Wing Used for building purposes, and bearing a grdat 

 resemblance to oolite. On the east coast of the island 

 some of the sandstone lidges Avhich project into the pass 

 between the two islands have a similar composition to 

 those on the western side ; but a small low ridge form- 

 ing the margin of the shore forsoihe distance is totally 

 different being formed almost exclusively of the calci- 

 fied joints of an Alga, a species of Amphiroa -which is 

 abundant in the living state in the pass between Flat 

 and Gabriel islands, and is washed up in great quan- 

 tity at this particular point. 



From Flat Island we pass to Gabriel, separated from 

 it by a narrow pass with breakers at the north and south 

 extremities, caused by a connected chain of volcanic 

 boulders and blocks of coral to the north which are com- 

 pletely exposed by very low tides, and a passage afford- 

 ed, almost dry-shod from the one island to the othen 

 The southern reef is not so complete at it has several 

 openings through which boats can pass at high tide. 

 The space thus enclosed between the two islands and 

 the north and south reefs is very shallow not exceed- 

 ing at any part ten or twelve feet even at high tide. 

 The bottom is in some parts sandy, in others covered 

 with a forest of beautiful corals. 



Gabriel island resembles Flat island in its general 

 formation. The central portion which rises to a height 

 of 90 feet being formed by a large mass of volcanic 

 rock, variously broken into ridges and boulders, and in 

 many places covered by a thin layer of earth resulting 

 from the gradual decomposition of the volcanic rock. 

 The western side of the island opposite to Flat island 

 is bounded by a plain of sand nearly flat and rising 

 only a few feet above high-water mark, and a move- 

 able sand bank stretches out some distance into the 

 water towards Flat island. This sand-bank stretches 

 southward and to the east along the margin of the sea 

 nearly to the south-east point of the island and be- 

 tween it and a rocky point which almost forms an islet 

 at high tide. The layer of sand on the plain opposite 

 island, which is bounded on the inland side by an 

 elevated ridge of rock, is very superficial and covering 

 A layer of broken coral; and it gradually mix with vol- 



