278 Revietcs — Geological Survey of S. Australia. 



EE7IE W S. 



Geological Survey op S. Australia. 



Beport on the Geological Character of Barossa and Para 

 Wirra, South Australia. 

 Notes, etc., Explanatory of Parliamentary Paper No. 178, with a 

 Geological Map of Pira Wirra and Barossa Reserves.!! By 

 Henry Y. Lyell Brown, E.G.S., Government Geologist, assisted 

 by Harry Page Woodward, P.G.S. Folio. (Adelaide, 1886.) 



The Barossa and Para Wirra Goldfields. 



The Barossa goldfield is situated in the south-west corner of the 

 hundred of that name ; it is separated from the Humbug Scrub gold- 

 fields only by the South Para River, which latter is also included in 

 the map. It was discovered in October, 1868, by Job Harris and 

 mates, who found gold in the gully now known as Spike gull} 7 . This 

 gully is about one mile and a half long — the prospector's claim being 

 near the middle. 



The depth of sinking was from 5 ft. to 20 ft., and some of the claims 

 were very rich, yielding as much as £1000 per man. 



The general features are a main rocky range, running from north to 

 south, of which Mount Gawler, near the south end, attains a height 

 above the sea of 1789 ft. This range is flanked on either side by 

 patches of Tertiary deposits, on the spurs between which the gullies 

 descend gently into Malcolm's Creek on the east, and through steep 

 rocky gorges into the Little Para, Gould's and Tenafeate Creeks on the 

 west. The north end of the reserve, in Barossa, is divided from that 

 in Para Wirra by the deep rough gorge of the South Para Biver. Here 

 the main ridge runs north-west and south-east, following the course of 

 the river, and being capped on its highest part by Tertiary beds, with 

 its small steep gullies running south into the Para Biver, and north 

 down a gentle incline into the Yetti Creek. 



The rocks of this district are supposed to be of Lower Silurian age, 

 from their lithological resemblance to those of the Yictorian goldfields, 

 although from their highly metamorphic appearance, and no fossils 

 having been found, it is impossible to say decidedly of what age they 

 are. In several places intrusive granite dykes are met with, and in 

 one particular line, from Malcolm's Creek to Mount Gawler, they are 

 very frequent. 



These rocks consist of metamorphic argillaceous and micaceous 

 schists, slates, sandstones and grits, granite, gneiss, hornblende schists, 

 mica schist and quartzites with granite, greenstone, and felspathic 

 dykes. As a rule they have a uniform strike of about 20° east of 

 north, and dip to the eastward from 35° to 70°; the only exception to 

 this rule seems to be near the Bismarck diggings, where the dip is 70° 

 west in two places ; but this is probably caused by local agency, as it 

 does not extend far. 



Nearly all the rocks of this district, especially on the ridges, have 

 so highly weathered an appearance, and are so decomposed, that they 

 might often be taken for Tertiary cements, particularly some coarse- 

 grained metamorphic granites, which contain a great deal of iron. The 



