552 MR. D. DRAPER ON THE GEOLOGT [Nov. 1 894, 



quartz-pebbles about the size of pigeons' eggs. The dark colour of 

 the rock is caused by the •quantity of manganese oxide, which occurs 

 in small veins and beds in the rock, and generally completely 

 envelopes the quartz-pebbles. 



Silicified remains of trees are abundant in the upper portion of 

 the Red Beds and in the dark-coloured grit. 1 In many cases the 

 lower portion of the trunk is found standing erect, on the spot 

 where the tree originally grew. Some of these trees were of con- 

 siderable size, judging from their silicified remains, which measure 

 over 4 feet in diameter in occasional specimens. 



(4) Molteno Beds. 



This extremely important series occupies a large area in South- 

 eastern Africa. 



The High-veld plateau of the Drakensberg (c), and nearly the 

 whole portion of the Terrace, lying north of the Tugela River, 2 is 

 composed of this series, which is the coal-bearing formation of South 

 Africa, and contains the only workable coal-seams yet discovered 

 there. Prof. A. H. Green has very ably described the Molteno Beds 

 as he found them in Cape Colony, 3 and his description applies 

 generally to the series wherever it occurs in South Africa. 



There are a few points of difference, however, between the 

 Molteno Beds of Cape Colony and the same strata in South- 

 eastern Africa, the principal of which are (lstly) the absence of 

 boulders, which Prof. A. H. Green noticed as occurring in the 

 Molteno Beds in Cape Colony. These I have never found any- 

 where in Natal or in Zululand, in the districts where the Molteno 

 Beds are most exposed to view, and where admirable sections can 

 be obtained. (2ndly) The superiority of the coal over that of 

 Cape Colony. Some of the coal-seams of the Transvaal and Natal are 

 only slightly inferior to ordinary English coal, and are now taking 

 the place of the imported article for all engine work. 



The coal-beds are contained in the lower 500 feet of the series, 

 which consists principally of false-bedded gritty sandstones, with 

 inferior beds of shale, generally overlying the coal-seams, which 

 rest on gritty sandstone. 



The upper portion of the Molteno Beds consists of grey and dark 

 coloured shales, interstratified with small bands of sandstone. 



The most prominent feature of the Molteno Beds along the 

 eastern flank of the Drakensberg is a thick columnar dolerite, 

 which lies between the Molteno Beds and the ' Bed Beds,' and 

 forms a crag along the mountain-side, about 200 feet high, and 

 extending for over 100 miles. 



1 [Described by Gr. W. Stow, F.G.S., in his Reports on the Geology of the 

 Orange Free State, 1878 & 1879.— T. R. J.] 



2 This portion of the country, including Zululand, has not yet been geologic- 

 ally mapped. 



3 See Quart. Journ. Geol. Soc. vol. xliv. (1888) p. 248. 



