472 A CONTRIBUTION TO THE GEOLOGY OF VITI LEVU, FIJI, 



There is abundant evidence, particularly in the Revva Valley, 

 that the earth-movements have been chiefly positive, and that 

 they are probably still in operation. There are remains of older 

 delta-deposits about the head of the present delta, and about 

 *200 feet above its level. This intermittent, but probably not 

 oscillatory, uplift may account for the entire absence of lakes in 

 such a youthful topography. The only possible evidence of lakes 

 is in connection with the Wainivalau Valley. This stream was 

 probably temporarily dammed by the elevation of the Medrausucu 

 Range. 



Most, or all, of the streams flowing across the trend of this 

 range are excellent examples of " antecedent rivers." In the 

 case of the Waieliu (Former River) there seems to be a suggestion 

 of river-capture having taken place on a large scale within 

 historic time. 



The rivers of the north-west have not been critically examined, 

 but their distribution shows that there is a very fine field there 

 for physiographic research. 



Conclusion. 



The accumulation of evidence, both of a geological and of a 

 geographical nature, while it [)oints to certain mistakes in detail 

 in my former work, on the whole strongly bears out the conclu- 

 sions arrived at in the paper presented to this Society about 

 four years ago. 



The great extension of granitic and slaty rocks, their base- 

 levelling to form a peneplain, their relativel}^ great age, as proved 

 by the occurrence above them of basal conglomerates of Tertiary- 

 age, and the occurrence of very heavy systematic faulting, all 

 lead towards the conclusion that Viti Levu, and therefore pro- 

 bably the whole of Fiji, has been a land-area for enormous 

 periods of time, even reckoned geologically. It has had sufficient 

 magnitude and durability to permit of earth-movements competent 

 to produce schists : it has existed so long as a land-surface that 

 large rivers have had time to reduce it to base-level. These facts 

 constitute in my mind the essentials of a continental area. Its 

 relationships to the surrounding continental masses have been 



