( S83 ) 
X. — On the Geognosy of the Cape of Good Hope. By 
Professor Jameson. 
The peninsula of the Cape of Good Hope is a mountainous 
ridge, stretching nearly north and south for thirty or forty 
miles, and connected on the east side, and near its northern ex- 
tremity, with the main body of Africa, by a flat sandy isthmus, 
about ten miles broad, having Table Bay on the north of it, 
and False Bay on the south. The southern extremity of this 
peninsula, extending into the sea, Avith False Bay on the east, 
and the ocean on the south and west, is properly the Cape of 
Good Hope, and is the most southern point of Africa* At this 
point, the chain of mountains which forms the peninsula, though 
rugged, is lower than at the north end, where it is terminated 
by Table Mountain and two others, which form an amphi- 
theatre overlooking Table Bay, and opening to the north. 
The mountains of the ridge extending from the Cape to the ter- 
mination of the peninsula on the north, vary in shape ; but the 
most frequent forms incline more or less to sharp conical* The 
three mountains which terminate the peninsula on the north, 
are, the Table Mountain in the middle ; the Lion’s Head, some- 
times called the Sugar Loaf, on the west side ; and the Devil’s 
Peak on the east. The Lion’s Head, which is about 2100 feet 
above the level of the sea, is separated from the Table Moun- 
tain by a valley, that descends to the depth of 1500 or 2000 
feet below the summit of the Table Mountain, which is itself 
3582 above the level of the sea. On the west of the Lion’s 
Head, there is a lower eminencej named the Lion’s Pump, from 
which the ground declines gradually to the sea. The amphi- 
theatre, formed by these three mountains, is about five or 
six miles in diameter, in the centre of which is placed Cape 
Town '' 
The rocks of which the peninsula is composed are few in 
number, and of simple structure. They are granite, gneiss, 
day-slate, sandstone, and greenstone. Of these the most abun- 
* Transactions of the Royal Society of Edinburgh, vol. vii. p. 271. 
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