Vol. 65.] KARROO SYSTEM 1ST NORTHERN RHODESIA. 415 



Some 10 miles down, the river is joined by the Mkushi, lying 

 deep below the contiguous country, but with fairly soft slopes, 

 which contrast with the ' new ' appearance of the canon-walls at 

 the Lusenfwa Falls. Five miles onward the latter debouches into 

 the Luano — falling over 1000 feet in its course from the falls. 



It then heads straight across the Karroo floor for the inlier 

 of Kasafa Mountain (Archaean), through a shoulder of which, some 

 500 feet above the plain, it passes by a deep and gloomy gorge. 



The Malenji is situate to the west of the Lusenfwa, and is 

 remarkable in that it emerges from a ' hanging valley ' cut down 

 about 300 feet below the escarpment-crest, whence it falls down 

 the face of the precipice, or dip-slope of the gneiss, passing behind 

 a ridge into a rocky defile. It flows only in the summer ; and then 

 its white cascade of over 800 feet, gleaming among the deep green 

 foliage, presents a beautiful feature, visible from afar ia the Luano 

 Valley. 



Farther west, again, — with many unknown streams intervening 

 of a similar type, — comes the Kobwe, and then the Lungu. 

 The latter gorge receives a waterfall, and runs into the deep canon 

 of the Molongushi, near its confluence with the Mwomboshi. 



These three converging streams have been accountable for a con- 

 siderable area of erosion, the waters passing into the Luano plain 

 at Mount Jowlila. While the Lungu and Molongushi come over 

 waterfalls and follow canons cut across the strike of the gneiss, 

 the Mwomboshi, as a contrast, belongs to the type that adheres to 

 the strike of the cleavage, and its descent to the plain-level is in 

 a gradual course for many miles. 



The Molongushi River has the usual sluggish course in its 

 plateau-reaches, and eventually passes through a range 3 miles 

 north of the falls, formed of metamorphosed sedimentary strata. 

 The country then feels the influence of the more rapid drainage 

 over the plateau-edge, and becomes much broken by watercourses. 

 It is among these forest- covered ridges that the thunder of falling 

 water reveals, and attracts one to, the most beautiful of all these 

 lateral canons in the Machinga escarpment. 



This of the Molongushi is about 1000 feet deep, and although 

 the volume of water passing down is less than that of the Lusenfwa, 

 — it nearly ceases in winter, — the canon and surrounding features 

 are deeper, wider, and grander. One is immediately struck by the 

 repetition of the methods of degradation of the Machinga escarp- 

 ment on the walls of this great cavity. Overhanging ledges and 

 precipices are noticeable immediately near the falls, but the further 

 parts of the gorge are more sloping, and the long streaks of white 

 where landslips have torn down the trees in a descent that is 

 generally complete from top to bottom, are evidence that the walls 



