FAKARAVA. 83 



is one of the richest collecting grounds we have met, though many reef 

 flats in other islands of the group similarly situated are comparatively 

 poor in animal life. The finger-like scalloping of the outer edge of the 

 reef platform is also well indicated at Fakarava. 



The bottom samples of the lagoon, wherever collected, indicate the 

 presence of coral sand made up of Nullipores, of corallines, and of frag- 

 ments of corals reduced to minute pieces by boring sponges and Algas, of 

 broken parts of echinoderms and moUusks as well as Foraminifera. 



On the lagoon side of Fakarava near the village of Rotoava, in from 

 two to three fathoms of water, are numerous fine patches of corals com- 

 posed of Astraeans, Porites, Goniastrfeans, and Madrepores. In somewhat 

 deeper water these patches become larger and run out into 8 to 10 

 fathoms. The same condition exists on the slopes of the shoals, sand bars, 

 and islets, the corals appearing to be most flourishing in from 5 to 9 or 10 

 fathoms. As we passed out of the Ngarue Pass, we could see in the pass 

 and on the outer slope, down to 17 or 18 fathoms, a fine growth of large 

 masses of corals, which rapidly became separated by wider and wider 

 patches of fine white sand, till the coral patches disappeared completely in 

 from 20 to 22 fixthoms. 



Skirting along the north shore of Fakai'ava, the land rim islands are 

 flanked by long stretches of sand beaches. Long reaches of coral rag 

 shingle extend along the eastern face of the island. These sometimes form 

 high beaches, and between them low channels have been cut, such as we 

 found back of the village of Rotoava. 



The west side has not been built up as much as the other, and the 

 material washed over the western Hat has formed the wide reef flat of 

 the weather side. The sand bars and sand islets are always on the lagoon 

 side of the flat where islands are ultimately developed ; lines of beach 

 rock or of coral boulders or fragments of the old ledge run across the flat, 

 generally at right angles to the outer edge, with larger boulders or negro- 

 heads of old ledge or beach rock or recent conglomerate on the outer edge 

 of the sea face of the reef flat, across which here and there wide gaps, some- 

 what deeper than the rest of the reef flat, allow the water freer access to the 

 lagoon than elsewhere. 



