1885.] Indwe and Cypher gat Coal Beds, 45 



stated, there is workable coal in Queensland in two horizons. The 

 coal-fields of Virginia are of Triassic age. Workable coal is found 

 in Queensland of the Miocene period. As far as we know the greatest 

 development of the mineral called coal is in connection with rocks of 

 the carboniferous period. The view that there must have been a 

 greater amount of carbonic acid (carbon dioxide) in the atmosphere, 

 then, is only held now by imaginative chemists. The presence of 

 carbonic acid gas in the air to any considerable extent would prevent 

 the heat of the sun from penetrating it to the soil. 



The absorptive power of the atmosphere as at present constituted 



is I, 

 As compared with that of carbonic acid, which is as much as 972. 



A proper knowledge of Elementary Physics would keep such men 

 from views so diametrically opposed to the true spiiit of uniformita- 

 rianism in geology. There are, as Lyell states, in New Zealand and 

 in Scotland processes going on now which would furnish material for 

 a great coal deposit, and doubtless there have been parts of the globe 

 similarly favoured in all geological ages. It has been observed by 

 geologists that the coal-fields of Britain occur in troughs and hollows 

 protected by volcanic outbursts ; and therefore to the upheavals and 

 igneous energy subsequent to the deposits of coal that country owes 

 its possession of great riches in this mineral. In other periods it 

 must have been similarly situated geographically, but on account of 

 the absence of protection by volcanic outbursts the vegetable deposits 

 have been washed away and scattered and dissipated. 



The position of the coal-bearing beds of South Africa, which have 

 produced the fos-ils referred to and described may be graphically 

 represented as follows, taking a diagonal section from Table Bay to 

 the Stormberg : — 



Tertiary Deposits. 



Meagrely represented by surface gravels, &c. 



Mesozoic Rocks. 



Cretaceous. — Stormberg and Diamond Fields. Volcanic vents. 

 Jurassic. — Molteno, Cyphergat, and Indwe. Coal-bearing beds. 

 Triassic. — Upper Karoo. (Bain). 



Palaeozoic Rochs. 



Permian. — Lower Karoo (Bain) and Ecca beds (southern slope of 

 the Boggeveld and Kimberley Reef). 



Carloniferous. — Witteberg, &c., but without workable coal. 

 Devonian — ?7^jt?^r - — Warm Bokkeveld. 

 Devonian — Lower. — Table Mountain Sandstone. 

 Silurian. — Clay slate of Lion's Rump. 



