chap, xi.] THE ETHIOPIAN REGION. 291 



tolerable rapidity, or if the elevatory force acted from the north 

 towards the south, there would be a new and unoccupied 

 territory to be taken possession of by immigrants from the 

 north, together with a few from the south and west. The more 

 highly -organized types from the great northern continent, how- 

 ever, would inevitably prevail ; and we should thus have 

 explained the curious uniformity in the fauna of so large an 

 area, together with the absence from it of those peculiar 

 Ethiopian types which so abundantly characterise the other 

 three sub-regions. 



We may now perhaps see the reason of the singular absence from 

 tropical Africa of deer and bears ; for these are both groups 

 which live in fertile or well-wooded countries, whereas the line 

 of immigration from Europe to Africa was probably always, as 

 now, to a great extent a dry and desert tract, suited to antelopes 

 and large felines, but almost impassable to deer and bears. We 

 find, too, that whereas remains of antelopes and giraffes abound 

 in the Miocene deposits of Greece, there were no deer (which 

 are perhaps a somewhat later development) ; neither were there 

 any bears, but numerous forms of Eelidse, Viverridge, Mustelidse, 

 and ancestral forms of Hycona, exactly suited to be the 

 progenitors of the most prevalent types of modern African 

 Zoology. 



There appears to have been one other change in the geo- 

 graphy of Africa and the Atlantic Ocean that requires notice. 

 The rather numerous cases of close similarity in the insect 

 forms of tropical Africa and America, seem to indicate some 

 better means of transmission, at a not very remote epoch, than 

 now exists. The vast depth of the Atlantic, and the absence of 

 any corresponding likeness in the vertebrate fauna, entirely 

 negative the idea of any union between the two countries ; 

 but a moderate extension of their shores towards each other is 

 not improbable, and this, with large islands in the place of the 

 Cape Verd group, St. Paul's Eocks, and Fernando Noronha, to 

 afford resting places in the Atlantic, w r ould probably suffice to 

 explain the amount of similarity that actually exists. 



Our knowledge of the geology and palaeontology of Africa 



