GEOLOGY. 273 



suddenly formed in the subtending ridges, through -which some rivers 

 escape outwards, whilst others flowing inwards are lost in the interior 

 sands and lakes ; and with those great ancient changes entirely new 

 races have been created. 



Travellers, continues Mr. Murchison, 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 Southern 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 Continent, we have 

 some reason to surmise, that the higher mountains also form, in a 

 general sense, its flanks only. Thus, w T herever the sources of the 

 Nile may be ultimately fixed and defined, we are now pretty well 

 assured that they lie in lofty mountains at no jrreat distance from its 



v * i t 



east coast. In the absence of adequate data, w r e are not yet entitled 

 to speculate too confidently on the true sources of the White Nile ; 

 but judging from the observations of the missionaries, and the position 

 of the snow-capped mountains called Kilnianjaro and Kenin, (only 

 distant from the eastern sea about 300 miles,) it may be said that 

 there is no exploration in Africa, to which greater value w r ould be 

 attached than an ascent of them from the east coast, possibly from 

 near Mombas. The adventurous travellers, who shall first lay down 

 the true position of these equatorial snowy mountains, and shall 

 satisfy us that they not only throw off the waters of the White Nile 

 to the north, but some to the east, and will further answer the query, 

 whether they may not also shed off other streams to a great lacus- 

 trine and sandy interior of this continent, will justly be considered 

 among the greatest benefactors of this age to geographical science. 



The great east and west range of the Atlas, which in a similar 

 general sense forms the northern frontier of Africa, is, indeed, 

 already known to be composed of primeval strata, and eruptive rocks, 

 like those which encircle the Cape Colony on the south, and is 

 equally fissured by transverse rents. As to the hills which fringe the 

 west coast, and through the apertures of which the Niger and the 

 Gambia escape, we have yet to learn if they are representatives of 

 similar ancient rocks, and thus complete the analogy of Northern 

 with Southern Africa. But I venture to throw out the general sug- 

 gestion of an original basin-like arrangement of all Africa, through 

 the existence of a grand encircling girdle of the older rocks, which, 

 though exhibited at certain distances from her present shores, is still 

 external as regards her vast interior. 



With no region of the old world have we been, till very lately, so 

 ill-acquainted as Africa. But now the light is dawning quickly 

 upon us from all sides ; and in the generation which follows, I have 

 no doubt that many of the links in the chain of inductive reasoning, 

 as to the history of the successively lost races of that part of the 

 globe, will be made known, from the earliest recognizable zones of 

 animal life, through the secondary and tertiary periods of geologists. 

 Passing thence to the creation of mankind, and to the subsequent 



