440 



Notes on South African Geology. By Mr. Grisbrook. 





I believe it is not generally known that the eastern bank of 

 the Zwart-kop River,* together with the banks of the Zondag 

 River, are rich in marine petrifactions; a variety of shell 

 and vegetable fossils have been collected from the latter place 

 by Dr. Gill; the former was investigated by Mr. Von Bucken- 

 roder and myself, in the year 1828, on which occasion we 

 procured some very fine specimens. 



Martial-pyrites have been discovered in the Zwart Rug- 

 gens, t imbedded in a bluish shistone or clay-slate formation : 

 a varietv of opake-quartz is also to be found within the same 

 limits, and a coarse impure kind of agate (inferior to those of 

 the Orange River) has been discovered by Dr. Gill. 



Bruintjes Hoogte is celebrated for crystallised hexagonal 

 quartz, one splendid specimen procured from it, with a fluid 

 in the centre, has been sent by Dr. Hoistok to Professor Lich- 

 tenstein, at Berlin. 



The Sneeuwbergcn and intermediate country, are famous 

 for mineralized substances; carbonate of lime, and the beauti- 

 ful green mineral called Prhenite, being numbered among the 

 variety; native saltpetre is found in many places within the 

 same district. 



The Orange River is celebrated for agates, and a vast va- 

 rietv of crystallized and siliceous substances; amianthus is 

 also procured from the same quarter. 



Mineral-springs abound in different parts of the Karroo, 

 particularly in the vicinity of Beaufort. 



The celebrated Caverns in the Cango, are noted for large 

 and grotesque masses of crystalline carbonate of lime. 



The Cedar-Mountains, District Clan William, together with 

 the adjacent country of the Bokkeveldts, are rich in organic 

 remains: it is principally from this source that our colonial 

 geologist, Dr. Thorn, has collected the major part of his 

 splendid and valuable cabinet. 



•The borders of the Oliphants River, below Clan William, 

 abound in excellent lime-stone ; the inhabitants of the neigh- 



• Both these rivers are situated in the District of Uitenhage, and disem- 

 bogue themselves into Algoa Bay, 



t A line of territory situated between the villages of Uitenhage and 

 Graafl-Reiaet. 



