4 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 1, 



in the sketch. One of these dykes (P Q) ran nearly due magnetic 

 north and south, the other (R S) crossed it at an angle of about 50°. 



Fig. 2. — Sketch-plan of the Valley in which Gold was found in 



Southern Africa, 



■''^^f^l 



L, S. V Dykes of 

 ,U.J 



Stream. 



P, Q 



R 

 T 



trap-rock. 



A. Place of the jackal's hole where auriferous quartz was 



first found. 



B, C. Pits sunk in one of the dykes. 



D. Hole sunk in the gravel of the valley. 



Several parties had been engaged in digging on this spot ; and, on 

 turning up the masses of igneous rock, some fine specimens of cry- 

 stalline quartz were found, several of which, when broken, were found 

 to contain small nuggets of gold in their cavities. These masses of 

 quartz were peculiar in appearance *, consisting of a plate of opake white 

 quartz with masses of crystals growing from one side over that which 

 lies undermost in the earth. The gold was in the cavities of the plates. 

 It appeared to me that the plates were veinstones, which had been 

 detached in the decomposition of the dyke with its contained vein, 

 for, although I could not detect a regular vein, such as I shall have 

 to describe presently, yet I believe there was one, but the partial de- 

 composition of the surface prevented me tracing it. Just at the 

 junction (A), a mass of blue rock was found, some of which had been 



* I have never seen anything like them in the Colony, though quartz abounds 

 everywhere. 



