Reviews — Geology of the Barherion District. 371 



I. — The Geology of the Bakbekton Gold-mining District. By 

 A. L. Hall. Memoir No. 9 of the Geological Survey of the 

 Union of South Africa, pp. 347, with 58 plates, 40 text-figures, 

 and a coloured map. Pretoria, 1918. Price 7s. 6d. 



IN this comprehensive memoir Mr. Hall gives a detailed account of 

 the physiography and geology of the important Barberton gold- 

 mining district in the Eastern Transvaal and Swaziland. The 

 physical characters of the region present many features of interest : 

 in the west comes the great Drakensberg escarpment, here consisting 

 mainly of strata of the Potchefstroom or Transvaal system. The 

 "Barberton Mountain Land", consisting of a large number of 

 mountain ranges, is composed chiefly of the slate- quartzite group of 

 the Moodies Series, while in the south is a great granite plateau. 



The area shows a typical development of the Swaziland system, 

 which is subdivided into three groups, the Onverwacht Volcanic 

 Series, the Moodies Series, and the Jamestown Series : each of these 

 is penetrated by the older granite, while the Transvaal system rests 

 on all of them with a major unconformity. It is shown con- 

 clusively in this memoir that the granite is of later date than the 

 Swaziland rocks, and the chief interest of this point lies in the fact 

 that the gold reefs are mainly to be found in the metamorphic 

 aureole of this granite. The Xarroo System covers only a small 

 area, including the Komatipoort coal-field. The Moodies Series 

 consists of sedimentary rocks, chiefly slates and quartzites, whilst 

 the Jamestown Series now takes the form of chloritic and talcose 

 schists and other types probably derived from basic igneous rocks, 

 rather like the Keweenawan of North America. The later basic 

 intrusions are of little or no economic importance. 



Besides the gold-fields of the De Kaap area and Northern Swazi- 

 land, the district also possesses economic possibilities in the form of 

 extensive deposits of raagnesite and talc, while cassiterite has also 

 been worked on a small scale in one or two localities. 



E. H. R. 



II, — Beport op the Mines Branch of the Department of Mines, 

 Canada, foe the year 1916. pp. 183, with 14 plates and 

 10 figures. Ottawa, 1917. Price 25 cents. 



THIS report contains a general summary of the work of the 

 Department for the year, together with individual reports on 

 various subjects that have been specially investigated. Among 

 these are notes on occurrences of iron-ores and building and orna- 

 mental stones, and on a reconnaissance for phosphate in the Eocky 

 Mountains and for graphite in British Columbia. In Canada, as in 

 England and in the United States, much attention is now being paid 

 to sands suitable for metallurgical purposes, and a large amount of 

 work has been carried out by tlie Department on this subject. 

 Attention was also paid to the possibility of removing lime from 

 impure magnesite, such as is found in the Grenville district; this is 



