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 Jirma 
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 Jirma , which 
in equatorial Africa were said not to exist, on a scale only rivalled elsewhere in the 
region of the southern Andes. 
