414 Revieics — Cape of Good Hope — Annual Geological 'Report. 



almost entirely ignored, at whioli the scientific man will lament, 

 but the practical man rejoice. 



The book is divided into three parts. Part i deals with the Pre- 

 Karroo rocks. Owing to the want in similarity of the succession 

 in different areas this portion has been divided into two sections. 

 Section 1 describes the Pre-Karroo rocks of Southern Cape Colony, 

 a subject already and more fully treated of by Mr. A. W. Rogers. 

 It, however, forms a suitable and necessary introduction to Section 2, 

 which gives an excellent and clear account of the Pre-Karroo rocks 

 of the Transvaal, together with brief descriptions of these rocks in 

 the remaining portions of South Africa. The advance made in 

 determining the puzzling stratigraphical sequence of several uncon- 

 formable and unfossiliferous formations will be gathered from 

 a comparison of the authors' conclusions with the latest published 

 results (1904) of Dr. Molengraaff. The origin of the gold in the 

 banket is seriously discussed. The authors adopt the theory of 

 subsequent infiltration. 



The Karroo and Post-Karroo rocks receive sufficient attention in 

 parts ii and iii. Part iv, describing the volcanic rocks of doubtful 

 origin, contains a chapter of 29 pages on the diamond-bearing deposits. 



The correlation of the various rock groups in part v deserves 

 the closest attention. This difficult question is clearly and philo- 

 sophically placed before the reader, who can gather in brief what 

 permanent results have been obtained and in what direction future 

 work lies. . We may state that this portion could only have been 

 written by one intimately acquainted with the recent results obtained 

 in Cape Colony, and shows the value of the work accomplished by 

 the surveyors in those regions. 



In the way of print and illustrations of fossils and rock scenery 

 nothing remains to be desired. Two excellent geological maps, 

 printed in colour, afford the reader the means of following the 

 authors' descriptions of the different regions. The introduction of 

 various tints of black and grey for the Karroo deposits does not 

 seem a happy one. Since the Karroo beds range from the Carboni- 

 ferous to the Jurassic it is scientifically incorrect ; while experience 

 in this country has proved such colours to be artistically hopeless. 

 We trust they will not receive official sanction. W. G. 



IL — Ninth Annual Report of the Geological Commission of 



THE Colony of the Cape of Good Hope, 1904. 

 rpHIS report contains a full account of the progress made during 

 X the year 1904. In completeness of detail, and in the number 

 of the accompanying illustrations and maps, it should be classed as 

 a memoir rather than as a report. 



In the Chairman's letter, and in the introduction by the Director, 

 it is stated that the work of the Survey was hampered by lack of 

 funds, so that important districts could not be visited owing to the 

 cost of hired transport. Throughout the present report we read 

 how the welfare of the colony largely depends on the water supply 

 obtained from wells and borings. It therefore seems surprising 



