62 APPENDIX. [sect. 



A geological map of Mr Bain, and some former discoveries 

 of Dr Livingstone and Mr Oswell, were probably the germ 

 of this idea. Dr Livingstone at this time was in central 

 Africa, far away from all communication with Europeans. 

 He by observation arrived independently at the same con- 

 clusion, and on reaching Linyanti, on his return from Loanda, 

 received Sir R. I. Murchison's demonstration in the box 

 sent him by Mr Moffat. The notice of the following facts 

 first led him to arrive at the same conclusion. In passing 

 northwards to Angola, the presence of large Cape heaths, rho- 

 dodendrons, Alpine roses, and especially the sudden descent 

 into the valley of the Quango, near Cassange, led him to be- 

 lieve that they had been travelling on an elevated plateau. 

 This conviction was confirmed by observations made with a 

 thermometer and boiling water, whereby he took altitudes at 

 various points 1 . Moreover, he found that several rivers which 



-which form her outer fringe, unquestionably circled round an interior 

 marshy or lacustrine country, in which the Dicynodon flourished, at a 

 time when not a single animal was similar to any living thing which 

 now inhabits the surface of our globe. The present central and meridian 

 zone of w r aters, whether lakes or marshes, extending from Lake Chad 

 to Lake Ngami, with hippopotami on their banks, are therefore but the 

 great modern residual geographical phenomena of those of a mesozoic 

 age. The differences, however, between the geological past of Africa 

 and her present state, are enormous. Since that primeval time, the 

 lands have been much elevated above the sea-level — eruptive rocks 

 piercing in parts through them ; deep rents and defiles have been 

 suddenly formed in the subtending ridges through which some rivers 

 escape outwards. 



"Travellers will eventually ascertain whether the basin-shaped 

 structure, which is here announced as having been the great feature of 

 the most ancient, as it is of the actual geography of South Africa (i. e. 

 from primeval times to the present day), does, or does not, extend into 

 Northern Africa. Looking at that much broader portion of the conti- 

 nent, we have some reason to surmise that the higher mountains also 

 form, in a general sense, its flanks only." — p. cxxiii. President's Address, 

 Royal Geographical Society, 1852. 



1 Letter, dated Linvanti. 



