176 THE GEOLOGY OE THE ZAMBEZI BASn*. [May I907, 



Wankie, I noticed a few rounded boulders of schistose quartzite, 

 up to 8 or 10 inches in diameter, embedded in the sandstone ; 

 but I did not, at the time, appreciate the suggestiveness of the fact 

 as a possible indication of the horizon of the Dwyka Conglomerate. 

 I must be content, therefore, to throw out the hint, in the hope 

 that it will attract the attention of some future worker to this 

 place. 



In the carbonaceous sandy shale (Bed 3 of Section 2) exposed at 

 the Wankie railway-station and in a bank near the entrance to the 

 mine, obscure fragments of plants are abundant ; while in the shale 

 forming the roof of the mine, Mr. Kearney pointed out to me some 

 crushed reed-like stems measuring several feet in length, and 3 or 

 4 inches in breadth ; but all were too imperfectly preserved for 

 determination. 



I obtained rather better specimens, however, from a brown silty 

 shale in the section 4^ miles west of Wankie (Bed 5 of Section 3) 

 exposed in a little gully between the old wagon-road and the 

 railway, here running within 100 yards or so of each other. Among 

 these specimens, Prof. A. C. Seward has recognized fragmental 

 Vertebraria; and if this fossil is, as supposed, the stem of Glosso- 

 pteris, it confirms Mr. Molyneux's correlation of these measures. 



In the character and predominance of the sandstones; in the 

 prevalent sandiness of the shales ; and in many other features, these 

 deposits differ greatly from our British Coal-Measures, and indicate 

 very different conditions of accumulation. 



The grounds on which a belt of the Wankie Series is inserted on 

 the map (PI. XVII) to the northward of the basalts have already 

 been stated (p. 172) and require no further discussion. 



The- Deka Fault. 



On finding that the monotonous basalt-country, after sinking 

 steadily eastward, came at last to an abrupt termination at the foot 

 of the steep hill-range of sandstone and quartzite bordering the 

 southern side of the Deka Valley, my first impression was that 

 the Batoka Basalts had shelved underneath the sandstones; and, 

 although there were difficulties in the interpretation, it was with this 

 idea in mind that I reached the Wankie coalfield. But the idea 

 became untenable when I ascertained that metamorphic rocks, and 

 not the basalts, emerged on the south from beneath the coal-series. 

 Returning to the Deka, therefore, to make further examination, I 

 soon obtained clear evidence that the junction was in truth a line 

 of faulting, the actual fault being well exposed in the river-bed 

 near the Deka railway-bridge, within a mile below the place where 

 I had first crossed the junction. By another journey northward 

 from Wankie to the Deka, at the confluence of its tributary the 

 Eondulu, some 7 or 8 miles lower down the valley, I was enabled 

 again to intercept the fault, which was here even more strikingly 

 displayed. It then became evident that a faulted junction of the 



