PRE-CAPE ROCKS OF SOUTH AND WEST OF COLONY 35 



of the rocks to be clear areas in a finely crystalline 

 quartzose ground mass containing biotite. These clear 

 spots are composed of very minute crystalline grains of 

 a faintly greenish tinted mineral, which is probably 

 cordierite. Small felspars, recognisable by their twin- 

 ning, have been developed along with muscovite close to 

 the actual contact. 



The inclusions of slate in the body of the granite be- 

 come more and more metamorphosed as the distance 

 from the junction increases, ultimately forming dark 

 coloured patches which are rich in biotite ; they some- 

 times contain cordierite and garnet, and retain no trace of 

 clastic structure. Along the Victoria Road between Sea 

 Point and Clifton a huge inclusion of slate has been all 

 but absorbed by the granite, and has been altered into 

 a banded gneissic rock, which shades off into the en- 

 veloping granite. 



In several places east of the Darling granite, and in 

 the George district, the slates become highly micaceous 

 near the contact and pass into typical mica-schists, 

 quartzose rocks which glisten owing to the innumerable 

 flakes of pale mica arranged parallel to one another. 



At Zwart Kiver Bridge in George there is a magni- 

 ficent section of andalusite schist, 1 a rock composed of 

 andalusite, mica and quartz ; the crystals of andalusite 

 are often over two inches long. The schist occurs 

 within five yards of a remarkably coarse muscovite- 

 biotite granite dyke, which also contains tourmaline. 



On Klip Drift Extension in Van Khyn's Dorp 2 some 



1 Schwarz, Bee. Albany Museum, ii., p. 164, 1907. 

 2 G. C.,ix., p. 17. 



3* 



