Lysurn—Wining and Minerals in the Transvaal, ete. a3) 
Numerous sheets of igneous rock are interbedded with the quartz- 
ites. The series is devoid of fossils. To the north of Pretoria the 
shales contain galena. 
The Karoo System.—This system comprises the sandstones, 
shales, and Coal-measures. The sandstones are arkose in character. 
Red sandstone predominates at the surface, and is characteristic 
of the coal-bearing deposit. It is hard and compact where exposed. 
Shales are found underlying the sandstones. The formation may 
be divided into the Upper and Lower Karoo. Ishall only refer to 
the Molteno beds, which are coal-bearing. The distribution of 
these beds has hitherto been imperfectly worked out; they are 
met with in the Cape Colony, extending into the Middleburg 
district of the Transvaal, and are traceable into Orange Free 
State, Natal, Zululand, Pondoland, and the Portuguese territory ; 
they mostly lie in a horizontal position; their age is an open 
question. The fossils so far obtained are Sigil/aria and G'lossopteris 
(the latter is also met with in the Indian Trias). From my own 
observation, I estimate the coal area of South Africa to be about 
175,000 square miles, or, say, about 400 miles by 440. 
Recently a coal seam of the abnormal thickness of 211 feet has 
been discovered to the east of Johannesburg, on the farm Zuur- 
bekom. I consider this to be one of the greatest coal discoveries 
of recent times. The sandstones and shales overlying the coal, 
totaling 320 feet. As to the quality of South African coal, it may 
be stated that its average calorific value is about 1 lb. for 7 lbs. of 
steam compared with Welsh coal, 1 lb. of which gives 11 or 12lbs. 
of steam. 
Mining.—The underground development is performed by 
means of rock-drills driven by compressed air, white miners ope- 
rating the machines. ‘Stopping,’ or breaking down the ore, is 
done by hand, and the work alloted to Kafirs, supervised by white 
miners, who charge and fire the blasts. Machine stopping is 
replacing the hand method. 
The deposits of the Witwatersrandt are at present worked by 
rectangular shafts, both vertical and inclined. In the early days 
of the industry, vertical shafts were much preferred, cross-cuts 
being driven to intersect the reef. At the present time the out- 
crop properties are being worked by inclined shafts, or, in other 
words, shafts sunk on the reef. Inclined shafts are preferred 
