4 THE TANGANYIKA PROBLEM. 



tingly run amuck amongst some cherished geological ideas. 

 It appeared, that in 1852 Sir Roderick Murchison, collecting- 

 such material and geological facts as were then available, had 

 arrived at the conclusion that the interior of Africa had 

 never been beneath the sea, and supposed, as he then said, 

 this view to be " confirmed by the absence south of the 

 equator of all those volcanic activities which we are 

 accustomed to associate with oscillations of terra fir "ma."* 

 In the light of our newer zoological evidence, the first part 

 of this statement would appear consequently to be wrong, on 

 account of the anatomical characters of the Tanganyika 

 fauna, which relegate a portion of this fauna to a 

 marine stock, and show that this part of Africa has 

 been at some time connected with the sea, in order that 

 such marine animals could get into it. While the second 

 part of the statement, that is, the assumed evidence 

 respecting the permanence of the African land-mass 

 drawn from the then apparent absence of volcanic 

 activities south of the equator, is now, also, entirely dis- 

 proved, intense volcanic activity having been found to 

 have occurred, and to be occurring, throughout all these 

 regions, f 



In a number of subsequent papers dealing with different 

 portions of the same problem, I therefore reiterated all that I 

 had previously said with respect to Tanganyika having been 

 connected with the sea. For the existence of the medusae 



* Journal of 'the Royal Geographical Society, vol. xxiv. 1864, pp. clxxv. — clxxviii. 



t This is shown (1) by the discovery of the active volcanoes north of Kivu, (2) by the 

 discovery of the recent cones and active geysers all round the north and east of the Albert 

 Edward Nyanza, (3) by the discovery of the lava fields on the west of Tanganyika, 



(4) by the discovery of the existence of groups of extinct volcanic cones north of Nyassa, 



(5) by the presence of lava flows as far south as Shirwa, and finally (6) by the demon- 

 stration of the existence and continuance of those very oscillations of terra fir ma, which 

 in equatorial Africa were said not to exist, on a scale only rivalled elsewhere in the 

 region of the southern Andes. 



