56 Proceedings of the Royal Society of Edinburgh. [Sess. 
roofs of sandstone, but shale beds are fairly numerous, and it is in associa- 
tion with these shale beds that the oil-shales usually occur. 
The first point that strikes an observer familiar with the oil-shales of 
Scotland is the dissimilarity of the South African oil-shales from those of the 
Scottish fields ; indeed, it is often difficult to believe that they can be oil- 
shales at all till confronted with the results of analysis. As a rule the type 
approximates to cannel coal or carbonaceous shale, and the writer has only 
seen one seam, and that unfortunately a thin one, that is “ curly,” with the 
horny fracture and glossy surfaces familiar in Scotland. But the streak 
of these oil-shales is brown and the percentage of volatile matter high. 
The curly seam above mentioned has yielded from 60 to 85 gallons of oil 
per ton. Some seams in Natal may be described as black carbonaceous 
micaceous shales, which pass upwards and downwards into ordinary dark 
shales, but yet which contain a high percentage of volatile matter. 
At one locality not far from Middelburg in the Transvaal a thin seam of 
oil-shale lies above and in contact with a thin seam of coal : it has yielded 
40 gallons of oil per ton. In the Umkomaas and Hlatimbe valleys in Natal 
thick coaly shale seams, probably upon much the same horizon as the Indwe 
coals of Cape Colony, have yielded as much as 27 gallons of oil per ton. 
It is, however, needless to repeat instances of oil-shale outcrops that have 
been observed and often traced over wide areas, with but slight variation. 
The points to be noted are : — ■ 
(1) That the geological structure is completely different from that of 
the Scottish shale-fields, there being no folding or faulting, but the beds 
lying in horizontal sheets. 
(2) That the oil-shales are a feature of the Coal Measures, and are even 
in cases closely associated with coal seams. 
(3) That the series is largely arenaceous, though the oil-shale beds are 
associated with the more argillaceous groups. 
(4) That sudden and rapid variations in the shale seams are rare. 
(5) That the types of shale are very different from the oil-shales of 
Scotland, more nearly approximating to cannel coal. 
3. New South Wales . — The following particulars with regard to the oil- 
shale fields of New South Wales are taken from J. E. Carne’s memoir on 
The Kerosene Shales. 
The shales belong to the Permo-Carboniferous formation, which in the 
shale-field consists of a lower marine group, the kerosene shale group, 
characterised by coal seams and shale beds, and an upper group of Coal 
Measures, the whole overlaid by a thick mass of Triassic sandstones. 
