754 H. A. BROUWER 



Nearly at the same time as Hubner, Carl Mauch 1 made geog- 

 nostical studies in the central part of South Africa. In a chapter, 

 "Mein erstes Jahr in der Transvaal Republik," he describes his 

 "Irrfahrten in den Pilaans-Bergen." Coming from Rustenburg, 

 he passed a conical hill and entered the central part of the mountain 

 complex and found "quartz porphyries" with a violet-brown 

 groundmass in the bed of a rivulet. After nearly perishing with 

 hunger and thirst, he was received hospitably in the house of the 

 missionary, who still lives in the native stadt on Saulspoort. From 

 the western part of the mountains he mentions pieces of copper 

 ore, magnetite, fluorine, and pebbles of gneiss. Most probably 

 his quartz porphyries are the rocks without quartz, with por- 

 phyritic feldspars in a reddish, dense or fine-grained groundmass, 

 which are the effusive equivalents of the syenites and nepheline 

 syenites of this region. His gneiss probably is the schistose lujaur- 

 ite which covers large areas in the western and southern part of 

 the mountains. 



In his sketch of the South-African Republic, G. A. F. Molen- 

 graaff 2 gives a review of the knowledge about the rocks of the 

 Bushveld, and here the results of Mauch and Hubner are mentioned. 



In 1898 J. A. L. Henderson 3 described a syenitic rock from the 

 Pilandsberg as pilandite. The true character of the rocks of the 

 Pilandsberg was recognized by Molengraaff 4 in 1904. In a short 

 geological description of the Pilandsberg and a part of the Rusten- 

 burg district he mentions that different varieties of foyaites are of 

 widespread occurrence and the schistose varieties, which are very 

 rich in aegerine, are compared with the lujaurites of Greenland. 

 The rock specimens, which Molengraaff collected, were studied 

 by me, and the results of this study were published in the petro- 



1 Carl Mauch's "Reisen im Innern von Siid-Afrika, 1865-1872," Erganzungs-Bd. 

 VIII (1873-74), Peterm. Geogr. Mitt. No. 37. 



2 G. A. F. Molengraaff, "Schets van de Bodemgesteldheid van de Zuid- 

 Afrikaansche Republiek," Tijdschr. Koti. Aardr. Gen. (Leiden, 1890), p. 604. 



3 J. A. L. Henderson, On Certain Transvaal Norites, Gabbros, Pyroxenites and Other 

 South-African Rocks. London, 1898. Dulau and Co. 



4 G. A. F. Molengraaff, "Preliminary Note on the Geology of the Pilandsberg 

 and a Portion of the Rustenburg District," Trans. Geol. Soc. South Africa, VIII (1905), 



