270 ME. A. J. C. MOLYNEUX OX THE [May I9O3, 



PL XIX, fig. 2. — This section is taken along the road from the 

 Sinanombi gold-field to the Inyoga country, along a line nearly 

 parallel to, and 60 miles east of, that of the main section. The 

 fragmental beds commence at the Djombi River with a surface -width 

 of 2000 feet of angular gravel, composed of quartz, jasper, banded 

 ironstone, and slate with numerous agates. These constituents, being 

 peculiar to the gold-belt, are doubtless the debris of an overlap by 

 the basement-conglomerate of the Mesozoic deposits. 



At the Ifaf a River, while the banks are of red ripple-marked sand- 

 stone, gneiss appears to form the bed of the water-course. 



From this river to beyond the headwaters of the Sengwe, the 

 formation is of fine red sandstone, and is followed by an exposed 

 sheet of basalt with amygdales of agate, etc. This is most probably a 

 continuation of a sheet of the same rock which occurs on the Bombasi 

 Kiver, 15 miles away to the south-west, but it is there interbedded 

 among sandstones. This sheet it is proposed to indicate provisionally 

 as the Sikonyaula Basalt. Its length has not been traced, but 

 the width is 24 miles, being abruptly cut off by the continuation of 

 the Great Escarpment, of which it here forms the capping, 200 feet 

 thick. It rests upon fine red sandstone, and at the junction of the 

 two beds there is a spring of water, near which are several silicified 

 trees. The sandstone here dips southward at an angle of 5 C . 



All the way along the foot of this escarpment run the flat 

 Matobola Plains (5 to 14 miles wide) which extend from 

 Pashu's Kraal to and beyond the Bume River, a distance of over 

 100 miles. They are composed of the finer sedimentary beds, such 

 as clays, slates, and even thin coals, comprising a distinct series 

 of deposits, Avhich may be known as the Upper Matobola 

 Beds. The disintegration of these deposits has resulted in a 

 black earth which, during the rains of summer, is converted 

 into a thick sticky mud ; but, on drying in the winter, it bakes hard, 

 and cracks into a network of fissures. It grows a rich pasture, and 

 the open plains were once the home of herds of buffalo. These 

 were decimated by the rinderpest in 1896, and only a few 7 head are 

 now supposed to exist in this region. 



PL XIX, fig. 3. — Going westward some 25 miles from the Sengwe 

 Coalfield, or from the line of the main section, over a ridge of 

 quartzites and incoherent sandstones, the native footpath comes to 

 another wide and open flat, in which occur the finer beds of the Lubu 

 Coalfield. It is probable that this flat area is connected with the 

 Matobola Plains already described, which extend to Pashu's Kraal 

 on the south-west. This basin is drained by the Lubu River, 

 which runs through a range of hills to the north-west, linking the 

 Sijarira Mountains to the Namkanya Mountains. In this locality 

 the range is still formed of coarse sedimentary beds, but the 300- 

 foot deep river-gorge shows that these rest upon gneiss and peg- 

 matite. The section figured was taken along the footpath that runs 

 from the coal-exposure in the Lubu River, passing the Native 

 Commissioner's camp, and over the low spurs at the western end of 



