Yol. 54.] WITWATERSRAND AND OTHER DISTRICTS IN S. TRANSVAAL. 97 



the same character, and possibly identical with the fault jnst 

 described, exists in the eastern portion of the Simmer & Jack 

 Mine, and extends into the Rose Deep. This fault strikes to the 

 south-east, and dips south-west at an angle of 60°. The trace of 

 the fault-plane at the surface makes an angle of 37^ with the reef- 

 outcrop. The horizontal displacement is 650 feet, and the vertical 

 displacement about 400 feet. A considerable extrasion of igneous 

 matter has taken place along the plane of faulting (see fig. 5). 



Eig. 5. — Reversed fault hy the Great Simmer D'jhe, 

 in the Rose Deep, Witwatersrand. 



cX-" 



.^^ 



^" 



S.. . -'..*- .-vX' ,'•.--, .-'.7;>: 



< . t"' '\ *- V v-^//' 



Scale oF Feet 



lOO 200 30O ^00 



_1 I I- 



[The position of the reefs shown on the left of the figure is conjectural.] 



Another fault in the Metropolitan Mine caused a repetition of 

 the Main Eeef, so that the same reef was worked down from the 

 surface for several levels in two parallel stopes. Similar overthrust- 

 faults have been observed in many of the mines, as, for example, 

 the George Goch and Nourse Deep, the Crown Deep (fig. 6, p. 98), 

 Langlaagte Eoyal, Simmer & Jack, etc. On a property known as 

 the Eip, in the Western Hand, a series of parallel strike-faults causes 

 a four- or five-fold repetition of the outcrop of the Battery Reef 

 conglomerates. Instances could be multiplied, but sufficient has 

 been said to show that reversed faulting exercises an important 

 influence on the tectonic character of the Witwatersrand Beds.^ 



^ Compare also Gibson, Quart. Journ. Geol. Soc. vol, xlviii (1892) pp. 412 

 &428. 



a J. G. S. No. 213. 



H 



