572 Bevieivs — Dr. Beinisch's Petrography. - 



rWitteberg Series. 

 CAPE SYSTEM. ■] Bokkeveld Series. 



[Table Mouutaiu Series. 



Pre-Cape Eocks : — 



In the south aud west of the Colony — 



Ibiquas Series. 



Caugo Series. 



Malniesbury Series. 

 In the north and north-Trest of the Colony — 



Matsap Series. 



Griqua Town Series, 



Campbell Rand Sei'ies. 



'Keis Series. 



Namaqualaud Schists (?). 



The age of the pre-Cape Rocks (Primary of Schenck), among 

 the different members of which two, and probably three, uncon- 

 formities have been detected, is left an open question ; it being only 

 suggested that some of them may eventually prove to be of Lower 

 Palaeozoic age. We ourselves have been struck with their many 

 resemblances to the pre-Cambiian rocks of India. The overlying, 

 unconformable Cape System is considered to be probably the 

 equivalent of the Lower Devonian of other countries. The classi- 

 fication of Schenck is adopted for the Karroo System, excepting in 

 the separation of the Dwyka Series from the Ecca Beds. Whether 

 the Uitenhage Series and the Cretaceous Series of Pondoland may be 

 placed together in a Cretaceous System depends upon the results 

 obtained by the palaeontologists, who have not definitely settled the 

 age of the Uitenhage fauna and flora. Walcot Gibson. 



IL — Pbtkographisohes Praktikum : zweiter Teil : Gesteine. 

 By Dr. Reinhold Reinisch. Large 8vo ; pp. vii, 180. 

 Berlin, 1904. 



rpHIS is a practical guide to the study of rocks, written by one 

 JL familiar with teaching. The characters of the several rock- 

 forming minerals having been dealt with in the former part of the 

 ■work, dated 1901, the author is able to plunge directly into 

 the systematic description of the rocks themselves. About three- 

 fifths of the book is devoted to the eruptive rocks, which are treated 

 under comprehensive heads which we may call families. For each 

 family the author gives a brief notice of the chief component minerals, 

 the structural peculiarities, the more important types included in 

 the family, and a selection of chemical analyses. The rather 

 conventional arrangement is based on that of Zirkel, the principal 

 divisions being characterized by the preponderance of alkali-felspars, 

 of lime-soda-felspars, or of felspathoids, or by the absence of all 

 these minerals. The discarding of the ' dyke-rocks ' leads to 

 confusion in some places, as e.g. when minette and vogesite are 

 grouped with the orthophyres, etc. On the other hand, the dis- 

 tinction made in most of the families between the ' Alkali ' and 

 the ' Alkalikalk ' groups is one which may profitably be impressed 

 on the student. The practical point of view is constantly maintained 



