13S E. C. Andrews — Coral Reefs in the Fiji Islands. 



tas at their heads. Moreover, these salt water arms occupy the 

 lower portions of valleys which belong to the type now uni- 

 versally admitted to be formed by ordinary stream action. 

 The Viti Levn salt water arms, therefore, with their contained 

 deltas suggest the submergence of the Yiti Levu coastal low- 

 lands in recent time, with the consequent drowning of the 

 lower portions of the river courses. 



The island is girt with a Great Barrier Reef, several hun- 

 dreds of miles in length, broken here and there by passages. 

 The present Great Barrier Reef, which rises to the level of the 

 sea, has thus, in all probability, been built up by coral-reef 

 organisms upon the submerged lowlands of Yiti Levu. 



Vanua Levu. — The topography of this great island (2,700 

 square miles) is very similar to that of Yiti Levu, and the main 

 points in the history of its Barrier Reef may be explained in a 

 similar manner. 



Yanua Mbalavu. — This is one island, among several, lying 

 within a large lagoon encircled by a barrier reef. The name 

 signifies 'The Long Land.' The island itself has the shape of 

 a distorted S, and consists of volcanic rock in the central por- 

 tion dissected by ordinary stream action, and covered with 

 deep deposits of tala-singa, or red earth, and terminated both 

 north and south by masses of dense 'coral-reef limestone, 

 reaching a height of 500 feet. The volcanic rock of the central 

 portion of Yanua Mbalavu also rises to similar heights. The 

 raised ' reef-limestones ' occurring north and south of the 

 island overlie large masses of hard, granular, well-bedded, and 

 evenly-dipping limestone. Well-bedded layers of fine volcanic 

 ash (Fiji soapstone), with even dip, also occur at Yanua Mba- 

 lavu, but such beds were observed only as denuded islets near 

 the island itself, and their relations to the ' coral-reef ' lime- 

 stone were not ascertained. In Mango, however, an island 

 distant only a few miles from Yanua Mbalavu, soapstone 

 beds of similar nature were observed dipping at an angle of 15 

 degrees, and capped by horizontal masses of reef limestone. 

 The ' reef ' limestones in the north of Yanua Mbalavu form 

 islets separated by deep-water lanes, which pass, in one portion 

 of Yanua Mbalavu at least, into a deep harbor running up 

 among bedded limestones on the one side and. volcanic rocks 

 on the other. This harbor also belongs to the type universally 

 admitted as drowned stream valleys, the valley having been 

 formed by stream erosion in the first place while its profiles 

 may be seen to have been partly submerged in recent geologi- 

 cal time. 



The association of these features suggests a basement of 

 limestone and volcanic ash, originally deposited as beds of 

 gentle, or negligible, dip. These appear to have been tilted 



