Vol. 62.] IN THE SOUTH-WEST OF CAPE COLONY. 83 



localities mentioned lies on a flat plain, or one that slopes gently 

 towards the sea, and is terminated by an abrupt drop : — 



Feet 



East Eondon 151 



Cambridge 467 



Fort Jackson 1108 



Berlin..... 1638 



Blaney 1775 



Sterkstroom 4406 



Cypkergat 5450 



In the Transkei and Pondoland the coast-shelves are very strongly 

 marked. The main plateau is elevated about 2500 feet above sea- 

 level, and still, in a very few cases, retains masses of surface-gravel 

 and quartzite. One hill standing on the plateau, called Kentani 

 Tree Hill, where there was a fierce fight in the Gaika-Galeka war, 

 has an elevation of 2420 feet : the peculiar freshwater quartzite, 

 with the many-coloured clays and sands not yet consolidated by the 

 siliceous cement, and the conical shape which the small cap of hard 

 rock has given to the hill, have puzzled many generations of people, 

 both black and white. Not so very long ago it was declared a 

 diamond-pipe, and the whole white community in the district 

 resolved itself into a syndicate to work it. The general level of 

 the plain is some 500 feet below the level of the hard caps ; 

 for, although the whole area is covered with grass, there is a 

 vigorous denudation going on which is rapidly reducing the level 

 of the country. 



At Kentani village there is a cliff letting the plateau down 

 1000 feet, and thence by other steps to a low ridge only 50 to 

 100 feet above sea-level. In the neighbourhood of the St. John's 

 River the coastal geology becomes very complicated ; but in Eastern 

 Pondoland, where there is a simple shelf of Table- Mountain Sand- 

 stone, the subsidiary plateaux are as sharply defined now as when 

 they rose from the water's edge. 



The task of gathering together facts from levels carried out by 

 eye-surveys, with very few points fixed in height, cannot lead to 

 satisfactory results unless appeal can be made to more detailed 

 work. The reason why I have brought in these eastern plateaux is 

 to show, firstly, that plains of marine denudation do clearly exist 

 all along this coast ; and, secondly, that the level of the plains 

 observed at the various localities varies considerably. 



Table of Coast-Shelves in tue Cape Colony. 



Name of 



Shelf. 



Western. 



Midlands. 



Eastern. 





Feet 



Feet 



Feet 



Cyphergat 



50C0 to 6000 ? 



5000 to 6000 ? 



5450? 



Sterkstroom . . . 



3500 to 4000 ? 



4000? 



4406? 



Kentani 







2500 



De Ylugt 



1500 



1000 



1500 



Uplands 



700 



463 



467 



Bamboes Bay . . . 



50 to 100 



200 



157 



Sea-level 



— 



— 



— 



Agulhas 



-600 







Native 



Territories. 



Feet 



4500? 



2500 



v 1500 



600 



50 to 200 



G-2 



