142 G. T. PEIOR. 



rocks of the Lebombo Range, and norites and pyroxenites of 

 the Umqueme Range in north Zulnland, as well as pebbles 

 from the Dwyka Conglomerate at Park Rynie, Natal, and a 

 few examples of granites, gneisses, pyroxene-granulites, and 

 hornblende-schists of the Archaean Series. 



DOLERITES. 



The widespread occurrence of intrusive dolerites is one of 

 the characteristic features of South African geology. In 

 Natal and Zululand, according to Anderson, they are almost 

 universal in their occurrence as dykes and sills of enormous 

 extent, intrusive in all formations up to the top of the Upper 

 Karoo. 



Of the numerous localities in Natal from which specimens 

 were obtained may be mentioned Dundee, Ladysmith, New- 

 castle, and Majuba Hill in the north ; the coast region 

 between the mouths of the Sinkwazi, Umvoti, Tongaat, and 

 Umhlali rivers in the east ; the HlangAveni Valley, Glendale, 

 Kearsney, and Stanger in the Lower Tugela district ; and 

 Ixopo Creek and Inhlazan Mountain (almost the entire mass 

 of which is stated to consist of dolerite) in the south-western 

 district. 



In Zululand, according to Anderson, these rocks attain their 

 greatest development immediately to the south and east of the 

 St. Lucia coal-field, and form the Entondweni Mountains and 

 the eastern half of the Makowe Hills. Besides specimens 

 from these localities the collection contains others from the 

 Hlabisa District, Intambanana Creek, Mona Creek, Umlalaas, 

 Nkandla, and the Umqueme Range. 



The mineral and structural characters of dolerites from 

 South Africa have been often described. In their general 

 characters the specimens from Natal and Zululand in the 

 present collection are similar to those (chiefly from Cape 

 Colony) minutely investigated by Cohen and others. '^ The 



1 See Cohen, 'Neues Jahrb. f. Min., etc.," V. Beil Band. 18S7, p. 195 ; 

 and Rogers, ' The Geology of Cajje Colony,' 1909, p. 258. 



