Vol. 63.~] GEOLOGY OF THE ZAMBEZI BASIX. 173 



the Batoka Basalts, I made a long journey to the place indicated, 

 at the site of the old hunter's camp known as Deka; but 

 with disappointing results. The basalts were still the lowest rocks 

 visible there ; nor could I detect in the surrounding featureless 

 country any indication that promised change, or any trace of rocks 

 other than basalt and chalcedonic quartzite in the scanty detritus 

 of the stream-beds. To the southward of this place the shallow 

 depression which constitutes the head of the Deka basin appeared 

 to merge almost imperceptibly into the great wilderness of the 

 Kalahari ; and although, in such a country, it is easily possible 

 for one to miss a vaguely-defined locality, the impression was 

 strongly borne in upon me that the search was hopeless, and that 

 in this quarter the Batoka Basalts are prolonged without inter- 

 ruption south-westward under the superficial desert-formations of 

 the Kalahari. It may be that Chapman's observation ' near the 

 source of the Luluesie (Daka) ' of ' a vertical stratum of sandy 

 schist' (oj>. tit. pp. 212-13) refers to some place farther eastward, 

 where a prolongation of the boundary-fault of the basalts is likely 

 to occur ; or it may refer only to the thin sandy flags, presently 

 to be described, that were seen to overlie the basalts in a limited 

 tract north-west of Deka (p. 196). 



At the one locality, some 3 miles south of the Wankie coal- 

 mine, where, as previously mentioned, I gained a glimpse of the 

 old rocks, they emerged from beneath the "Wankie Series in the 

 manner shown in PI. XVII, Section 2. The exposure occurred in a 

 rugged gully eroded through the sandstones, at the foot of a high 

 steep ridge which my friend and guide, Mr. J. M. Kearney, Manager 

 of the Wankie Mines, has since ascertained to be also composed 

 -of sandstone. 



In this gully, the rocks which came within reach of my hasty 

 examination (with night approaching, and no chance to revisit the 

 spot) were a schistose quartzite and a highly sheared coarse- 

 textured rock resembling a conglomerate with crushed pebbles 

 of felspar, but possibly a much-deformed pegmatite. Judging 

 from a rough sketch-map accompanying an engineer's description of 

 the Wankie coalfield published in 1902, 1 this exposure probably 

 forms the western end of a long spur jutting out from the main 

 mass of the ancient igneous and metamorphic series lying to the 

 south-east in the region described by Mr. P. P. Mennell. 2 



(2) The Wankie Sandstones and Coal-measures. 



During a stay of four days at the "Wankie coal-mine, I was 

 enabled, through the facilities afforded to me by the kindness of 

 Mr. J. M. Kearney and his staff, to make three traverses of the 

 sandstone-country between the railway-line and the Deka River, 



1 Anon. ' Colliery Guardian ' vol. lxxxiii (Feb. 21st, 1902) pp. 390-92. 



2 'The Geology of Southern Ehodesia' Special Eeport No. 2, Rhodesia 

 Museum, Bulawayo, 1904. 



