LTDENBTJRG MUD DE KAAP, THAIsSVAAL, SOUTH. AFEICA. 573 



although "it is also more rarely met wilh in. the form of grains in 

 the shales and other unaltered stratified rocks " * : and " bands of 

 different kinds of iron- ores are said to occur in some of the clay- 

 ironstone interstratified with the slates, and associated with these 

 are certain conformable beds, from ^Yhich the greatest riches of gold 

 have been obtained " t. 



Mr. J. A. Phillips (quoting Mr. E. B. Smyth) says : — " Gold is now 

 found to occur not only in the quartz-veins and in the alluvial deposits 

 derived from them and the surrounding rocks, but also in the clay- 

 stone itself: and, contrary to expectation, flat bands of auriferous 

 quartz have been discovered in dykes of diorite, which intersect the 

 Tpper Silurian or Lower Devonian rocks. Quartz of extraordinary 

 richness has been obtained from these bands " J. In the former case, 

 bands are said to occur, but would appear to be exceptional ; in the 

 latter the flat bands are in dykes of diorite, therefore veins, and not 

 beds at all. The auriferous beds now described are numerous and 

 rich, in both the Silurian (?) and Devonian (?) formations, and 

 possess an additional interest from their (so far as I am aware) 

 novel mode of occurrence. 



One side of the quartz seam called " Moodie's Reef," which would 

 be its north wall if a true vein, but is what was originally its under- 

 side as a bed, is plentifully sprinkled with specks of gold, rather 

 fine, but still quite visible to the naked eye. There is gold also in 

 the body of the quartz ; but, so far as I have been able to ascertam, 

 only in small quantity. The abundance of the metal on one side 

 must, however, give a good average yield of gold per ton. On the 

 same side of the quartz there is also a streak of green mineral, not 

 carbonate of copper, which at first sight it resembles, but probably 

 chlorite or some form of serpentine, traces of which are also apparent 

 in the body of the quartz. 



There are other seams of auriferous quartz in the immediate 

 vicinity ; some of these, discovered before the time of my visit, did 

 not come under mj- notice — others have been opened since, and 

 some of them, the " Ivy Eeef " for example, are said to be very rich 

 indeed in gold. 



h. Some miles east of Moodie's Reef the " Umvoti Reef" occurs as 

 a seam of dark-grey quartz, sometimes almost black and flint-like 

 in appearance. This seam is also in the bedding of the rocks, which 

 are hard dark-coloured schists, quite vertical, but here striking to JST.E, 



The " Umvoti Reef '' is also a seam (in the bedding) of dark- 

 grey quartz, varying from 6 to 12 inches in thickness, and contains 

 fine gold ; the sample assayed by myself, and in which no gold was 

 visible, yielded the metal at the rate of 16 oz. 13 dwt. 8 grs. to the 

 ton §. 



c. "Barber's Reef" is close by the Umvoti, but appears to be a 

 true lode, as it is transverse to the strike of the stratified deposits. 



* Jukes's ' Manual of Geology,' 3rd edit. 1872, p. 303. 

 t Ibid. p. 305. J ' Elements of MetaUurgy,' 1874, p. 693. 



§ Described in the author's Eeport, November 1884, as yielding gold in the 

 proportion of from 1 to 140 oz. per ton of 2000 lbs. 



