Reviews — Geology of South Australia. 373 



have been first noticed in 1852, a year after the discovery of such 

 marvellously rich auriferous deposits in the adjacent Colony of 

 Victoria, which has since become so famous for its gold-fields. 



The district of Echunga does not appear to have ever realized 

 the ardent expectations of those whose only ambition seems to be to 

 get rich in haste. Between 30 and 40 claims have been taken up 

 and worked, sometimes by individuals, sometimes by companies ; the 

 Government appears also to have employed the services of prospectors 

 and to have paid over £1000 in bounty money to successful explorers. 



No regular returns seem to have been kept, and after a reef or 

 gully proved unprofitable, it was abandoned, and no record left of 

 the actual results. It is, however, believed that the total amount 

 of gold raised since 1852 has been large. 



1. Most of the area (about ten miles long by six miles wide) is 

 composed of Lower Silurian rocks consisting of conglomerates, grits, 

 quartzites, sandstones, clay-slate, micaceous-slate and sandstone, mica- 

 schist, etc., with accompanying felspathic decomposed dyke-like 

 masses, and decomposed greenstone and granite veins. 



In this the quartz-reefs and payable gold-diggings occur, extend- 

 ing for nearly the entire length of the area. 



2. Sands, clay, gravel and conglomerate of Pliocene age and of 

 variable thickness compose the Older Gold Drifts, and occupy a very 

 considerable area in the central, western, and southern parts. 



3. A smaller area is covered by cappings of sand, clay, gravel, 

 etc. (generally at a higher level than the alluvium), believed to be 

 of Newer Pliocene age. These deposits occur along the river at 

 various places, having apparently escaped being denuded ofi". They 

 form the Middle Gold Drift. 



4. Lastly, the gullies and flats are occupied by alluvium, clay, 

 sand, gravel, etc. This forms the Upper Gold Drift of Post- Pliocene 

 age. Mr. Brown observes that besides the auriferous channels 

 gutters, and basins which have been worked out here, it is probable 

 that many others exist, which can only be discovered by sinking 

 trial-holes here and there, where the ground has not previously been 

 prospected. 



In the case of the large Tertiary valley which extends from 

 near Hahndorf southwards in the direction of Meadows, and 

 which is wider and deeper and at a lower level, it is probable that 

 much water would be met with in sinking in the deep ground. To 

 prove it, a series of shafts should be sunk across the valley, so that 

 the position and nature of the deep ground might be ascertained. 

 Judging by the character of the rocks forming the ranges bounding 

 this area, and the auriferous nature of the country generallj^ there 

 is every reason to expect that a payable auriferous lead exists here. 



The Map which accompanies this Memoir is a large one (scale 

 80 chains=l mile) — about two inches to a mile — and is very care- 

 fully executed, and well suited to the needs of a large mining 

 district. A very full list of references to exact spots at which the 

 rocks and minerals have been examined and determined accompanies 

 the map. 



