NOTES ON THE EECENT LIMESTONES ON PAETS OF 

 THE SOUTH AND WEST COASTS OF CAPE COLONY. 



By A. W. Rogers and E. H. L. Schwarz. 



(Read June 29, 1898.) 



With Plate X. 



Round the west and south coasts of the Colony, from St. Helena 

 Bay to the mouth of the Breede River, there are more or less 

 extensive deposits of a sandy limestone. It is the purpose of this 

 paper to describe the rock found within these limits, excluding that 

 of parts of the shores of Table and False Bays. 



These rocks have not had much attention paid them by previous 

 observers. They are mentioned by Clarke * and Green, f but the 

 only accounts of them we have noticed are those by Andrew Bain J 

 and Hochstetter ; Bain recorded one of their chief characters, that 

 they contain large numbers of a common land snail. 



Hochstetter § described the limestones of the Peninsula and 

 Robben Island, and came to the conclusion that they were formed 

 by carbonate of lime cementing together debris piled up by wind and 

 waves. 



Dunn |i put them in at one or two localities on his maps as 

 Tertiary beds. 



It is only on steep shores which drop suddenly into fairly deep 

 water that little or no calcareous rock is found. The chief instance 

 of this is the coast between Gordon's Bay and Kogel Bay, where 

 the Table Mountain sandstone forms a steep foreshore. 



The rock is made up of grains of sand imbedded in a calcareous 

 matrix. Sometimes there are numerous fragments of marine shells, 

 including some whole ones, but these are rare. It is impossible to 



* Clarke, Proc. Geol. Soc, Lond., iii., p. 418. 

 f Green, A. H., Quart. Journ., Geol. Soc., Lond., xliv., p. 239. 

 J Bain, A. G., Trans. Geol. Soc, Lond., ser. 2, vol. vii., part iv., p. 175. 

 § v. Hochstetter, Reise der Oster., Frig., Novara urn die Erde. Geol. Theil., 

 p. 19. Vienna, 1886. 



|| Dunn, E. J., Geological Sketch Map of S. Africa, 1887 and an earlier edition. 



427 



