172 SCIENCE PROGRESS 



of the colony, which has been presented in duplicate to the Pietermaritzburg 

 Museum and the Imperial Institute, London. 



The concise account of the geology of the colony with which the book opens 

 will be all the more welcome that less information on this subject is available in 

 the case of Natal than in that of any other settled portion of South Africa. The 

 western border of the colony is marked by the escarpment of the great central 

 plain of South Africa, formed of Karroo beds, of which the volcanic rocks of the 

 Stormberg series constitute the summit, and the Glacial Dvvyka conglomerates 

 the base. The latter rests unconformably on the Table Mountain sandstone, 

 which Dr. Hatch correlates with the Waterberg Sandstone of the Transvaal. 

 Underlying all these is the highly metamorphosed Swaziland System, with great 

 granite intrusions. In many cases it forms the valley bottoms, while the heights 

 are crowned by Waterberg or Karroo beds. 



The greater part of the book is devoted to the economic products other than 

 coal, the mining of which is already an important industry. Some of these 

 present interesting features. Iron, for instance, occurs in ferruginous schists 

 and the less metamorphosed "calico rocks," exactly as in the Transvaal; and 

 the beds of iron oxide which are met with in the coal-measures of the Karroo 

 System can be paralleled from India. Nickeliferous pyrrhotite is found in a basic 

 rock which may be classed with the Morites, exactly as in Nyasa and at Sudbury 

 in Ontario. One of the most curious occurrences is a bed of sandstone over three 

 feet thick in the Karroo System, containing a considerable proportion of marcasite 

 and molybdenite ; of equal interest are the " reefs " and nodules of phos- 

 phate in the Ecca shales of the same System, containing scales of the fish 

 Acrolepis. 



The author very properly insists on the importance of a geological survey — the 

 absence of which in a colony of such an area and importance is very difficult to 

 understand. 



John W. Evans. 



