69 



At about half a mile from the road the ridge is suddenly 

 broken and twisted over a distance of 150 yards, when the 

 beds again form a ridge as an isolated hill : strike N. 20° W. 

 (dip W. 20° S. at 28°). The ridge is mainUined for about 

 200 yards, when it ends abruptly — cut by a fault — while the 

 limestones are thrown at nearly right angles to their former 

 direction: strike E. 10° S. (dip at 35°). So far as the beds 

 could be followed, by sight, they continue on the same strike; 

 then, at a mile distant, they appear to curve round towards 

 the east, or some point south of east. 



Starting again from the Oholella bed that crosses the 

 road to the old station, 3^ miles from the present Wirrealpa 

 Station, going north, a limestone ridge forms the foot hills 

 of the main escarpment range, and has its strike in the 

 direction of the old station, and appears to be faulted. A 

 very much brecciated limestone occurs between this ridge 

 and the great Archaeocyathinae limestone which outcrops in 

 the creek, a little higher up, where it is exposed in great 

 spheroidal masses. The brecciated limestone (which shows 

 bedding planes) has a dip W.S.W. at 50°, and contains 

 angular fragments of purple quartzites, etc. 



XII. The Old Wirrealpa Station. 



At the old Wirrealpa station (7 miles north of the present 

 station) there is a great show of tlie Archaeocythinae lime- 

 stone series, making 100 yards of outcrop : dip W.S.W. at 55°. 

 There is an extraordinary break up of the rocks which are 

 seen in the Wirrealpa Pass. The great quartzite range, which 

 forms a high peak at Wirrealpa Hill, comes to an abrupt 

 end near the old station buildings, and the beds in the valley, 

 as well as much of the thick limestone on the opposite side, 

 have been reduced to a breccia. Towards the centre of the 

 valley the beds are mostly quartzitic, and are so crushed that 

 they form a fault rock of great width. The great quartzite 

 hill disappears — cut off by a fault — on the north-eastern side 

 of the station ; the limestone on the opposite side of the valley 

 forms a conspicuous peak, which can be seen from a great 

 distance. 



At the old station the beds dip to the S.W. Following 

 up the creek the beds make a curve. At half a mile distance 

 they dip W. 10° S. at 35°; then a little further, the lime- 

 stone gives a reading of W. 20° S. at 75°, which has the 

 appearance of being almost at right angles to the dip of a 

 conspicuous hill (marked "First Hill" on map), with lime- 

 stone near its summit, situated in a direction to the S.S.W. 

 As near as could be determined, the beds of this distant hill 

 have a dip W. 20° N. at 40^ 



