234 Prof. A. Agassiz on the 



matter to follow the various steps of the subsidence which 

 lias taken place here. Dana, in his last discussion of the 

 coral-reef question, states that it is impossible to find a better 

 series of islands than those of the Fiji to illustrate the gradual 

 changes brought about by subsidence, which transform a 

 volcanic island with a fringing reef to one with a barrier, and 

 next to one with a circular reef ring, and finally to one in 

 which the interior island has disappeared and has left only a 

 more or less circular reefing. For these reasons one of the 

 Fiji atolls promised to be an admirable location for boring and 

 settling the question of the thickness of the coral-reef of an 

 atoll. My surprise was great, therefore, to find within a mile 

 from Suva an elevated reef about 50 feet thick and 120 feet 

 above the level of the sea, the base of the reef being under- 

 laid by what is locally called soapstone, probably a kind of 

 stratified volcanic mud. The western extension of this reef 

 ran be traced at several points along the north shore of the 

 harbour of Suva, the island of Lanil)eka and Vua and Dra-ni- 

 mbotu, which are from 60 to 90 feet in elevation, being part 

 of an elevated reef extending to low-water mark. It was 

 this elevated reef or its extension westward which we traced 

 from the Singatoka Eiver to the Nandi waters. A short 

 distance inland from the mouth of the Singatoka there is a 

 bluff of about 250 feet in height, composed of a coral-reef 

 limestone which is the inner extension of the elevated reef- 

 patches and bluffs visible on the shore of Viti Levu. I am 

 informed by Dr. Corney that the islands of Viwa and Asa- 

 wailau to the northward of the Nandi waters are also remnants 

 of this elevated reef. 



But the traces of extensive elevation are not limited to the 

 larger island of Viti Levu. I found the islands on the rim of 

 the atoll of Ngele Levu to consist entirely of coral-rock 

 elevated to a height of over GO feet on the larger island. The 

 surface of the island where we crossed it was a mass of 

 hummocks of honeycombed, potted^ and eroded coral-masses 

 lesembling in every way the elevated reefs with which I had 

 become familiar in the Bahamas, Cuba, and Florida. The 

 northern sides of the island of Ngele Levu are on the very 

 outer edge of the rim of the lagoon, deep water running up 

 to the shore-line. We next found that at Vanua Mbalavu 

 the northern line of islands were parts of an elevated reef 

 forming vertical bluffs of coral-rock which had been raised by 

 the central volcanic mass of the main island to a heiglit of 

 over 500 feet at Ngillangillah, at Avea to 600 feet, at the 

 Savu Islands to 230 feet, and on the main island to a height 

 of nearly 600 feet. On the south of the main island the 



