242 



Anstey's Hill is a prominent spur of the Mount Lofty 

 Ranges, situated a mile and a half, in a direct line, north of 

 the Torrens Gorge, and is traversed by the main road between 

 Paradise and Houghton. It exhibits a thick series of quartz- 

 ites, which in structure and composition bear a close resem- 

 l)lance to the thick quartzites which occur in the other locali- 

 ties referred to above. The cvittings on the road, as well as 

 numerous quarries, give excellent sections of the beds. The 

 beds dip east, or a little south of east, varying from 50'' to 

 70^, which they maintain in a direction across the strike, for 

 about a quarter of a mile, indicating great thickness. The 

 outcrop is continuous to the River Torrens, and forms the 

 precipitous hill on the north side of the waterworks weir. 



On the east side of the great curve in the road, w^hich 

 goes around the north side of the hill, the quartzites take a 

 lower angle of dip, and just before they disappear are hori- 

 zontal, or perhaps have a slight dip to the west. There, is 

 liere a sudden change to 2Dh3dlites, with miich thrust to the 

 west. From the dip of the quartzites these phyllites should 

 overlie them, and the ''blue metal" beds, which outcrop a little 

 higher up the road, point in the same direction. The phyl- 

 lites are greatly disturbed, and it is probable that they are 

 faulted against the quartzites. The relationship which the 

 Anstey's Hill quartzites bear to a parallel ridge of similar 

 stone on the eastern side is referred to under Section V. 



The Black Hill, situated at the entrance of the gorge of 

 the Fifth Creek (Montacute road) forms the greatest mass 

 of quartzite in the Mount Lofty Ranges. Its steep sides and 

 flat top, covered with a sombre scrub vegetation from top to 

 bottom, makes it a conspicuous object from the plains, and 

 has secured for it the appropriate name of the Black Hill. 

 The hill rises 1,000 feet* above the plain, and consists of quartz- 

 ite throughout. The stone is divided up into compara- 

 tively thin beds, separated from each other b)^ partings of a 

 more or less shaly nature. These partings consist mainly of 

 sand grains mixed with thin laminae of silicates, which give 

 evidence of much shearing. There has evidently been con- 

 siderable movement along the divisional planes, which would 

 be planes of weakness under stress. Quartz has been develop- 

 ed, more or less, in these partings, and in a few instances a 

 slight evidence of pegmatitic structure was recognized. In 

 the Government quarry [Stone Reserve^ Section 304, Hundred 

 of Adelaide], about a quarter of a mile from the mouth of 



* As near as can be judp^ed from data kindly supplied by the 

 Surveyor-General's and the Engineer-in-Chief's JDepart-mentf;. the 

 Black Hill is 1,540 feet above sea level, and 1.140 feet above the 

 plains at its base. 



