SOUTHERN AFRICx\, 45 
inasses of a bard flinty rock of the same color, belonging to 
that class of aggregated stones proposed by Mr. Kirwan to 
be called granitelles. Fine blue flags, with whitish streaks, 
are procured from Robben Island, in the mouth of Table Bay, 
which are used for steps, and for paving the terraces in front 
of most of the houses. 
Upon the Schistus lies a body of strong clay colored with 
iron from a pale yellow to deep red, and abounding with 
brown foliated mica. Embedded in the clay are immense 
blocks of granite, the component parts of which are so loosely 
cemented together as easily to be separated by the hand. The 
mica, the sand, and indeed the whole bed of clay, seem to have 
been formed from the decomposition of the granite. Be- 
tween the Lion's Head and the sea are vast masses of these 
aggregated stones entirely exposed. Most of them are rent 
and^ falling asunder by their own weight : others are com- 
pletely hollowed out so as to be nothing more than a crust or 
shell ; and they have almost invariably a small aperture on 
that side of the stone which faces the bottom of the hill or 
the sea-shore. Such excavated blocks of coarse granite are 
very common on the hills of Africa, and are frequently in- 
habited by runaway slaves. 
Resting on the granite and clay is the first horizontal stra- 
tum of the Table Mountain, commencing at about five hun- 
dred feet above the level of the sea. It is siliceous sand-stone 
of a dirty yellow color. Above this is a deep brown sand- 
stone, containing calciform ores of iron, and veins of hematite 
G 2 
