Diorites and Granites of Siviffs Creek, 73 



PAET II 



4. The Alluvial Gold Deposits. 



The alluvial gold workings have been carried on from the 

 junction of Eureka Creek and Swift's Creek to the junction 

 of the latter with the Tambo River: also in the Sheep 

 Station Gully and in Riley's Creek, throughout almost the 

 whole course of the latter. These deposits are now almost 

 exhausted by the mining operations of the last twenty-five 

 years. They were confined entirely to the stream bed, and 

 more rarely to the points of the spurs. In tracing down 

 Swift's Creek proper from Eureka and to near Tongeo West, 

 I have found that the stream flows along the contact of the 

 intrusive and the sedimentary rocks, and that it has cut 

 down along this contact, whose plane dips at an angle of 

 perhaps about 30° to 45° to the west. The streams which 

 join Swift's Creek in this distance from the west flow only 

 over sedimentary or metamorphic formation, and have not 

 been found sufficiently auriferous to pay for working 

 excepting in places near their junction with the main 

 stream ; and here the gold seems to have ceased in passing 

 from the contact into the area of the altered slates and 

 sandstones, as at Eureka. This points, therefore, to some 

 connection between the contact of the intrusive and 

 sedimentary formations and the source of the gold. 



From Tongeo West to the Tambo River, Swift's Creek flows 

 within the somewhat metamorphosed Silurian strata, and at 

 an increasing distance from the intrusive granites, which 

 are, however, most certainly situated at no great depth 

 under foot. A connection between the gold and the 

 intrusive rock masses is not so evident in this part of the 

 district. 



On leaving Swift's Creek and following up Riley's Creek 

 it is found that gold has been extensively mined for in the 

 stream for some distance above where the contact crosses it. 

 A very rocky and precipitous part of the stream's course 

 then ensues, in which little or no gold has been found. 

 Near the junction of Sheep Station Gully with Riley's Creek 

 the tableland known as the Gum Forest commences, and the 

 fall of the stream being more moderate, gold has been 



