GEOLOGY OF THE NEIGHBOURHOOD OF STELLEN BOSCH. 1 25 



certain of these formations on the map are only approximately 

 correct. 



Before proceeding to describe these geological formations in 

 greater detail, it will be desirable to refer to 



The Physiographic Features of the District. 



Stellenbosch lies in the narrow belt of foothills which fringe 

 the western escarpment of the Drakenstein Mountains, and 

 which, gradually dying out towards the west, merge into the 

 Coastal Plain or Cape Flats (see map, Plate 4). To the east 

 of us lies the almost sheer wall of the Drakenstein, with its pro- 

 jecting spurs to which we give the names of the Ban Hoek 

 Mountains and the Stellenbosch Mountains, and its island-like 

 outliers Simonsberg (to the north-east) and Helderberg (to the 

 south), which are just the detached ends of similat spurs. The 

 average height of these mountains is well over 3,000 feet, and 

 the following are the heights of some of the more prominent 

 peaks : — 



Stellenbosch Mountains (trigonometrical beacon), 3,824 ft. 



Sneeuw Kop (trigonometrical beacon), 5.21 1 ft. 



Bootman's Kop, 2,965 ft. 



Twin Peaks, Ban Hoek Range, 5,160 ft. 



Helderberg (trigonometrical beacon), 3,724 ft. 



Simonsberg, summit, 4.770 ft. 



Simonsberg, Kanon Kop (trigonometrical beacon), 2,994ft. 



Between the spurs the valleys are narrow and deeply incised. 

 The most noteworthy of them are French Hoek and Ban Hoek, 

 which open out at Draken.stein into the flat-bottomed valley of 

 the Berg River, and Jonker's Hoek, which debouches into the 

 Stellenbosch Valley. Between the valleys of Drakenstein and 

 Stellenbosch the high neck, known as Hels Hoogte. connects 

 Simonsberg with the Ban Hoek Mountains, and forms a divide 

 between the Berg River System, a branch of which, the Dwars 

 River, rises in Ban Hoek, and the Eerste River System. The 

 valleys among the foothills have gentler slopes than those in the 

 hard Table Mountain Sandstone. The largest of them are Ida's 

 Valley, north-east of Stellenbosch, and the valley of the Planken- 

 berg River to the north-west. Between these valleys is the long 

 ridge, which forms the northern boundary of the Stellenbosch 

 Flats; this ridge does not seem to possess any local name, and 

 we mav call it the Schoongezicht Ridge, from Mr. Merriman's 

 beautiful farm, which is l)C)unded by it. The wide, flat valley of 

 . the I'lankenberg River runs in a north-westerly direction to 

 Elsenburg, and is delimited by the Schoongezicht Ridge on one 

 hand, and by the Papegaaisberg Ridge, running from Papegaais- 

 berg up to Bottelary Hill, on the other hand. 



The Stellenbosch X'alley, bounded on the south by Stellen- 

 bosch Mountain, on the east by Hels Hoogte, on the north by 

 the Schoongezicht Ridge, and on the west by the Papegaaisberg 

 Ridge, is shaped something Hke a starfish. One long arm of the 



