Notes on the Becent Limestones of Cape Colony. 433 



conglomerate probably represents a beach. Other conglomerates 

 are met with at the base of the limestone near Uilenkraal Eiver and 

 Strays Point. 



A few large marine shells, such as the oyster, were found in the 

 limestone of Honing Rug, and we were informed that a bed contain- 

 ing such shells was to be seen in a ravine in the Bredasdorp range, 

 although we did not come across it. The presence of a few large 

 marine shells is not in itself good evidence for any one mode of 

 origin of a recent deposit, for man may have carried them to the 

 spot where they are found. 



From all the evidence, however, at present obtained one is led 

 to conclude that the limestone hills were once sand-dunes near the 

 shore, and that they have been raised relatively to the sea-level 

 together with the rock they rest on. The amount of elevation is not 

 known exactly, but it is probably between 50 ft. and 100 ft. The 

 elevation did not take place all at once, but extended throughout 

 a considerable lapse of time, and was almost certainly interrupted 

 by periods of subsidence. A study of the limestone along the coast 

 seems to prove this, for at Waagen-huis Krantz, and north of the 

 Kellers by Danger Point, the limestone which has certainly been 

 formed on land is seen exposed beneath low-water mark, and can 

 only have reached its present level by a relative sinking of the land. 

 Evidence of the same nature is also obtainable at Saldanha Bay. 



The mammalian bones, known to us from the limestone or 

 associated sand, up to the present time have been briefly examined 

 by Messrs. Sclater and Peringuey, who consider that they all belong 

 to living species, although some of them no longer live in the 

 districts where the bones were found. Mr. Lightfoot named a 

 collection of snail shells from the Saldanha Bay limestone, and 

 found that they all belonged to species living in that district. 



The localities where we obtained bones are Hoetjes Bay and 

 Linkerhand's Gat near Stanford, but they must occur at many other 

 places. Mr. Thwaites, the R.M. of Bredasdorp, gave the Museum 

 some fine specimens from the sand-dunes of Struys Bay, including 

 skulls of a rhinoceros and hartebeest, and an elephant's jaw. 



There are some interesting caves in the limestone (fig. 2). Many 

 small ones have been formed by the action of the weather and waves 

 along the coast. In the ravines cut through the Downs caves of 

 all sizes are formed by the weathering of soft rock underlying a 

 harder layer. These sometimes contain deposits of guano due to 

 bats and rock rabbits, which would be very valuable were it not for 

 the difficulty of access. 



