SOUTHERN AFRICA. 35 
convulfion of the earth has happened in this part of Africa fuf- 
ficient to have difturbed the nice arrangement of its parts. The 
ftrata of thefe poftdeluvian ruins, not being placed in the order 
of their fpecific gravity, might lead to the conclufion that they 
were depofited in fucceffive periods of time, were it not for the 
circumftance of their lying clofe upon each other without any 
intermediate veins of earthy or other extraneous materials. 
The ftratification of the Cape peninfula, and indeed of the whole 
colony, is arranged in the following order : 
The fhores of Table Bay, and the fubftratum of the plain on 
which the town is built, compofe a bed of a blue compadl 
fchiftus, generally placed in parallel ridges in the diredion of 
north-weft and fouth-eaft, but frequently interrupted by large 
maffes of a hard flinty rock of the fame color, belonging to that 
clafs of aggregated ftones propofed by Mr. Kirwan to be called 
granitelles. Fine blue flags, with whitifli ftreaks, are procured 
from Robben Ifland, in the mouth of Table Bay, which are ufed 
for fteps, and for paving the terraces in front of moft of the 
houfes. 
Upon the fchiftus lies a body of ftrong clay colored with 
iron from a pale yellow to deep red, and abounding with 
brown foliated mica. Embedded in the clay are immenfe 
blocks of granite fo loofely cemented together that the con- 
ftituent parts are eafily feparable by the hand. The mica, the 
fand, and indeed the whole bed of clay, feem to have been 
formed from the decompofition of the granite. Between the 
Lion's Head and the fea are vaft mafles of thefe aggregated 
F 2 ftones 
