6 Transactions of the South African Philosophical Society. 



jointed than those of a roughly spherical form, and that the joints 

 traversed the pebbles approximately at right angles to their longer 

 axes in whatever positions the pebbles lay in the matrix. 



In order to get some idea as to the conditions that prevailed 

 during the formation of the Pakhuis conglomerate we must briefly 

 recall the nature and distribution of the group of which it forms 

 quite a subordinate part. The Table Mountain series consists 

 chiefly of rather coarse sandstone, usually strongly false-bedded, 

 and it contains many isolated water- worn pebbles of quartz distri- 

 buted irregularly through the greater part of the sandstone. Occa- 

 sionally, the pebbles occur together in layers one pebble thick ; much 

 more rarely they are sufficiently abundant to warrant the rock being 

 called a conglomerate ; in such cases, as at Pikenier's Kloof, Baboon 

 Point, and a few other places in the Western districts, slates, sand- 

 stones, granite, and jasper are met with in the form of pebbles in 

 addition to the usual vein-quartz. Argillaceous beds form but a 

 very small proportion of the whole series : there is one group of 

 them near the top, the shale-band to which the Pakhuis conglo- 

 merate belongs, and which has been followed through a distance of 

 some 300 miles round the Colony, and there are irregularly-developed 

 bands of red shale near the base of the formation. The whole 

 thickness of the series is about 5,000 feet, of which probably not 

 more than a twelfth is noticeably argillaceous. Current-bedding and 

 ripple-marks can generally be found throughout the group, and sun- 

 cracked surfaces have been seen in some of the red shaly beds near 

 the base, so it is evident that the formation was deposited in 

 shallow water, and at places parts of the area were laid bare for a 

 short time before fresh sediment buried the dry surface of previously 

 deposited mud. Although the whole region occupied by the forma- 

 tion between the Bokkeveld Mountain in Calvinia and the Umta- 

 mvuna river, where it passes into Natal, has not been carefully 

 examined, the above description probably applies everywhere within 

 those limits. The area in which the formation can be seen, or can 

 be legitimately assumed to exist under the present surface, is at 

 least 80,000 square miles in extent. No organic remains, except 

 some obscure tracks or worm-castings, have as yet been found in the 

 series ; and the rocks are now sufficiently well known to allow one to 

 hold that there are no important bands containing marine fossils. 

 These facts most certainly negative the idea that the Table Mountain 

 series was laid down under the sea, and it is difficult to reconcile the 

 supposition of a lacustrine origin with the wide distribution of so 

 much coarse sand, for in the tranquil water of a lake the coarse 

 material brought into it by rivers is not spread over the whole area 



