Land Connections of the African Continent 25 



scientists has ever troubled about the disposal of the vast mass 

 of water to be displaced by these hypothetical continents. 



It is of the greatest interest to the biologist to know exactly 

 or at least as near as possible, how land and water were divided 

 in the course of time. Grand conclusions are often based on 

 palaeogeographic maps constructed on extremely meagre facts, 

 and to this method we owe our great number of hypotheses on 

 tlie distribution of species. If the facts, which moved the student 

 to the construction of land bridges, are carefully examined, it 

 will be found, that they can also be explained in some other 

 way and that, therefore, those land connections are not necessary. 

 This is especially the case with the African continent except 

 for its northern and north-eastern limits, where connections with 

 Europe and Asia must be accepted. There is no valid evidence 

 to prove, that Africa was ever connected with any other conti- 

 nent and I therefore put the following thesis: Africa has always 

 been ocean bound except in the north and north-east, where it 

 was occasionally connected to Europe and Asia. 



We will first examine the geological evidence, amongst which 

 the slratigraphical is the most important. The latter evidence 

 may be divided into two sections, that which depends chiefly 

 on the determination of facies and that which is afforded by 

 the great marine transgressions. In identifying the facies we 

 determine the presence of land or water at a certain spot or 

 the relative distance of a former seashore at a given time. The 

 same may be done for other localities, and the surest conclusions 

 will be gathered if these localities are many, close together and 

 when the studied phenomena lie within the narrowest possible 

 time limits. 



Rocks of Santonian (Upper Cretaceous) age have been found 

 on different parts of our east coast. In Pondoland the coastal 

 deposits of this age form the coast of to-day, the deposits even 

 entering present river channels. There can therefore be no doubt, 

 that at the time when these beds were deposited the Pondoland 

 coast was right where it is now. Further north, in Natal and 

 Zululand, rocks of the same age occur at some distance from 

 the present shore. In Kenya rocks of probably the s 



luJ L I B R A R V 



