134 Reports and Proceedings— Geological Society of London. 



north-western side, however, is almost precipitous, and is capped by 

 folds of quartzites. There is a drop of 1,100 feet in a few miles, and 

 the rest of the country is almost flat as far as the Zambesi Eiver. 

 To the west is the gorge of the Lubu Eiver, and it is there seen that 

 the sediments rest upon pegmatites and gneiss. 



Another section shows the contact of fine sediments and meta- 

 morphic rocks down the railway-line to the south-west past Sisi 

 siding, where certain plant-remains were found. By these sections 

 the boundary or line of unconformity is traced from the Mafungi- 

 busi district, round the promontory of granites and shales which 

 form the backbone of Matabeleland, to the Tuli district and Sabi 

 Eiver on the south. Except in the Tuli district, where an uncon- 

 formity between the veined sandstones and the Coal-measures is 

 noticed, there are no definite breaks in the order of stratification ; 

 and it is by the general arrangement of superposition and characteristic 

 features that the strata fall into certain groups. No attempt is made 

 to correlate the strata with the Cape and Karoo systems ; and for the 

 present the author gives the following provisional classification : — 



Thickness in feet. 



Taba 'Sinduna Series Sandstones and volcanic rocks 200 



Forest Sandstones 1000 



Escarpment Grits 400 



Upper Matobola Beds ^^ Coal-measures 300 



(fossiliferous). 1 



Busse Series l Sandstones and grits 300 



(fossiliferous). I 



Lower Matobola Beds J Coal-measures ... 200 



£!•• ■ Q • ( Quartzites and current-bedded sand- 

 Sijanra Series | ^^^^^^ 2000 



Great unconformity. 

 Basement- rocks : Gneiss, schists, and pegmatites of Mafungibusi 

 and Lubu. 



Fossils have been found in the Coal-measures, comprising mollusca, 

 plant- and fish-remains, which are described in appendices. These 

 indicate the age of these beds to be Permo-Carboniferous. 



The Coal-measures yield coal of excellent quality, and the areas 

 in which seams outcrop, or have been developed, are described under 

 the names of the Mafungibusi, Sesami, Sengwe, Lubu, Sebungu, and 

 Wankies Coalfields in the north, and the Tuli and Sabi Coalfields in 

 the south. 



Eeference is made to the numerous mineral springs, of varying 

 temperature, that are dotted along the Zambesi Valley, and to 

 mounds of travertine, containing recent fresh-water and laud shells, 

 that have been accumulated by extinct springs. 



Volcanic rocks are well displayed in a long area extending from 

 Macloutsie to the Bubi Eiver, 200 miles ; and the extinct craters 

 are still recognizable at Fort Tuli, which gives the name to this 

 tract of Tuli Lavas. Sheets of basalt are interbedded with the 

 Forest Sandstones at the Bubi and Gvvampa Eivers ; and at a portion 

 of the escarpment above the Sesami Coalfield, basalt forms a capping 

 and extends back about 24 miles. 



Three a2)pendices are added : one, on a New Species of Acrolepis 



