﻿(«) Eviden e from Faulting. 



In the district north of Mo- 

 kambo Bay, between the Monapo 

 and Mitikiti Rivers, sheets of 

 amygdaloid are seen to lie succes- 

 sively on a surface of Cretaceous 

 sandstones and limestones, and 

 on far older crystalline rocks. At 

 Mitikiti's Kraal, only occasional 

 pebbles of agate and jasper re- 

 main to prove the former extension 

 of the flows. The junctions be- 

 tween sandstone and limestone 

 and between limestone and gneiss 

 are faulted, and it is evident that 

 denudation kept pace with the 

 movement and reduced the various 

 formations to a nearly plane sur- 

 face before volcanic activity com- 

 menced. Unfortunately, it is not 

 easy to determine the period of 

 faulting. The Oligocene deposits 

 of Lumbo, on the southern shore 

 of Mosuril Bay, are probably 

 faulted down against the Creta- 

 ceous sandstone, but the move- 

 ment there may not have been 

 simultaneous with that within the 

 Cretaceous sediments, nor with 

 that between the latter and the 

 Pre- Cambrian complex. If it be 

 conceded that all the faulting is 

 of approximately the same period, 

 the time of extrusion could not be 

 earlier than the Oligocene ; but, 

 as this assumption is itself not 

 securely founded, the evidence 

 points to a period no more definite 

 than post- Cretaceous. 



(b) Evidence from the Age 

 of Intruded .Sediments. 



The phonolite of the Sanhuti 

 River and the amygdaloids 

 throughout the area are neces- 

 sarily post- Cretaceous, since they 

 He partly on a base-levelled Cre- 

 taceous platform. At Mochelia, 

 however, Mr. Wayland found a 

 number of dykes intrusive 

 through sandstone and conglo- 

 merate, which he interpreted a 



