Geological Society of London. 189 



fission is due to the same cause. It was also suggested that the 

 development of the crystals may in some cases account for this strain, 

 while in other instances similar evidence of strain is seen in perlitic 

 areas where no crystal is visible. Other details concerning perlitic 

 and spherulitic structure were also discussed. 



3. " Sketches of South- African Geology. No. 1. A Sketch of the 

 High-level Coal-field of South Africa." By W. H. Penning, Esq., 

 F.G.S. 



In this paper the author gave a sketch of the High-level Coal-field 

 of the Transvaal and the neighbouring region. This Coal-field was 

 described as extending 400 miles from north to south, with an 

 average breadth of 140 miles, so that its area is about 56,000 square 

 miles. The tract consists of an elevated plateau forming the " High 

 Veldts " of the Transvaal and the plains of the Orange Free State. 

 It slopes away to the north-west, and is scarped to the south and east 

 by the heights known as the Stormberg and Drakensberg mountains ; 

 nearly all the principal rivers of South Africa take their rise in this 

 tract of land. The coal-bearing beds forming the plateau rest un- 

 conformably in the north upon deposits probably of Upper Palasozoic 

 age, described as the Megaliesberg beds. In the south-west the 

 Lower Karoo beds underlie the coal-beds, also unconformably. The 

 beds of the high grounds consist above of sandstones, called the 

 " High Veldt beds " by the author, and below of shales, for which 

 the name of " Kimberley beds " is proposed, after the chief town of 

 Griqualand West, in which district they form nearly the whole surface. 

 These two series are conformable, and generally lie horizontally. In 

 the shales coal occurs only in minute patches ; the seams of coal are 

 interstratified with the sandstones, into which the shales pass up 

 gradually, and which sometimes include thick-bedded grits and con- 

 glomerates. Both shales and sandstones contain interstratifications 

 and numerous dykes of trap, which have rarely produced much 

 alteration in the sedimentary beds, fi'om which the author concludes 

 that the eruptions were subaqueous and contemporaneous or nearly 

 so. Owing to the persistent horizontality of the rocks, the moun- 

 tains and valleys are merely carved out of the plateau, so that the 

 thickness of the deposits is easily measured. The author gave 2300 

 feet as the minimum thickness of each series. By a comparative 

 section it was shown that the coal-bearing sandstones ("High Veldt 

 beds ") are the " Upper Karoo " of Stow, and the " Stormberg beds " 

 of Dunn. The " Kimberley beds " are the Upper Karoo beds of 

 Dunn. 



In the latter part of his paper the author noticed brieflj^ the 

 different localities where coal has been found, namely, Newcastle. 

 Lange's Nek, the Lebelelasberg mountains, near New Scotland, 

 several places on the High Veldt, Wemburg, Brand foote, Cornet 

 Spruit, Burgersdorf, and Indwe, twenty miles east of Dordrecht. 

 The most northerly point of the Transvaal where coal has been found 

 is on the Letsebo river. "West of the Drakensberg coal occurs at 

 a lower level. 



