332 PRIMEVAL AFRICAN MAMMALIA. 



appear there, which no longer exist in any of the 

 more recently formed territories. The fact of by far 

 the greater portion of Africa being situated within the 

 tropics, tends to render the survival of primeval races 

 there more probable than if such were not the case; 

 because the extinction of species seems more frequently 

 to be brought about by cold, than by any other agency. 

 Such, at all events, was the opinion of Professor 

 Agassiz, the well-known naturalist, who seems to have 

 been the first to recognize this probability * a doctrine 

 at present adopted by the majority of scientific men. 

 Mr. Wallace, for instance, thinks that we can hardly 

 fail to be right in attributing the wonderful changes 

 in animal and vegetable life that have occurred in 

 Europe and North America, to the intervention of two 

 or more glacial epochs, which he believes led to " the 

 extinction of a whole host of the higher animal forms" 

 and extensive variations in the vegetation of these 

 continents, f The fatal effects of cold upon the human 

 race, and its effects in raising the bills of mortality 

 at the present day, are well known, and we shall 

 have more to say upon this head elsewhere in these 

 pages. 



From whatever causes, however, it may proceed, there 

 seem to be good grounds for believing that the zone of 

 territory representing " The Great Bush Region" upon 

 the African continent is at this moment the home of 

 the oldest of all surviving types of animal life: and, 

 consequently, most probably of vegetable life also. 

 The celebrated German traveller and learned naturalist 



* See Island Life, by Alfred R. Wallace, 1880, Part i., Chapt. x, 



p. 222. 



f See Ibid., p. 119. 



