278 MR. A. J. C. MOLYNEUX ON THE [May I903, 



stratification between the Samkoto Sandstones and the coal-bearing 

 beds, there appears to be no evidence of any unconformity whereby 

 the large area and great thickness of sedimentary beds of Southern 

 Rhodesia might be divided or grouped into separate systems — river- 

 deposits and superficial accumulations excepted. Fossils have only 

 been found in the beds associated with the coal-bearing strata, and 

 thus there are no palseonto logical reasons for dividing the rocks 

 into groups. There is only the general basis of superposition, and 

 from the sections given, and from their characteristic, lithological 

 features, the rocks naturally fall into certain groups. No attempt 

 is here made to correlate the strata of Southern Ehodesia with the 

 Cape and Karoo systems ; and so, for the present, I have ventured 

 to apply names to the groups, taken from the localities where each 

 is most typically developed. 



The following provisional classification of the sediments that lie 

 between the higher plateaux of Southern Rhodesia and the Zambesi 

 River is accordingly suggested : — 



Thickness in 

 feet. 

 Tbaba 'Sinduna Series . 200 Sandstones and volcanic rocks of Thaba 



Sinduna and Shiloh. 



Forest Sandstones 1000 Fine sandstones of the forest-country, with 



sandy clay. Travertine on the surface. Bubi, 

 Gwampa, and Sikonyaula basalts. Con- 

 glomerate-basement near the Djombi River. 



Escarpment-Grits 400 Coarse red sandstones, with subangular pebbles, 



as seen in the great escarpment which 



stretches from the Mafungabusi Mountains 



to near Wankie's. 



Upper Matobola Beds... 300 Clays, shales, ironstones, limestones, and im- 



(with coal-bearing pure coals of the Matobola Plains, from the 



beds: fossiliferous). Mafungabusi Mountains to the Gwai River. 



Busse Series 300 Fissile sandstones, grits, and conglomerates, 



(local only ? : fos- with well-rounded pebbles. 



siliferousV 

 Lower MatobolaBeds... 200 Shales and workable coal-seams, 

 (with coal-bearing And at the base 



bed?). Fine, fissile, ripple-marked sandstones (car- 



bonaceous). 

 Siiarira Series 2000 Quartzites, indurated shales, and current- 

 bedded sandstones and grits of Sijarira and 

 the Zambesi. 



Great unconformity. 



Basement-rocks Gneiss, red and white pegmatite, and coarse 



granite, of Mafungabusi and the Lubu 

 Gorge. 



In the Mafungabusi district there has been no uptilting of lower 

 beds, and the thickness of the sedimentary strata must be ascertained 

 by the erosion of horizontal beds, reckoned from the highest sand- 

 stone of the Mafungabusi Mountains (3000 feet) to the Zambesi 

 (1100 feet), a depth of 1900 feet. 



The altitude of Thaba 'Sinduna is 4600 feet above sea-level, or 

 1600 feet above the Mafungabusi Mountains, and thus in the north- 



