Of the Vicinity of the Cape of Good Hope. 233 



however does not always pervade the entire piece, which is some- 

 times white or grey in part, and red in part.] 



4. These fragments of granite, containing black tourmalines, are 

 to be seen in large quantities between the Lion's Head and Table 

 Mountain. Very large fragments are often imbedded, in the sand- 

 stone, presenting a very chequered appearance. 



5. Rocks in the vicinity, a dark slate and slaty clay. 



6. Rocks from the top of a range of mountains, (sandstone like 

 Table Mountain,) forty or fifty miles east of Cape Town. [These 

 rocks have much of the character of grauwacke; pebbles and frag- 

 ments of quartz are imbedded in an exceedingly firm siliceous ce- 

 ment, through the whole of which small angular fragments are dis- 

 persed.] 



7. Granite from the mountain, called Paarl Berg, pretty well 

 described in Barrow. On the top of it are two immense blocks of 

 granite, supposed to be the largest in the world. One of them is at 

 least a mile in circumference, and five or six hundred feet high. As 

 you approach them you feel a sensation of awe, somewhat as if 

 drawing near a mighty mausoleum of the dead. [This granite con- 

 sists of white feldspar, grey quartz and black mica ; the feldspar is 

 partially decomposed, and in some portions pulverulent.] 



8. Is a specimen of the seams of harder rock, with which they 

 are intersected. The Paarl Berg is a mountain eight or ten miles 

 long, and perhaps one thousand three hundred feet high. I have 

 seen no granite any where like that of the Paarl Berg. The moun- 

 tains in the vicinity are certainly all of sandstone. The rock, called 

 the Diamond, appears as if it had been broken by an earthquake. 

 [This is a granitic compound, but without mica; very small granu- 

 lar quartz is intimately blended with a feldspar, which is almost 

 compact.] 



9. Blue asbestos, given me by some friends at Tullagh, eighty 

 or ninety miles north-east from this, said to be from a place called 

 Roggeveld, (Rye field,) an elevated country still on beyond, anf; 

 above them. As you are aware, the country ascends by successive 

 terraces, till you reach the vast plateau or Karroo of the Orange 

 River, called the Great Karroo — Roggeveld Karroo is an intern)edi- 

 ate one between this, and the Great Karroo. [This is very beauti- 

 ful asbestos ; the color is sky blue, and the fibres are as fine as the 

 most delicate silk: it is in regular veins, which evidently ran cross- 

 wise between walls of rock, exhibiting smooth joining surfaces, 



Vol. XXIX.— No. 2. 30 



