Vol.65.] KA.RR00 SYSTEM IN NORTHERN RHODESIA. 429 



clay in lenticles and pellets, which on removal leave flat almond- 

 shaped cavities. The rock, on fracturing, shows a fibrous surface 

 with a silky sheen. From nodules in the vicinity I obtained fossil 

 ostracods, and a pink limestone, with clayey lenticles, yielded 

 Palceomutela. 



Earthy limestones at Manaunga's, close under the Maohinga, 

 yielded spines and teeth, bones, and unioniform shells. 



The Escarpment Grits. 



These are best seen at the south-western end of the Zambesi 

 Basin — Sengwe and Wankie — where they present much greater 

 development than farther north. 



In the Luano the few noted areas of these deposits lie along 

 the western side of the depression, near the Machinga wall and 

 dipping towards it. Mr. Moubray informs me that they occupy such 

 a position at Chipawa. I have seen them near the Lusenfwa gorge, 

 Mashate's village, and at Manaunga's. At these last-named localities 

 they form long red ridges parallel with the Machinga, with dip-slopes 

 to the north-west. At Mashate's the ridge dies down to 40 feet in 

 height, its upper part being of red grit, with angular fragments of 

 quartz oriented, and placed at varying intervals. Under this is a 

 mas3 of rounded pebbles and boulders, occasionally bedded, and 

 generally unsorted. Boulders measuring 12 inches in longest 

 diameter occur. The pebbles are of tourmaline-schist, quartz, 

 quartzite, and gneiss : this last is soft and rotten, and there are 

 other fragments of a soft ferruginous clay in which minute yellow 

 quartz-veins exist. In this occurrence of soft pieces lies a differ- 

 ence from the basal conglomerates. From the latter such soft rocks 

 would have been removed by the grinding movement — here a mere 

 throwing-down in eddying currents was the only feature. There 

 are no cracks, joints, or shearing visible. 



At Manaunga's the ridge of these rocks lies about a mile from 

 the foot of the plateau-wall, dipping 20° north-north-westwards. 

 They overlie conformably the septarian clays, and comprise grits and 

 hard red clays along a surface-belt of 4000 feet. The grits, with 

 pebble-layers, weather soft in places, but elsewhere are more resisting. 

 There was noticed a series of bands of grit, each 18 inches deep, 

 with a layer of pebbles at the bottom, but passing upwards into 

 fine current-bedded sandy clay — denoting some repeated condition 

 of deposition. 



The intercalated clays are hard, sometimes calcareous, deep red 

 in colour, and weather in spherical blocks. 



Low escarpments of the same type occur between the Losito and 

 Lufua Rivers, where they form a line of red cliffs facing the 

 Machinga. 



The Forest Sandstones. 



I have only noted the existence of the fine-grained rocks of this 

 type in the Zambesi Plain, where the Losito Biver passes through 

 cliffs, 30 feet high, of pink sandstones with current-bedding, and 



