PRE-CAPE ROCKS OF THE NORTH OF THE COLONY 89 



cline below Prieska ; where such sections are exposed 

 banded magnetic jaspers are found interbedded with the 

 upper layers of limestone in the Campbell Eand series, 

 and show that the change of circumstances which 

 caused such a striking difference in the nature of the 

 sediments was not sudden and final, but was completed 

 only after one or more recurrences of the formation of 

 the limestones. The contrast in their ways of weathering 

 is responsible for the fact that the passage beds are not 

 often exposed. The Campbell Rand limestones are 

 much more readily dissolved by water in the soil than 

 the siliceous rocks of the Griqua Town beds, but 

 they do not break up into small fragments like the 

 latter, hence the slopes of the escarpments are covered 

 by loose thin pieces of the jaspers, and the limestones 

 are usually first seen in large slightly curved surfaces 

 some distance below the junction of the two series. 



The lowest beds of the Griqua Town group are often 

 found to be sharply bent in various directions, while the 

 limestones below lie flat or at a low angle, and the 

 Griqua Town beds themselves at a varying distance from 

 their base are also very little disturbed and dip conform- 

 ably with the limestones. 



These phenomena have been noticed at many places 

 along the eastern escarpment of the Griqua Town series, 

 but especially near Daniel's Kuil, 1 and in the area of the 

 Maremane anticline. They have not been seen along 

 the south-west border of the formation, nor round the 

 small anticline below Prieska. The best exposures of 

 highly contorted rock are to be found in outliers of the 



l $eeG. C., xi., 35. 



