GEOLOGY OF THE NEIGHBOURHOOD OF STELLEN 150SC H. I35 



sional beds of hard brown quartzite, and here and there banded 

 cherty layers. The sandstones show distinct false-bedding and 

 split easily alonjr the main bedding-planes, and two sets of ver- 

 tical joints. Further towards Eerste River Station the outcrops 

 are of hard blue hornfels. without prominent bedding or joints, 

 with chiastolite s{X)ts which are most readily seen on cross frac- 

 tures. There are no beds in the whole succession that are really 

 entitled to be called slate, and few that are unequivocally sand- 

 stone, and the original deposit seems to have consisted of sandy 

 clays and fine clayey sandstones without any coarser deposits 

 whatever 



Similar facies of the A'lalmesbury rocks can be seen on the 

 Stellenbosch side of the granite mass. The blue s})otted horn- 

 fels appears in the river bed on the south-east side of Papegaais- 

 berg. The brown, spotted sandstones are seen in jxior exposures 

 here and there on the top of the Papegaaisberg ridge, and on the 

 northern slopes of Stellenbosch Mountain. Spotted rocks, whicli 

 we may call slates, although they lack true slaty cleavage, appear 

 in the kloofs on the west side of Stellenbosch Mountain, and 

 boulders of spotted hornfels and sandstone (>ccur generally along 

 all the contact zones and help one to trace these on the surface. 

 The dip of the beds, where they can be seen in place, is always 

 more than 60°, and the strike is roughly parallel to the eastern 

 margin of the series as laid down on the accompanying geological 

 map (Plate 5). 



The tourmalinized rocks of the contact zones liave already 

 been mentioned. It is not quite clear whether they belong to 

 the Malmesbury series or are to be regarded as the altered 

 margin of the granite itself. 



The French Hoek Series. 



The winding road which climbs from the Flats up to Hels 

 Hoogte begins and finishes its ascent in granite, but on the way 

 it cuts through a series of very decomposed and crushed sedi- 

 mentary rocks, which strike about 10° west of magnetic north. 

 These rocks, as well as the granite for some distance on either 

 side of them, have been caught and crushed in the zone of the 

 Jonker's Hoek Fault. For the greater part the rocks are slates 

 or phyllites, and they possess a well-developed cleavage, which 

 coincides with the stratification. Some beds, however, are 

 sheared grits or arkoses, and there is at least one band of greatly 

 crushed conglomerate with elongated and flattened pebbles. On 

 the hill tops north of the Hels Hoogte road, and again on the 

 top of the Schoongezicht ridge, conglomerates and grits reappear, 

 and they are well exposed in a deep kloof on the farm Onrust, 

 and again on Knor Hoek. The pebbles are often several inches 

 in diameter, and some have been flattened into discs, while others 

 have been elongated. Slicing these for the microscope gives one' 

 little assistance in identifying the pebbles, because the material 

 is crowded with decomj)osition-products. Some of the pebbles, 



