426 PRE-MATSAP DENUDATION 



though some beds in the upper part of the series are 

 green slaty rocks unlike any found below. The source 

 of the sediments in the Griqua Town series, including 

 the glaciated boulders, is unknown. 



At the top of the Transvaal system in Cape Colony 

 there is a marked unconformity ; the rocks of that system 

 must have formed dry land for a considerable period 

 after their deposition, for thsy were in places partly or 

 entirely removed when the next group of rocks, the 

 Matsap series, was laid down. It is likely that the 

 region of the Maremane anticline in Hay and Kuruman 

 was to a large extent in its present condition at the 

 commencement of the Matsap period, for the peculiar 

 Blink Klip breccia, which is confined to that region, is 

 older than the Matsap beds, and nearly or quite the 

 whole of the Griqua Town series had been removed by 

 denudation along the Gamagara ridge before the basal 

 Matsap conglomerates were formed. There is a great 

 divergence in trend between the folds south of the 

 Orange Kiver in Prieska, which affect the Transvaal 

 system (north-west), and those which also affect the 

 Matsap series (north-east), but it is probable that the 

 two sets of folds were produced at about the same time. 1 



The Matsap series consists chiefly of coarse sandstones 

 and quartzites with remarkably well-rounded grains. 

 Though isolated pebbles are found throughout the 

 greater part of the formation, beds of conglomerate 

 are of exceptional occurrence ; they are only known 

 from the base of the series. Some of the pebbles in 

 these conglomerates are of local origin. 



1 See G. C., xiii. 



