Br. C. Sandberg — The Tygerherg Recumbent Fold. 311 



Y. — The Tygeebeeg Eec0mbent Fold. 

 By Dr. C. Sandberg, Arnhem, Holland, 



APTEE a prolonged and very careful study of the region on the 

 spot as well as from existing literature, I summarised my 

 observations and conclusions, in 1906, in a paper on the interesting 

 and peculiar formation of the Tygerberg range in the Cape Colony.^ 



Fig. 1. — Reproduction of photograph of the western side of the Tygerb'erg-poort 

 (=gap), Tygerberg range, Cape Colony. (The dotted line A corre- 

 sponds with the dotted line A in the diagram, Fig. 2.) 



The first question to be decided here is : Can vpe explain the 

 peculiar mutual stratigraphical relations between the Witteberg 

 quartzites and the Lower Dwj^ka and Ecca Series and their tectonic 

 behaviour by assuming that this range represents a squeezed-up 

 anticlinal fold ? A second question might naturally follow, viz. : 

 How are we to explain the occurrence of this range should field 

 evidence be in contradiction with the above assumption ? It would 

 seem that Professor E. H. L. Schwarz presumes to settle this intricate 

 geological problem by the simple exhibition of a single photograph ^ and 

 the reference to another one,^ in favour of his ' squeezed-lead ' theory. 

 To these I may be allowed to oppose my photograph (Fig. 1 ) of the 

 western side of the Tygerberg-poort ( = gap) and my ideal section 

 (Fig. 2), the north corner of which is simply a copy of the behaviour 

 of the strata as reproduced on the above-mentioned photograph. 



Another photograph taken by me some two hundred yards to the 

 north of the Tygerberg range represents a small ' lambeau ' of 

 "Witteberg quartzites in situ (Fig. 3). This 'lambeau,' whilst reposing 

 on Lower Dwyka, is separated from the "Witteberg quartzite range 



1 See Trans. Geol. Soc. South Africa, vol. ix, 1906, pp. 82-89, pi. xsi. 



2 Geol. Mag., Dec. V, Vol. IV, 1907, No. XI, p. 487, PL XXII. 



^ Loc. cit., p. 489, and Geol. of Cape Colony, by A. W. Sogers, 1905, p. 141. 



