70 APPENDIX. [sect. 



delight angels, and make mortals for the moment forget the sin, 

 sorrow, and shame of the first Adam's fall, everywhere so visible 

 in this lower world a magnificent wreck of former grandeur ! 



Geology and Mineralogy. 



" The earth was without form, and void ; and darkness was upon the 

 face of the deep." — Gen. i. 2. 



The references to these sciences in the Book of Travels, are 

 numerous and valuable. At page 569, is " an ideal section 

 across south central Africa, intended to shew the elevated 

 valley form of the continent." An examination of this section 

 will much help to explain what is said about the ridges and 

 river-system in the foregoing paragraphs. 



It appears that both coasts consist of calcareous tufa; and 

 the western ridge of mica schist and sandstone. The great 

 central plateau is formed of tufa, trap, and radiated zeolite. 

 White basaltic rocks, mica schist, granite and trap make up 

 the eastern ridge ; coal in sandstone, and igneous rocks inter- 

 vening between them and the calcareous tufa bordering on the 

 sea. 



The general direction of the ranges of hills on the eastern 

 and western ridges appear to be parallel to the major axis of 

 the continent: the dip of the strata down towards the centre 

 of the country shewing that Africa in its formation was pressed 

 up more energetically at the sides than at the centre 1 . 



Our traveller suggests that the fissures which have drained 

 the great central plateau are possibly geologically recent, be- 

 cause the one at the Victoria Falls has only about 3 feet worn 

 off the edge subjected to the wear of the water; and that 

 they may be progressive in case the gradual desiccation of the 

 Bechuana countrv shews the slow elevation of the ridoes 2 . 



He found, near the Chiponga, a forest of silicified trees , 

 some 22 inches in diameter; also near the Zambesi, towards 



1 Letter dated Linyanti. 2 Letter dated Hill Chanyune. 



