LTDENBURG AND DE KAAP, TRANSVAAL, SOUTH AFRICA. 579 



the ridge on the west side of the Dorps Pdver, striking IS'.iS'.E., and 

 having an easterly dip of about 80°. This reef is in a diorite dyke, 

 to the depth already proved of over 50 feet, and will yield gold at 



the rate of 9 dwt. to the ton* The shales and sandstones 



are highly metamorphosed throughout, but especially so where in 

 contiguity to the numerous dykes of diorite and other plutonic rocks 

 by which they are traversed in various directions. As a rule, such 

 dykes are more or less vertical in relation to the strata through 

 which they pass; but there are several on the town-lands that 

 almost if not quite coincide with the stratification." 



Six miles north of the town the Pilgrim's-Eest road winds down 

 a steep hill to the " drift " across the Spackboom E-iver. The road- 

 cutting exposes grey shales all the way down, except where they 

 are broken through and locally displaced by a diorite dyke, which 

 the section shows plainly in the various stages of concentric weather- 

 ing. The shales below the dyke are black, like slate in appearance 

 and composition, but without any sign of cleavage. (The absence 

 of true slate is somewhat remarkable. I have not yet seen it in any 

 part of South Africa.) 



e'. From Lydenburg the country and the beds rise to the east- 

 ward with a long " dip-slope," and a few miles in that direction lies 

 the " Paarde-Plaatz," or Horse-farm, belonging to the town. " The 

 rocks of Paarde-Plaatz are altered shales on the western margin, 

 which overlie a series of crystalline false-bedded sandstones that 

 crop out along the edge of the mountain, and form the higher grounds 

 in the centre and on the east side of the farm. These sandstones, 

 in turn, rest upon another series of shales that occupy the lower 

 grounds, and stretch away to the eastward" f. There are numerous 

 seams of quartz, varying from 2 to 18 inches in thickness, inter- 

 stratified with these sandstones and lower shales, and these wiU be 

 referred to presently, as they are rich auriferous deposits. There 

 are also vertical veins of quartz which contain gold. 



Paarde-Plaatz. — In June last year, when examining this ground, 

 I picked up a loose piece of crystalline quartz, very promising in 

 appearance, and in such a position that it must have come from a 

 reef within a short distance. It yielded gold at the rate of upwards 

 of 5 oz. to the ton. There was no sign of the outcrop of a true lode, 

 so trenches were cut under my direction, and by this means the 

 source of the loose lumps of quartz was discovered. It proved to 

 be a flat seam of red-brown crystalline quartz, perfectly interstra- 

 tified with the bedded rocks. Numerous other auriferous quartz- 

 seams coincident with the stratification were afterwards opened a 

 few feet apart in the shales and sandstones. These seams extend 

 over a considerable area, and vary in thickness from 1| to 18 inches, 

 and in yield of gold (some barren) from 9 dwt. 1 gr. to 6 oz. 17 dwt. 

 10 gr. per ton. The average of fourteen assays of stone from these 

 flat seams, and calculated upon their various thicknesses, is 3 oz. 

 6 dwt. 16 gr. per ton. 



'' For this and neighbouring reefs see the author's Report, Dec. 1884. 

 t Report, Sept. 1884. 



