462 mr. w. h. penning on the 



Discussion. 



Mr. GiPsoN maintained that the thickness of the AYitwatersrand 

 beds, which was stated by the Author to be 17,000 feet, could not 

 be determined, the strata being so greatly faulted and so similar in 

 composition that a complete sequence could not be obtained. So far 

 as he knew them, the rocks mentioned as granite in the paper 

 were schists, gneisses, some granites, and various other highly 

 altered crystalline rocks. The Witwatersrand beds appeared to 

 have been thrust over these crystalline rocks. He considered the 

 Author's view that the coal-bearing rocks had covered so wide an 

 area to be doubtful. 



Mr. Alfoed thought the geological section exhibited fairly correct, 

 but where it showed the De-Kaap Yaliey as a denuded anticlinal it 

 was certainly open to question. There were very evident signs of 

 folding in the beds of the Makongwa Mountains, which lie to the 

 south-east of the De-Kaap Yaliey ; also farther north, across the 

 Crocodile Eiver. He could not think that sufficient evidence had yet 

 been met with to justify the use of the names of geological systems 

 such as Oolitic, Devonian, and Silurian. He had seen the "corals " 

 alluded to, and very much doubted that they were corals at all. 

 They occur in a bed of steatite which comes in between the granite 

 and the schists of the Makongwa Mountains, and they are ex- 

 ceedingly obscure. Excepting only a few coal fossils, no organic 

 remains had to his knowledge as yet been discovered in the TransvaaL 

 The fossil fishes, of which a photograph was shown, come from the 

 Ladybrand District, in the south-eastern part of the Orange Free 

 State, and are not in any way connected with the Coal-formation. 

 There are some good specimens of these in the Bloemfontein 

 Museum. 



The sandstones, quartzites, siliceous schists, and conglomerates of 

 the Witwatersrand form a vast series of rocks which are recognizable 

 under varied conditions over almost the whole of the Transvaal. 

 It appears, therefore, curious to bracket them with the small local 

 beds of the Klip Eiver, which are probably only the denuded and 

 altered remains of the same, and to give the whole the name of a 

 small range of hills such as the Megaliesberg. It remains to be seen 

 how far the series may be capable of subdivision. The Black Eeef 

 is a small and very local series of highly ferruginous deposits, which 

 have become notable on account of some parts of it having been 

 found auriferous. The difference of dip in the rocks of the Wit- 

 watersrand is interesting, and more so when noticed in relation to 

 the gold-bearing value of the beds. 



Prof. Rupert Jones congratulated the Society on the accumulating 

 knowledge of South-African geology, although the several published 

 accounts of observations are imperfect and more or less contradictory. 

 The Author's section, though apparently generalized in character, 

 evidently contains distinct information on some points in the geo- 

 logical structure of the region concerned. Prom what the speaker 

 had gathered from his friends, the rocks in the Transvaal are much 



