196 MR. Gc. W. LAMPLUGH OK THE [May I907, 



the district, 1 and this view of the age of the Batoka Basalts is 

 accepted by Mr. Molyneux in his later description of the Victoria 

 Falls. 2 



The second view is that implied in Dr. Passarge's above-mentioned 

 correlation of the Batoka Basalts with the Loale Amygdaloid and 

 Diabase (' Loalemandelstein '). Here again the age of the rocks 

 with which the comparison is made remains itself uncertain ; but 

 Dr. Passarge suggests that the ' Loalemandelstein ' may fall within 

 the Jurassic Period, pertaining possibly to some stage of the great- 

 epoch of volcanic activity represented by the Stormberg Series of 

 the southern colonies. 3 



Further exploration will doubtless in time bring to light more 

 direct evidence on the point ; but my own endeavour to obtain such 

 evidence having been unsuccessful, I can only state my impression, 

 based mainly upon the relation of the basalts to the physical 

 structure of the country, that they are likely to prove older than 

 Tertiary. That they are older than the planation of the great 

 plateau of which they form part is evident from the structure 

 of the country around the Deka Fault ; and if we dare follow 

 Dr. Passarge in considering that this planation was largely accom- 

 plished during a Mesozoic desert-period, the early Mesozoic age of 

 the basalts might be taken as established. But this hypothesis of 

 Dr. Passarge rests upon a highly speculative basis, and his evidence 

 that the superficial deposits laid down upon the plateau carry back 

 its history into Eocene times is by no means convincing. 



(4) The Flaggy Sandstone of Boonxka, etc. 



Along my route, the surface-sands and surface-quartzite presently 

 to be described were usually seen to rest directly upon the Batoka 

 Basalts of the plateau. At a few spots, notably along the northern 

 edge of the sand-bult between Matetsi and the head of the 

 Lukunguli basin, 4 the sands were indurated towards their base 

 into the condition of soft sandstone or ' sand-rock,' but the direct 

 relationship between this semi-indurated material and the incoherent 

 sand was clear. 



In going southward from Matheison's to Deka, however, I found 

 traces of a flaggy, dull-red or green, siliceous rock overlying the basalt, 

 differing in character from any material that I had hitherto seen 

 and apparently representing the relics of a stratified deposit. It 



1 'The Geology of Southern Rhodesia' Special Report No. 2, Rhodesia 

 Museum, Bulawayo, 1904, p. 17. 



2 'The Physical History of the "Victoria Falls' Geogr. Journ. vol. xxv 

 (1905) p. 46. 



3 ' Die Kalahari ' 1904, pp. 71, 82, 540-42 & Kartenband, Blatt ii. 



4 The Lukunguli River is known to the natives by this name in its lower 

 reaches only, toward its junction with the Matetsi ; its head-waters are known 

 to them as the Jambezi.. It is probably the same stream as the 'Myatambesi' 

 of Chapman's map, which has disappeared from the later maps. I intend 

 further to discuss some of these geographical matters in the notes which I am 

 preparing for publication in a geographical journal. 



