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leading to the N.N.E. appear about the thirty-nine and a half 

 mile peg. For more than a mile east of the forty-one mile 

 peg the dips again become disturbed, and another fracture- 

 zone is suggested in the neighbourhood of the railway cot- 

 tages at Paringa. The rocks are thrown into sharp folds. 



At about forty-two and three-quarter miles from Ade- 

 laide another belt of paringite occurs. It is quite possible 

 that there may be two or more distinct horizons of this rock, 

 but I think it more probable that a single belt of it has 

 suffered repetition through heavy strike faults or by folding. 

 From this point to Callington the rocks are chiefly tough 

 mica- and chlorite-schists. At Callington itself the schists 

 are strongly mineralized, and the Callington Mine was at 

 one time an important ore-producer. There is a wide break 

 in the section here caused by the valley of the Bremer River, 

 which occupies a broad U-shaped valley. On the eastern 

 slope of this valley there is a very considerable area of sand- 

 dunes. These I think rejjresent the advanced guard of the 

 Lake Alexandrina beach sands moving northwards along the 

 Bremer valley. Above the reach of the sand here the rocks 

 exposed consist of dark and very tough biotite schists, with 

 high angles of dip towards the E.S.E. These form a ridge 

 separating the Bremer valley from a much wider one in 

 which Monarto lies. This valley, though possessing a well- 

 defined north and south trend, is not occupied by a stream 

 like the Bremer. The absence of a stream is to be accounted 

 for by repeated captures by small streams running direct to 

 the Murray, as, for instance, the Rocky Gully Creek, through 

 whose gorge the railway line passes. 



Like the Bremer Valley, this one is much filled with 

 drift sand, which hides the bed-rock from view. Where the 

 sand-drifts have been stripped there are large areas of solid 

 ringing travertine. This formation, almost ubiquitous in 

 South Australia, is conspicuous by its absence or rarity in 

 the area between Nairne and Callington. In this area it is 

 prevented from forming partly by the comparatively high 

 and well-distributed rainfall, but mainly by the low lime 

 content of the schists. Its conspicuous developments near Mon- 

 arto, and thence, in patches, east to Murray Bridge, is due 

 to the occurrence of thin patches of tertiary limestone lying 

 on the upturned edges of the schists. The latter outcrop 

 at intervals over the floor of the valley, but do not give rise 

 to conspicuous features there. About two and a half miles 

 east of Monarto Station is the western boundary of a strip 

 of granite intrusive into the schists. Though this granite 

 has a considerable north and south extent, its width from east 

 to west is very little over one mile. While the schists on 



