VII.] PAST HISTORY. 255 



of -the distinction between the Ethiopian and Oriental regions, 

 which some have proposed to unite. It is, however, somewhat 

 remarkable that secretary-birds (Serpentarius) are unknown in 

 Madagascar, seeing that they are represented in the upper Oligo- 

 cene of France, and may therefore be presumed to have entered 

 Ethiopia with the ancestral lemuroids and civets. Finally, the 

 ostriches (Struthio), which are now mainly confined to Africa and 

 Syria, are evidently recent immigrants into the region, the genus 

 being represented in a fossil state in the Indian Pliocene. 



With the exception of the occurrence of remains of certain 

 existing species, such as Rhinoceros simus, Phaco- 

 charus, etc., in the superficial deposits of southern 

 Africa, nothing is known of the mammalian Tertiary 

 palaeontology of the Ethiopian region. Fortunately, however, the 

 clue given by the existing fauna of Madagascar and the Tertiary 

 faunas of Europe and southern Asia enables a considerable portion 

 of the past history of the population of the region to be given with 

 a fair degree of completeness. And here, with one important 

 exception, Dr Wallace's explanation, as given in the Geographical 

 Distribution of Animals 1 > may be accepted almost in its 

 entirety; the one exception being, as mentioned in an earlier 

 chapter, that the Sahara was never a sea during Tertiary times ; 

 although it appears always to have formed a barrier between 

 northern Africa and Ethiopia. As already mentioned, the an- 

 cestral types of the existing mammalian fauna of Madagascar ob- 

 tained an entrance into Ethiopia some time during the Oligocene 

 period, and soon after ranged over the whole of what are now the 

 Ethiopian and Malagasy regions, which were then united and 

 possessed a common fauna. During the Pliocene age, when 

 Madagascar had become isolated, came the great irruption into 

 Ethiopia, of the higher and larger mammals, such as apes, monkeys, 

 ungulates, etc., which were then flourishing all along southern 

 Europe and Asia. Finding the country unoccupied and eminently 

 suited to their existence, these rapidly attained a development now 

 unequalled in any other part of the world ; many new genera being 

 apparently evolved within the Ethiopian area, although a large 



1 Vol. i. p. 285 292. 



