GEOLOGICAL OBSERVATIONS IN FIJI. 



21 



of them are so low and so deeply lateritized tliat they have been 

 leveled by the sugar planters. 



Along the east sitle of the ri\er near its mouth, mangrove swamps 

 once covered an area of dead coral reef for a mile inland. The dead 

 reef does not rise above the present low-tide level. A considerable 

 period of coastal stability, permitting the river-muds to be built 

 forward oAer the dead reef for such a distance, is here indicated. 



At a point a few miles west of the mouth of the river there are traces 

 of an uplifted sea beach (Holmes, Government Surveyor). Other 

 e^'idences of recent uplift are seen in the bench levels along the 

 banks of the Navua, 8 or 10 miles from its mouth. The torrential 





Figure 8. View of the Southern Coast of Viti Levu, near Tangani. 



streams, entering the rWer, flow across small delta flats before they 

 reach the main stream. Eight miles up the river the uplift is esti- 

 mated to be from 6 to 8 feet. It would appear that the Navua dis- 

 trict either stood still or was downwarped during the period in which 

 the coastal plain was uplifted to the west. More recently a slight 

 uplift of the river's delta has taken place. 



The Navua river, like the Singatoka, drains an area in part com- 

 posed of granites and diorites; hence a considerable amount of coarser 

 material is mixed with the fine clay of the river deposits. In exten- 

 sive gravel flats, 10 or 12 miles from the river's mouth, boulders of 



