Dr. C. Sandberg — The Tygerherg Recumbent Fold. 313 



North-east of the Tygerherg farm-homestead the Dwyka and Lower 

 Ecca Series stand nearly vertical ; east and west along their strike 

 (parallel to and north of the Tygerherg) they hecome more and more 

 inclined, and finally ahout 6 miles to the east and 4 miles to the west 

 they are lying nearly flat. Some five hundred yards south-west of 

 this farmhouse (and due south of where the Upper Dwyka and Ecca 

 Series are still inclined close on to the vertical) the Shales (Upper 

 Dwyka or Lower Ecca) can he seen, right down at the hottom of the 

 river, to dip towards the main range (south) and under the Dwyka 

 conglomerate. These shales are lying very near the horizontal. 



To the south of the range the Dwyka and Ecca Series are lying 

 practically horizontal, carrying numerous fragments of Witteberg 

 quartzites in situ. North and south of the central part of the 

 Tygerherg range the Dwyka and Ecca Series are consistently lying 

 asymmetrical, namely, nearly horizontal to the south and nearly vertical 

 to the north of the AVitteberg quartzites, after the way illustrated in 

 my sections.^ I fail to see how this behaviour of the strata is 

 reconcilable with the squeezed-lead-vice theory. 



Going over to the larger mass of Witteberg Beds, south of the 

 Tygerherg, facing the Zwartebergen, we again find fragments 

 (lambeaux) of Witteberg quartzites lying in such positions to the 

 north of the main range as to clearly point to an overfold. When, 

 therefore, Professor Schwarz declares- that " the difiiculty which the 

 Tygerherg presents is that although the quartzites tower up in a narrow 

 vertical anticline, the Dwyka shales and conglomerate around it 

 are only moderately inclined, and indeed in some places lie actually 

 flat," the question, for the mere pleasure of being able to put it into 

 a nutshell, is so disfigured and cut down as to render it entirely 

 unrecognisable. 



Finally, I fail to understand either the strength or the meaning of 

 the argument that " there is no break in the succession [of the beds 

 in the larger mass of Witteberg Beds fronting the Zwartebergen] 

 whence the root of the supposed overfold could have originated." 

 Professor Schwarz surely does not mean to convey the impression that 

 the Witteberg Beds here form a closed anticlinal. He knows the 

 region too well to make a statement which is in actual contradiction 

 to the evidence in the field. 



Summarising, we must conclude that in and near the Tygerherg 

 range the mutual relations {lagenmgs Verhdltnisse) betw.een the Dwyka- 

 Ecca Series and Witteberg quartzites are in contradiction to the 

 squeezed-lead or mushroom-fold theory ; they are, on the other hand, 

 in harmony with the occurrence of a recumbent fold ; therefore, even 

 at the risk of endangering the present conception of the structure of 

 the coast-ranges, I must adhere to the latter explanation of the 

 Tygerherg phenomena until more serious contradictory evidence is 

 forthcoming. 



^ Trans. Geol. Soc. South Africa, loc. cit. 

 '^ Geol. Mag., loc. cit. 



