TERTIARY AND RECENT DEPOSITS 401 



was entirely in these limestones, and failed to reach the 

 underlying formation. 



These old dunes were formed at a time when the 

 coast was at a lower level than now, during the period 

 represented by raised beaches in several parts of the 

 Colony. 



The dune limestones are in places rather easily dis- 

 integrated, and weather very unequally, hence shallow 

 caves are of frequent occurrence in them. At Cape In- 

 fanta there is a fairly large cave with a small entrance 

 on the cliff; the roof is hung with stalactites, long 

 tapering tubes of calcite deposited from the water per- 

 colating through the overlying limestone, and the floor 

 is formed by a mixture of sand and bat-guano. The 

 origin of the cave was probably due to a stream that no 

 longer exists. This cavern is perhaps the largest (some 

 150 feet long and 20 feet high in parts) yet found in the 

 dune limestones. Other caves of considerable depth, 

 such as the Kellers near Danger Point, have streams of 

 water still flowing through them. 



7. LIMESTONES OF THE INTERIOE. 



On the coast side of the Langebergen there is fre- 

 quently a thin layer of whitish impure limestone imme- 

 diately below the soil, and a similar rock covers wide 

 areas in the western portion of Malmesbury and Piquet- 

 berg. The calcareous layer is especially well developed 

 between the Kaffir Kuil's and Gouritz Rivers in Rivers- 

 dale. There is a particular variety of the limestone seen 

 in the soil about a foot below the surface that is now in 



process of formation. This is a nodular rock, rather 



26 



