86 THE CAMPBELL RAND SERIES 



made of a thick sheet of the limestones dipping west- 

 ward at low angles under the Griqua Town beds of the 

 Asbestos Mountains. The area of the Kaap Plateau is 

 some 6,000 square miles, and it has a remarkably flat 

 surface, though its height varies from about 4,000 to a 

 little over 5,000 feet. It is a good example of a " pene- 

 plain," and its origin will be discussed later. The sur- 

 face of the plateau becomes more and more sandy 

 towards the north, and near the Mashowing Valley it is 

 covered by a deep layer of sand, which persists over 

 nearly the whole of the rest of the area occupied by this 

 formation north of the Mashowing. The width of the 

 limestone belt is only twenty miles near the Orange Kiver, 

 south of which it is to a great extent covered by Karroo 

 beds, but northwards it gradually broadens till it reaches 

 a width of some eighty miles near Vryburg, when it 

 contracts rapidly to twenty-four miles along the Ma- 

 showing and maintains that width past Morokwen ; north 

 of that area it is buried beneath superficial deposits, but 

 curves towards the east and may join up with the 

 Dolomite formation of the Transvaal. This great band 

 of limestone is the western limb of a broad and gentle 

 anticline, the axis of which is occupied by the Vaal 

 River, and the eastern limb lies in the Transvaal and 

 under the Karroo beds in the Orange River Colony. 

 The formation reappears to the west from under the 

 Griqua Town beds in the Maremane anticline, of which 

 the northern end is buried under sand ; in the Wilge- 

 boom anticline traversed by the Orange Eiver below 

 Prieska ; on the south-w r est flank of the Griqua Town 

 beds in Prieska and Hay ; and at one place in the 



