110 Transactions of tlie South African Fhilosophical Society. 



the old shore-line of the continent that existed in Permian timeSy 

 which afforded the sediments for the Dwyka Conglomerate and 

 succeeding strata. 



It is interesting at this stage to notice the change of sediment that 

 resulted from the degradation of this old continent from the times 

 when it rose in mighty mountains towering above the snow-line, 

 although so near the Equator, and glaciers, with their peculiar 

 morainal matter, crept down their sides ; through times when, in 

 the course of ages, the effects of weathering had cut the mountains 

 down so that snow no longer accumulated on them, and the 

 climate of the continent became more genial, the rivers discharged 

 sediments which now^ form the Ecca shales, characterised by abun- 

 dance of vegetable life ; to the time w^hen the continent became hot 

 and the Karroo reptiles multiplied on the land, and sediments 

 peculiar to shores off tropical lands were deposited. 



The third step depends on w^hat becomes of the sediments 

 deposited off the shores of continents. It is by no means univer- 

 sally accepted, but tlie view is every day gaining in favour that the 

 crust sinks under the weight of accumulated sediments, and cer- 

 tainly we have the fact that the sediments from the Dwyka 

 Conglomerate to the Upper Karroo are bent into a basin-shaped 

 form : this can only have happened by the crust bending ; but the 

 question whether this is due to surface being weighted by the sedi- 

 ments or to some other cause I will not now" enter upon, but for the 

 sake of brevity I will take it that the crust did sink under the 

 weight. The sediments from the old north-western continent went 

 on accumulating ; sinking allow^ed a vast amount of material to be 

 deposited, but finally the sea became very shallow. It was about 

 this time that the great dykes and sheets of dolerite were intruded 

 into the Karroo Beds, and the sediments, up to the Upper Karroo, 

 were lifted above the surface of the water and became dry land. It 

 was on this new land that the first river system was developed as 

 explained previously. The new land formed a fringe of some 100- 

 150 miles broad running parallel to the old shore-line. 



We come now to the question of the Stormberg Beds, which were 

 deposited outside this new land. Are the Stormberg Beds made up 

 of sediments such as we should expect from the degradation of a 

 land formed in the manner we have just described ? The sediments 

 from such a land would consist entirely of very fine detrital material, 

 as it is itself entirel}- formed of fine debris from the waste of the 

 old continent. 



The Stormberg Beds are certainly formed close in shore. The 

 muds which occur in the series are full of the most perfect remains 



