266 mr. a. j. c. molyneux on the [May 1903, 



20. The Sedimentary Deposits of Southern Rhodesia. By Arthur 

 J. C. Molynettx, Esq., F.G.S. With Appendices by Dr. A. Smith 

 Woodward, F.R.S., F.L.S., F.G.S., Dr. Wheelton Hind, B.S., 

 F.R.C.S., F.G.S., and E. A. Newell Arber, Esq., M.A., F.G.S. 

 (Read January 21st, 1903.) 



[Plates XIX & XX.] 



Contents. 



Page 



I. Introduction 266 



II. The Northern Sediments 267 



III. The Physical Features and Grouping of the Rocks... 275 



IV. The Fossil Remains 280 



V. The Coal-Deposits 281 



VI. The Thermal Springs and Travertine-Beds 282 



VII. Summary 283 



VIII. Publiographical List 284 



Appendix I 285 



Appendix II 287 



Appendix III 288 



I. Introduction. 



Southern Rhodesia lies between the Rivers Zambesi and Limpopo 

 where they approach nearest to each other, a distance of 400 miles. 

 Its greatest breadth is from the Victoria Falls on the west to the 33rd 

 degree of longitude on the east, a distance of 450 miles, and it has 

 an area of 192,000 square miles. The major portion of this extent 

 is occupied by grey granite and gneiss, and by the metamorphic 

 schists and slates that contain the numerous quartz -veins extensively 

 worked by an ancient people, and now being again opened up for 

 the extraction of gold and copper. The area over which these rocks 

 occur measures 140,000 square miles, the remaining portion being- 

 taken up by sandstones and volcanic rocks. 



Whatever may have been the original condition of the slates and 

 schists of the gold-belts, igneous or sedimentary, they are now so in- 

 durated and cleaved by lateral pressure that their present state only 

 is recognized in this paper, and they are referred to as schists or 

 metamorphic rocks, or when associated with the granites and 

 gneisses, arc included in the term Archaean rocks. The slates 

 lie at an almost vertical angle, and the lapse of time and vast amount 

 of erosion that took place before they were covered by the deposition 

 of the sedimentary beds now to be described (which, in striking 

 contrast, lie at low angles or horizontally) give rise to the ' great 

 unconformity ' of Rhodesian geology. 



The Archaean rocks of Rhodesia have frequently formed the 

 subject of scientific communications ; but, so far as I am aware, no 

 notices have appeared on the sedimentary deposits of the country, 

 and it is the object of this paper to set forth briefly the result of 

 observations made in travelling over the area occupied by these 

 rocks. 



