123 



Thoroughly crystalline schists are first met with about a 

 mile west of Mount Barker Junction. They have the char- 

 acter of tremolite- and actinolite-schists, passing in places 

 into a perfect tremolite rock. Their strike is north and south 

 and their dip vertical. From Mount Barker Junction for 

 about one and a half miles east w^e have soft friable white 

 quartz schists, lithologically like those of the Mount Lofty 

 series. Structurally they appear to be members of the schis- 

 tose series, though it is possible they form an outlier of the 

 Mount Lofty beds infolded into the older rocks. 



About one and a half miles east of the Junction these 

 rocks are affected by a marked shatter-zone, and become 

 much veined with quartz. Approaching Nairne we pass 

 again to schists, which become spotted, owing to development 

 of incipient andalusite. This mineral increases in import- 

 ance until just to the east of Nairne Station the schist sliows 

 well-marked knots of it. Rocks of this type are widely 

 developed amongst the schists of South Australia, and as I 

 shall have to refer to them frequently I shall coin the name 

 '"Paringite" for them, after Paringa, a group of railway cot- 

 tages between Nairne and Callington, where they are typic- 

 ally developed. 



Paringite is a moderately coarse, friable, silvery, mus- 

 covite-biotite-schist, with very wavy lamination, and with 

 very prominent "knots" or "eyes" of impure andalusite, which 

 may be upwards of an inch in diameter. 



From the thirty-five and a half mile peg (about half a 

 mile east of Nairne) to the thirty-six and a half mile peg 

 the rocks (schist and quartzite) are much shattered, all the 

 evidence pointing to a zone of intense fracture. For some 

 distance east of the fracture-zone there is a notable discord- 

 ance between the dip of the beds and the dip of their cleav- 

 age planes. This discordance gradually disappears as we pass 

 eastwards, and is additional evidence of powerful earth move- 

 ment in the neighbourhood. 



There is no outcrop of quartzite in the railway section 

 at all comparable with the immense mass of Mount Bar- 

 ker. ^2) From the thirty-eight mile peg to about the forty-one 

 mile peg the character of the rocks is pretty uniform. They 

 consist of a thick series of mica schists, with occasional bands 

 of sericite schist. Their dip is very constantly about 

 E. 5 deg. N. at from 30 deg. to 40 deg. Several small faults 



(2) Mount Barker and Mount Barker town are nearly three 

 miles apart, so that there is considerable ambiguity in speaking 

 of Mount Barker. When the name is used in this' paper it will 

 refer to the mount itself; when the town is intended it will be 

 specified. 



