BY W. G. WOOLNOUGH. 491 



of faults, as in the formation of the Mozambique Channel, or may 

 have formed a wide S3^nclinal fold without dislocation. 



In the case of Madagascar, definite faults have been traced and 

 measured. That no such faults have been observed in Fiji does 

 not definitely prove that they do not exist. It is quite possible 

 that if great faults have been formed, denudation and cutting 

 back of the coast line may have completely hidden their traces. 

 Additional detailed work may reveal their existence. 



As stated above in the Summary of Results, there is rea^n to 

 believe that Viti Levu consists of a core of very ancient, perhaps 

 Archaean rook, surrounded and partially covered by marine 

 deposits of Tertiary and Recent Age, and Cainozoic lavas. So far, 

 no traces of Palaeozoic or Mesozoic formations have been observed. 



This structure may be explained in various ways. The area 

 may have been one of prolonged and continuous subsidence since 

 very early geological time. It is conceivable that all the geological 

 formations from Cambrian to Tertiary may have been deposited 

 in orderly sequence upon a basis of Archaean rocks w^iich were 

 slowly sinking. 



If such an event were to happen, denudation would be con- 

 stantly reducing the bulk of the ancient continent, whose borders 

 would also shrink as it became submerged. For these reasons the 

 amount of material entering into the composition of each forma- 

 tion will be constantly on the decrease, and the tendency would 

 be not to fill up the sea with sedimentary deposits so as to keep 

 it approximately the same depth throughout, but to have an 

 ocean becoming constantly deeper as time went on. Abundant 

 evidence has been brought forward to prove that an elevation 

 amounting to at least 1290 feet in Yiti Levu, viz., at Drau, and 

 as much as 1050 feet at Yatu Yara has taken place since Tertiary 

 time. This elevation would not be suflicient to bring to light the 

 older formations. 



It is very unlikely that such a movement would be continuous. 

 It would no doubt be oscillatory, but with the general tendency 

 towards depression of the land, and the nett result a considerable 

 subsidence. 



