125 



both sides are thoroughly metamorphosed and recrystallized 

 the granite, though somewhat foliated, is not very highly 

 altered, showing that, while it has suffered from some of the 

 later earth movements, it is very considerably younger than 

 the schists. 



Lying to the east of the granite there is a wonderful 

 variety of rock types, the normal schists having undergone 

 extensive contact metamorphism. The resulting rocks are 

 well exposed in the cuttings through Rocky Gully. Close 

 to the granite contact are highly crystalline quartz schists, 

 with bundles of radiating tremolite needles. These are ex- 

 tremely handsome rocks in hand specimen. They are suc- 

 ceeded by very coarse felspathic biotite schists, through which 

 are numerous veins of pegmatite; in fact, there is a regular 

 lit par lit injection in places. Some of the schists in texture 

 and composition approach gneisses. In one of the pegmatite 

 veins two small crystals of beryl were observed : this occur- 

 rence is interesting, from the fact that the same mineral 

 occurs in the very coarse pegmatites of Williamstown, thirty- 

 eight miles to the north-west. 



Between Rocky Gully and Murray Bridge no outcrops 

 other than eocene limestone are met with. As might be 

 expected, there is a very notable development of travertine. 



The road sections approximately parallel with the rail- 

 way will now be described. Along the road from Oakbank 

 to Woodside there occur schists generally similar to those 

 met with just west of Mount Barker Junction. These bound 

 the Onkaparinga valley on the east; on the w^est occur less 

 schistose quartzites and slates, the river following the junc- 

 tion between the two series for a considerable distance. 



The road section from Nairne to Callington via Dawes- 

 ley and Kanmantoo is also very interesting. For some two 

 and a half miles from the Railway Station at Nairne the 

 rocks are schists and quartzites similar to those encountered 

 along the railway line. Just to the east of the town is an 

 outcrop of quartzite lithologically similar to that forming 

 Mount Barker, but there is no trace of the. very strong fea- 

 ture formed by the Mount Barker escarpment. In a quarry 

 one and a half miles east of the town biotite schists are ex- 

 posed with a dip of W. 10 deg. S. at 85 deg., that is, in a 

 direction opposite to that of the dominant dips of the dis- 

 trict. It is probable that this reversal is caused by a very 

 sharp flexure, perhaps combined with faulting. A little far- 

 ther east the direction of dip is E. 10 deg. S. at varying 

 angles down to as low as 35 deg. 



At about two and a half miles from Nairne there occurs 

 a thin band of extremely tough, vesicular, blue slate like 



