Vol. 59.] SEDIMENTARY DEPOSITS OF SOUTHERN RHODESIA. 271 



the Sijarira Range, to the Zambesi River at Binga's Kraal, a distance 

 of about 30 miles. 



Among the shales revealed by the erosion of the Lubu River 

 while crossing the flat, several seams of workable coal of excellent 

 quality may be seen. At one especially noticeable point these deposits 

 are tilted against a prominent reef of quartz some 30 feet high, and 

 extending in a north-easterly direction for 200 yards. Here the 

 dip of the beds is 15° to the south-east. Proceeding farther down 

 the river, this high angle gives way to a general dip of 5° south- 

 ward, and one mile still farther down the river -sandstones come 

 in and continue as the surface-rock as far as the Sijarira footpath. 

 The river then runs into its deep gorge, which has a circuitous 

 length of about 9 miles. The section of the rocks revealed in the 

 walls of this chasm gives the following approximate measurements: — 



Thickness in feet. 



Current-bedded sandstones, with local indurations 100 



Grey sandstones, with irregular pebble-beds 50 



Red shales 50 



Coarse red sandstones 20 



Eed shales 50 



Angular grey conglomerate, compact, with pyrites 10 



Gneiss Basement, 



The dip of these beds is still consistently southward, but there arc 

 local disturbances with axes following a general easterly-and-westerly 

 direction. These are the result of earth-movements, and show 

 for their central cores dykes of a crush-breccia, made up of angular 

 blocks of red or grey quartzite cemented together by white silica. 

 Where these dykes have been cut through by the river, the 

 cementing silica takes on the chalcedonic form, showing distinct 

 banding as in agates. 



Ascending from the river-gorge, the footpath towards the 

 Zambesi goes below the high western end of the Sijarira Range, 

 and the denudation of the sedimentary strata there reveals a belt, 

 about 6 miles wide, of the basement-gneiss and granites, north of 

 which the sandstones again occur and extend to the Zambesi. 

 The contact with the crystalline rocks in this direction is hidden 

 under debris or wash from the hill. But the sedimentary deposits 

 may be seen farther on to consist of false-bedded and coarse sand- 

 stones, the current-bedding occurring very frequently. The last 

 exposure of these rocks on the south side of the Zambesi River is 

 where they form a far-stretching bluff or escarpment about 200 feet 

 high, taking a north-easterly and south-westerly direction, and 

 forming the wall of the river-valley for many miles. At Binga's 

 Kraal the alluvial plain is some 5 miles wide, and the river, which 

 here is about 300 yards in breadth and a gentle, navigable stream, 

 takes a winding course across the valley between the southern and 

 opposite hills. 



The exposure of crystalline rocks under the end of the Sijarira 

 Range takes also a south-westerly direction towards, and disappears 

 under, the high Namkanya Mountains, a range conspicuous from the 



