GEOLOGY OF THE NEIGHBOURHOOD OF STELLENBOSCH. 12/ 



and you will find the Table Mountain Sandstone descending on 

 the west side ever nearer and nearer to the river, while on the 

 east side it hangs high up in the air. Here we are clearly on 

 the line of a fault, or it may be a monoclinal fold, along which 

 the rocks on the west side have been dropped down some 1,500 

 feet. 



For further evidence, if any is required, of the existence of 

 a powerful dislocation along the line of Jonker's Hoek, one need 

 only look at anv of the small rock exposures in or about the 

 mouth of the valley. The granite has been sheared and crushed 

 along vertical planes with a N.W.-S.E. direction, and it is now 

 quite streaky in appearance ; the sedimentary rocks of the French 

 Hoek Series have suffered the same change to such an extent 

 that it is now very hard to recognize their original character ; 

 among them there occur bands of coarse conglomerate in which 

 the pebbles have been compressed and elongated. Whether the 



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fslS 



Fig. 2. 



dislocation is to be called a fault or a monoclinal fold is a matter 

 of little importance : it is probable that there are many parallel 

 small faults rather than one great fault. Nevertheless, we shall 

 not be violating' any convention if we speak of the Jonker's Hoek 

 Fault, meaning thereby the whole aggregation of parallel faults 

 and shear-planes. 



It is a matter of common observation that lines oi fault are 

 lines of relatively easy erosion ; hence the reason which imme- 

 diately suggests itself for the direction of the upper portion of 

 Eerste River is that the river discovered and folloived the line 

 of zveakness made by the Jonker's Hock Fault. We may sup- 

 pose the original consequent stream, with its S.W. direction, to 

 have cut its way back into the mountain mass of which Simons- 

 berg and the Stellenbosch and Ban Hoek Mountains are the 

 reninants, and eventually to have reached the line of fault 



