5— GEOLOGICAL NOTES ON THE COAL AND GOLD 

 DEPOSITS IN NATAL. 



By C. J. Gray. 



Coal occurs in almost every part of the Colony, the seams 

 being of two ages. Mr. Anderson, lately Government Geologist of 

 Natal, has pointed out* that the coal in the Drakensberg in the 

 Polela division (being accompanied by a Thinnfeldia fossil flora) is 

 of Stormberg age, and more recent than the other coals, which go 

 with a Glossopteris flora. This Stormberg seam is about 5,750 feet 

 above sea level, and the actual coal, which is little more than 2 feet 

 thick at the best exposures, is very bituminous near the headwaters 

 of the Umkomaas, and there grades into bituminous shales, but it 

 becomes more anthracitic and unaccompanied by shales to the 

 southward. 



Mr. Anderson classes the lower and far more important seams 

 in the Ecca series, including in that term, the Glacial Dwyka Con- 

 glomerates ; the dark-coloured non-fossiliferous Pietermaritzburg 

 shales lying immediately above the Dwyka ; the light-coloured shales 

 and sandstones forming the upper portion of the Pietermaritzburg 

 shales ; and the still higher sandstones and shales containing 

 abundant Glossopteris and some reptilian remains in which the coal 

 seams occur. The series is separated from the Stormberg beds by 

 the Beaufort claystones, fine grained sandstones and shales, con- 

 taining more abundant reptilian remains. 



It has been my practice to divide the series into three divisions, 

 viz., the Dwyka, the Ecca shales, and the Natal Coal Measures, and 

 I consider that those divisions should be recognised in all geological 

 mapping and other geological work in the Colony. The divisions 

 are distinct in petrological character, and for that reason can be 

 readily distinguished in the field. The coal measure shales generally 

 show remains of fossil flora, while the Ecca shales do not show such 

 remains, though in places they contain thin and valueless anthracite 

 seams and graphitic beds. Even in hand samples the distinction 

 can generally be made with some approach to certainty, as the coal 

 measure shales are as a rule less dense in texture, and either more 

 sandy or micaceous than the older shales. From the economic point 

 of \'iew their recognition is of great importance, as the economic 

 products (either minerals or building stones) of the different divisions ; 

 their characters affording water supply, the soils resulting from 

 their weathering; and their influence on topography; all differ 

 greatly. 



I do not urge that the terms which I use to indicate the divisions 

 are the best, or undoubtedly correct. The apparent absence of fossils 

 in what I call the Ecca shales may indicate that the class is older 

 than the Ecca shales of the Cape Colony, and would be more correctly 

 termed the Dwyka shales. The shales, though nearly i.ooo feet 

 thick at Maritzburg, thin out inland, so that they are only a few 



* Second Report. Geol. Survey of Natal. 



