on the Geological Phenomena near Cape Town. 533 



most numerous adjacent to it. Veins of granite are likewise visible 

 on the shore, intersecting the gneiss near the junction of the two 

 formations ; and numerous instances of the entanglement of the 

 granite and gneiss were noticed by the author, the fragments of the 

 latter, inclosed in the former, being almost invariably coated by 

 quartz. It is also stated, that veins of quartz traverse the entangled 

 portions exactly in the same manner as the solid mass of gneiss ; 

 and that the entanglement is nearly always in connexion with the 

 joints, pointing out, Mr. Clarke is of opinion, that all these pheno- 

 mena are due to one cause ; and he is further of opinion, that the si- 

 lica in the quartz veins was deposited from a state of vapour. The 

 granite is generally large-grained ; but where it forms veins, either in 

 the gneiss or in the great mass of granite, it becomes finely grained. 



The whole of the shore from this point is granitic, as well as the 

 Lion's Hill, except the cap of sandstone. The junction of the granite 

 and the gneiss cannot be satisfactorily traced owing to the covering of 

 vegetation, but the granite is flanked by nearly vertical or upturned 

 beds of gneiss and slate, and is capped by horizontal beds of sand- 

 stone, which are penetrated by granite veins. These phenomena, 

 Mr. Clarke states, clearly establish the induction, that though the 

 periods may have been distant, the schistose rocks owe their elevation 

 to the up-burst of the granite before the deposition of the sandstone ; 

 and that subsequently the granite has been re-heated and further 

 elevated, carrying with it the whole area described to a higher level. 



3. Camp's Bay and Cobler's Hole. — Granite extends along the 

 shore and around Camp's Bay, lining the edge of the sea with huge 

 rounded blocks, and the masses in situ are traversed by deep fissures. 

 Near the cottages situated on the road which winds round the mid- 

 dle portion of the Lion's Head and passes over the Kloof to Cape 

 Town, two trap dykes intersect a soft decomposed granite. Under 

 the Lion's Head at Cobler's Hole, and 400 feet above the level of the 

 sea, the granite ledges, for a vertical height of 1 or 12 feet and 30 

 yards in horizontal extent, are stated to be covered with shingly soil or 

 an elevated beach, having imbedded shells of the same species as now 

 inhabit the neighbouring ocean ; and they are so firmly fixed in the 

 soil or to the granite pebbles, as to require some trouble to extract 

 them entire. 



4. The Kloof. — A vein of trap near the summit of the pass tra- 

 verses the granite, which is there also in a state of decomposition. 

 About six feet above the road, the dyke is interrupted by a horizon- 

 tal shift of eighteen inches to the west. At the Kloof is another 

 dyke, which is described in Dr. Abel's work*. 



5. Table Mountain. — The eastern side of this mountain is formed 

 of granite for nearly two-thirds of its vertical height. On the flat 

 ground at Wynberg occur large blocks of granite perfectly rounded, 

 and the granite floor has the same smooth and rounded surface. 

 The flat between Wynberg and Constantia has also a substratum of 

 granite, with a covering of blown sand or vegetable soil. 



* Narrative of a Journey in the Interior of China, &c, 1818. 



