INTRODUCTION 7 



coast. They range from Neocornian to Danian in age, 

 though the succession is very incomplete so far as it is 

 known. These rocks include the only fossiliferous 

 marine mesozoic beds yet found in South Africa, 

 shelly limestones, conglomerates and argillaceous shales, 

 evidently formed near a shore. There are other rocks 

 in this system, conglomerates, sandstones, and clays, 

 which contain no fossils or only those of land or fresh- 

 water organisms, and these are the more widespread of 

 the two classes. 



The recent and sub-recent deposits probably date back 

 to Tertiary times, though some of them are in process 

 of formation to-day. They cover wide areas in the 

 south, west, and north of the Colony, but the eastern 

 districts are comparatively free of them. There is no 

 need to give further details about them at this stage. 



The geological structure of the Cape Colony divides 

 it into two parts, 1 a northern region in which the strata 

 have not been disturbed by earth-movements on a great 

 scale since Palaeozoic times, and a much smaller south- 

 ern region which has been the scene of mountain build- 

 ing and faulting during the Mesozoic period. The 

 transition zone between these two regions is curved ; 

 starting from the south-west near the Cape Peninsula 



1 The triple division of the Colony into Pre-Cape Region, Folded Belt 

 and Karroo Region adopted in the first edition of this book is now 

 abandoned, because it has become unsuitable owing to the fact that the 

 Karroo rocks cover a much wider area north of the Orange River than 

 was then suspected. The Pre-Cape Region of the threefold division be- 

 comes larger merely by the removal of the covering Karroo rocks by de- 

 nudation. The present twofold division has the advantage of being based 

 on one structural feature of importance. 



