76 Diorites and Granites of Swift's Creek, 



These pseudomorphs polarise as bright-coloured aggre- 

 gates. In examining these aggregates in the thinnest parts 

 of the slices I found them to be filled in those interstices 

 which may have represented planes of cleavage by numerous 

 black or dark green flocks, the nature of which I could not 

 determine, but suspect to be chlorite. The quartz granules 

 contain countless numbers of minute cavities. They mostly 

 contain fluid, and some have minute bubbles. Some cavities 

 are, however, evidentally empty. I observed also many 

 undeterminable microliths. The rock is strongly impregnated 

 by ordinary pyrites in modified forms of the cube. This 

 rock has, I think, been subject to great alterations, of a 

 character different to that of surface decomposition. 



In the quartz which forms the gangue of this mine I 

 found arsenical and ordinary pyrites, and galena, as also 

 small amounts of zinc blende. 



According to Mr. Easton, of Omeo, who was well 

 acquainted with the mine when being worked, the " shoot of 

 gold" was from 30 to 40 feet along the course of the reef 

 and dipped north at 66° — 70°. It yielded from one to two 

 ounces per ton of stone. He informs me also that the 

 shoot was followed downwards to a depth of 130 feet when 

 the workings were discontinued. The high yield quoted 

 by this gentleman seems at the first glance to be incon- 

 sistent with the tabulated statements ; but an examination 

 of the mine showed me that much poor stone had been 

 taken out far beyond the shoot of gold, and, in fact, a 

 great amount of work done and money expended uselessly. 



Rob Roy Reef. — This is situated at no great distance from 

 the Eureka and Black Prince Mines, and immediately upon 

 the contact line. The reef crops out along an extremely 

 steep spur between the Sheep Station Gully and Eureka 

 Creek. Adits have been driven at various times into the 

 hill along its outcrop. The workings which were in opera- 

 tion when I visited the mine last were carried on by two 

 adits. In the upper one the average thickness of the quartz 

 vein was 6 inches. Generally speaking the reef has quartz 

 diorite on one side and. highly altered contact rock on the 

 other, and underlies west at about 78°. To the southward 

 where the reef leaves the contact and is wholly in the 

 quartz diorite, it narrows to 2 inches, becomes poor, and then 

 dies away. 



The main workings at the time of my visit were in the 

 lower adit about 100 feet below the surface, the width of the 



