 



relevant to the case in hand, inasmuch as the 

 uniform high angle of dip proves that the mount 

 forms no part of a monoclinal-fold. 



(c) A close-fold in an ■isoclinal series, in which the 



quartzite formed the central axis of the fold and 

 thereby became duplicated, would give double 

 breadth to the bed and a high angle of dip. 

 Such a scheme of tectonic structure does not, how- 

 ever, fit in with the surrounding features, as there 

 is little folding throughout the district, other than 

 a uniform pitch to the west on the western and 

 northern sides, and to the east on the eastern side 

 of the hill. 



(d) Pressure in a north and south direction on beds at 



a high angle might cause a vertical puckering, with 

 overlapping and thickening of the beds near the 

 centre. In the Mucra Ranges, near the Mucra 

 Springs, due east from Mount Remarkable and 

 two and a half miles west of the Black Rock rail- 

 way station, there are some very striking quartzite 

 outcrops that have been, under great pressure, 

 turned at right angles to the strike. While such 

 an occurrence is a possible explanation of the 

 thickening of the quartzite at Mount Remarkable, 

 no corroborative evidences were obtained that this 

 was the case there. 



(e) In looking for an explanation it must be remembered 



that the tectonic control of the region concerned 

 has been one of fracture, displacement, and read- 

 justment of the dissevered component parts. It 

 is, perhaps, most consistent with the surrounding 

 tectonic features to assume the existence of a 

 trough-fault (or several of these) with parallel 

 walls, by which segments of the quartzite were 

 successively dropped to lower levels, as shown in 

 fig. 2. The broken character of the quartzite 

 obscures the structure within its own area, but the 

 features pertaining to the outcrops are strongly 

 suggestive of a major line of fracture that follows 

 the crest of the ridge and has had the effect of 

 duplicating the beds. This view is supported by 

 the hi eh dip of the beds on the eastern side of the 

 summit, the great spread of the quartzite outcrops, 

 and the shattered condition of the stone. 



A doubt still remains as to the particular quartzite 

 which forms the core of the mount. As already intimated, 

 if the orderly succession seen on the western side of the 



