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THE ORANITE AEEA OF THE SCHAPENBERG, 
SOMERSET WEST. 
(From the Geological Department, South African College.) 
By a. E. E. Walker. 
(With Map; text-fig. 1.) 
1. Introduction. 
The following paper is the outcome of work undertaken on the 
suggestion of Dr. Rogers, Acting Director of the Geological Survey of the 
Union of South Africa, who, at the time the subject was mooted, kindly 
lent me the specimens which he had previously collected in the area, 
together with thin sections he had had prepared of several of them, for 
purposes of description. I wish to record my indebtedness to him for his 
kindness. So far as I am aware, the first — and only — published description 
of the granite of this area is a short paragraph occurring on p. 42 of the 
first edition of Dr. Rogers' " Geology of Cape Colony." * 
To avoid confusion, the name Scliapenberg is assumed, in this paper, 
to denote the whole of the rudely dome-shaped mountainous area occurring 
immediately to the east of Somerset West and north of the main road 
to Caledon. 
On this assumption it includes metamorphosed sediments of the 
Malmesbury Series as well as rocks of igneous origin. The metamorphosed 
sediments form the high ground along the north-eastern side, and, in part, 
on the west, whilst grrauite constitutes the remainder. The Schapenberg 
thus defined rises steeply on the west, south and east — less steeply on the 
north and north-east — to a height of about 800 ft. above sea-level. 
Streams rising in the central portion have eroded steep- sided ravines, 
thereby giving rise to mountainous spurs semi-detached from the central 
mass. On the south-western side there is the Water Kloof stream flowing 
in a south-westerly direction and dividing the two largest of such spurs. 
Another stream operating also in a south-westerly direction, and assisted 
* This paragraph has been retained in the second edition of " Geology of Cape 
Colony/' by Drs. A. W. Rogers and A. L. du Toit ; see p. 32. 
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